Rail Engineer - Issue 142 - August 2016

Engineer

by rail engineers for rail engineers

AUGUST 2016 - ISSUE 142

Harringworth half-term report

GLASGOW QUEEN STREET

NEW LINCOLN FOOTBRIDGE

IMECHE RAILWAY CHALLENGE

The high-level station is closed while track is replaced in the tunnel and station throat.

Demolishing half a building to make way for a new footbridge that improves safety on a busy level crossing.

The fifth annual competition requiring graduates and apprentices to design and build their own locomotives.

www.railengineer.uk

THA FO NK Y R CAM SUP OU PAI PORT ARC GN O I IN NG O !

SCH U OO R LS

Rail Engineer • August 2016

Contents

Lateral thinking in Lincoln

A new footbridge that improves safety on a busy level crossing.

20 High-output track renewal, German-style

58 London Bridge Station What is planned for the western end over the coming August bank holiday.

66 A testing weekend at Stapleford

70

3

Planning for a world’s first ElevArch masonry arch jacking trial.

16

Bermondsey dive under Removing another critical pinch point.

24

Bedford’s bypass bridge A new bypass over the Midland Main line.

28

Opposing forces Graeme Bickerdike recounts the tale of Torksey viaduct.

32

New footbridge old design A brand new 'old' footbridge for Sheringham.

37

Port Talbot showcase A new station footbridge and improved facilities

38

141 days at Queen Street Heavy engineering going on at Queen Street station.

40

Tamping essential for good track alignment Balfour Beatty’s Geoff Brown fills in the detail.

46

Landfill journeys Environmentally friendly recycled-plastic composite sleepers.

50

Milling damaged track A self-contained road-rail milling machine.

54

High ideas Rising to the challenge of overhead line equipment.

62

An emerging force in rail Further works taking place at Harbury.

76

Engineering directors gather Senior engineers agree joint actions in an open forum.

80

Improved transmissions for 158s Developments to improve fuel economy.

82

Advanced energy management Innovative design reduces energy consumption.

84

UK’s most advanced carriage wash A single pass unidirectional unit.

88

See more at www.railengineer.uk

We’re looking to highlight the latest projects and innovations in

Concrete/Earthworks/Drainage

Innovation

in the October issue of Rail Engineer.

Got a fantastic innovation? Working on a great project? Call Nigel on 01530 816 445 NOW!

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Rail Engineer • August 2016

And the new Secretary of State for Transport is...

Editor Grahame Taylor grahame.taylor@railengineer.uk

Production Editor Nigel Wordsworth

5

GRAHAME TAYLOR

nigel.wordsworth@railengineer.uk

Production and design Adam O’Connor adam@rail-media.com Matthew Stokes matt@rail-media.com

Engineering writers bob.wright@railengineer.uk chris.parker@railengineer.uk clive.kessell@railengineer.uk collin.carr@railengineer.uk david.bickell@railengineer.uk david.shirres@railengineer.uk graeme.bickerdike@railengineer.uk malcolm.dobell@railengineer.uk melanie.oxley@railengineer.uk mark.phillips@railengineer.uk paul.darlington@railengineer.uk peter.stanton@railengineer.uk stuart.marsh@railengineer.uk

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But first, just to maintain the suspense, we’ll deal with some engineering. Our two features this month, bridges & tunnels and track, are so intertwined, so interdependent, that it’s not easy to separate them out.

Looking at structures, we have, at one end of the scale, the huge Harringworth viaduct. With twenty million bricks placed on top of each other in the late nineteenth century, it’s now time to work out how to keep them all in the correct order, especially as they carry some very heavy freight trains. Chris Parker went off to see this giant Jenga kit.

At the other end of the scale we cover a footbridge renewal which posed some very tricky problems. Nigel Wordsworth tells the story of a new footbridge in Lincoln.

It’s large because of the stairs and the lifts and everything else needed these days. It was needed because Lincoln has a level crossing that is much easier to cross - although dangerous when people are in a hurry.

Perhaps there are plenty of spare old footbridges around - the classic lattice variety. The problem is, of course, that many are as rotten as pears and don’t take kindly to being handled, however gently. So Bob Wright dusted off his drawing skills and his tee square and produced a brand new old footbridge for Sheringham.

For an example of the challenges of a road-over-rail bridge, we travel to the outskirts of Bedford and hear from Tim Burgess how the new bypass was carried over the Midland main line.

Look out for a new arch jacking process that is going to be trialled in the autumn. The idea is to tackle a whole brick-built bridge arch, raise it up in one piece and avoid all the hassle of demolition. Should be interesting!

Interesting was not necessarily the word used back in 1849 by Captain Lintorn Simmons of the Royal Engineers who came to inspect a new form of bridge beam construction. Hollow section main girders got a load of flack in the early days as Graeme Bickerdike recounts the tale of Torksey viaduct.

Combining a mixture of tunnels and track, we visit Glasgow with David Shirres to look at the heavy engineering going on as Queen Street station and its approaches are equipped for longer and more frequent trains.

Anyone familiar with the approaches to London Bridge will appreciate the complexity of adding any extra infrastructure. When that extra piece of infrastructure is the new dive-under at Bermondsey, then complexity takes on an added meaning. Collin Carr went off to see how everything is being shoehorned into position.

The dive-under is the eastern part of the London Bridge project. Clive looks at what is planned for the Western end over the coming August bank holiday. In amongst a whole raft of activities, look out for the introduction of a railway contra-flow system designed to squeeze as much capacity out of the interim arrangements.

We kick off our track features with a piece by Geoff Brown from Balfour Beatty giving us a guide to tamping - what it is and why it’s needed. Then Achim Uhlenhut of Plasser & Theurer expands on the tamping theme with an account of track renewals between Hamburg to Cuxhaven in Germany this year.

There was an interesting track product on display at Rail Live - it was a plastic sleeper. Just the one, but a representative of many more that are made from scrap plastic. It’s landfill Jim, but not as we know it.

Also at Rail Live were a couple of very impressive roadrail machines. One, designed and operated by Keltbray, is used to run out overhead line equipment instead of relying on trains. The other was a substantial beast - a self-contained road-rail articulated lorry that’s actually a milling machine!

Malcolm Dobell explores the world of final drives and gearboxes, looking especially at developments designed to improve fuel economy. It’s a world of modified automotive-derived equipment - although lorries rarely go as fast in reverse as they do in forward gear.

Old Oak Common depot is perhaps an unlikely venue for an advanced energy management system but, as Tony Amis and Mike Beagle recount, just about every trick in the energy book has been used to good effect.

It’s that time of year again - the time when aspiring young engineers build their own designs of miniature locomotives to compete in the IMechE Railway Challenge at the Stapleford Miniature Railway. David Shirres was there to witness the ups and downs, as well as the ons and offs.

Nigel’s round of business engagements has included a session of the Engineering Directors’ Forum, a gathering of senior directors from the companies that design, build and maintain the railway. Time ran out for a discussion on whole-life costing - that’ll need to wait for the next one in November And what happened to the railway at Harbury? The tunnel, the slip, the damaged wing walls, the blocked railway. Collin looks at what has been involved, and forward to works this month that should just about fix the whole problem.

And hot off the press is Nigel’s exclusive interview with Chris Grayling (pictured above), the government’s new Secretary of State for Transport - someone who takes a real interest in the industry.

6

NEWS

Rail Engineer • August 2016

New Government supports rail Chris Grayling the Secretary of State speaks exclusively to Rail Engineer

Secretary of State Chris Grayling gave his first public speech since taking office to the Rail Delivery Group recently. Five minutes later, he was speaking exclusively to Rail Engineer.

Although he had only been in office for five days at that stage, and was hardly likely to make major policy announcements, what he said was interesting.

First of all, he was obviously pleased to have been appointed Transport Secretary. “This is the job that I’ve always been most interested in doing in government, it’s the area that has been my prime focus for political interest since I arrived in 2001 and joined the Transport Select Committee, since I shadowed this brief in opposition,” he told the RDG. “I’m really excited by many of the things that have happened over the past few years, things that were glints in the designer’s eye that have now become a reality,” he continued.

“So it’s a really exciting time for the industry, but there are big

challenges ahead, there are still very big capacity issues. And I guess my one message to all of you would be - please think in everything you do, every decision you take, every plan you put together, that the thing I want more than anything else for the whole industry is to make life better for the passenger. Because that fundamentally should drive absolutely every decision we take.”

Having set out his basic philosophy, Rail Engineer asked about continuity of work for the railway engineering industry.

“A change in personnel doesn’t mean a change in strategy,” the new Secretary of State told Rail Engineer, “and the fact is that the government, since 2010 and now in the 2015 parliament, has been very committed to the rail industry, has had long-term plans. We are probably doing more to invest in the railways in all its different guises - from the engineering on the track, to rolling stock, to the control system - than any government has done for decades.

“That is not going to change. If you look at the trends on capacity, if we stopped we’d be causing a huge political problem for ourselves. So there is absolutely no intention of stopping. As far as the industry is concerned, it is business as usual but with a new Secretary of State who is very keen to support the industry.”

Would there be any more ‘pauses’, projects suspended while plans were assessed, that could cause problems for contractors already gearing up to work on those projects?

“I have no current plans to stop any project that is currently happening,” he replied. “I’ve no plans to reign back on the investment programme. I’m not going to give blanket guarantees in perpetuity for all projects everywhere on the network, but people should not expect the government to be putting the brakes on their investment.”

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8

NEWS

Rail Engineer • August 2016

Crossrail platforms complete Platforms are now complete at all Crossrail stations in central London, which leaves just Whitechapel to complete.

Most recently, the two 240-metre long platforms at Liverpool Street have been completed. They were pre-fabricated in more than 500 pieces by Laing O’Rourke at Steetley near Sheffield, 130 miles away, and then brought to London by road to be assembled on site after first being lowered down the main access shaft.

“Assembling the two platforms

piece-by-piece over the last few months has been a bit like putting together a giant jigsaw puzzle,” commented Rohan Perin, Crossrail project manager at Liverpool Street.

“Prefabricating and then assembling the sections together on site has meant that we can get on with the job quickly and safely.”

The new platforms form part of the Elizabeth line, as Crossrail will

be renamed when it opens in 2018.

They took four months to install and are around twice as long as the platforms to be found on London Underground stations. Crossrail is being built for full-sized mainline trains, each 200 metres long.

The Liverpool Street platforms lent themselves to a prefabricated approach due to their proximity to the large access shaft, down

which heavy components could be lowered. All other platforms, with no similar shaft nearby, were cast in situ from concrete pumped down from street level.

So far, nearly four kilometres of platforms have been built at stations from Paddington to Woolwich. Work continues at just one, Whitechapel, which will be complete by the end of the year.

New watering hole at Diss A new micro-pub opens at Diss station.

Rail engineers in Norfolk may be pleased to hear that, once their work is done, they can relax at a new micro-pub that has been opened in a disused area of Diss station.

Named The Jolly Porter, in memory of a public house that operated near the station during the 1960s, the tiny pub offers a range of locally-brewed ales from the Hoxne brewery, Old Chimney brewery and Shorts Farm brewery, together with a range of local ciders, prosecco, red and white wine and soft drinks.

The new micro-pub is the brainchild of Dan Steggles, an expoliceman and owner of the Hoxne Brewery, who saw the opportunity to create a small bar and beer garden as a watering hole for commuters but also to serve the new housing estates around the station with quality local products

and a convivial atmosphere.

“I’d heard about the concept of micro pubs taking over empty buildings and providing a place to enjoy a drink and a chat with no games machines, juke boxes or TVs,” said Dan. “When I saw that part of the station building at Diss was up for let I knew the model would work and Abellio Greater Anglia was very open to the idea.”

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10

NEWS

Rail Engineer • August 2016

Nottingham's icing on the cake Although Nottingham station reopened after a major rebuild in October 2014, it wasn't finished.

The Grade II* listed station was closed for 37 days in 2013 for new signalling and a revised track layout, and then reopened properly once all the work was completed a new platform, a bridge over the station to take the extended tram network, and a new concourse formed by glazing-in the portecochère and evicting the taxis.

But there was still work to do.

The distinctive red façade that gives the station its iconic look included decorative terracotta pieces around the top, and they were damaged.

So Network Rail brought in some specialist artisan manufacturers and selected old pieces were carefully removed by hand. Then new pieces were cast using a process that has not changed since the nineteenth century.

In total, 42 new pieces were

manufactured and installed.

Steel struts, which had been installed to support the remaining terracotta mouldings while the new replacements were being made, could then be removed.

After viewing the result, Network Rail project manager Jacquie Brown said: “The craftsmen have done a wonderful job. Each individual piece of terracotta had to be an exact fit because they shrink when they are fired - it’s like replacing a jigsaw puzzle and the result is amazing. It really is the icing on the cake in the restoration of this beautiful station.”

Network Rail worked with Historic England on the restoration while the whole redevelopment programme was carried out in conjunction with Nottingham City Council, East Midlands Trains and the Rail Heritage Trust.

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Rail Engineer • August 2016

BRIDGES AND TUNNELS

CHRIS PARKER

Harringworth half-term report

H

arringworth Viaduct is a major structure on the line between Manton Junction and Corby, set in glorious Northamptonshire countryside. It is a brick arch structure, 1,182 metres long with 82 spans, three of which cross roads and one of which crosses the River Welland, and was built between 1876 and 1878 using bricks made in three brick kilns on the site.

that they have been in the past. Harringworth Viaduct is Grade 2 listed, and a great deal of effort is being given to maintaining its appearance unchanged.

Rail Engineer has reported upon previous work on the structure, which needs regular attention.

Brickwork repairs and other works have been required almost annually for a number of reasons, of which more later.

The current works are being undertaken for Network Rail by AMCO, which also undertook some repair work to the viaduct in 2012, following previous repairs by May Gurney (now Kier) in 2009. On a beautiful sunny day, Rail Engineer was shown around the site by Ian Watson, AMCO’s regional manager for the East Midlands, project manager Shaun Trickett, and members of their site team.

Deteriorated brickwork

Twin goals Ian and Shaun described how they are, in effect, working on two agendas. The first is a continuation of the repairs that have been made regularly in the past. The second is the more complex one of strengthening the structure to allow heavy freight trains to pass over it at 60mph, their normal maximum on Network Rail’s infrastructure.

Currently they are restricted to 20mph, and this is inhibiting the infrastructure operator from using the route as a diversionary one for freight trains serving the port of Felixstowe.

The first task is, on the surface, a straightforward one, something which might seem to require simple repetition of what has been done before.

However, this time there are some changes in the remit, the biggest of which is in the scope. Instead of being asked to repair the seriously damaged

areas on the viaduct, leaving less urgent damage to be dealt with at some future date, AMCO has been asked to repair everything.

That makes a lot of sense both economically and in engineering terms, but the most important issue must be the economic one.

The costs of mobilising a team on such a site are high, so it makes sense to do as much work as possible. Also, the land under the viaduct is agricultural and a flood plain, so there are costs in obtaining access over the farmland as well as providing environmental protection, setting-up site facilities and creating access tracks under and adjacent to the structure. All that, and more, before any work can even be started.

The other change is a technical one Network Rail’s requirement to avoid the use of pattress plates on this structure in the way

The repairs to be undertaken were determined by employing Donaldson Associates. A team from its Derby office, under project manager and senior engineer Manesha Pieris together with civil engineering director Peter Harris, undertook the necessary investigations and prepared reports detailing the defects and recommending how to deal with them.

The piers, arches, spandrels and parapets all required significant work to ensure that they could continue to function safely under current loadings, before any consideration could be given to increasing the speed of freight traffic.

The piers were consistently cracked vertically, as well as having some areas of spalled or drummy brickwork and others which needed repointing.

Rail Engineer • August 2016

13

BRIDGES AND TUNNELS

Spalling, and the occasional complete loss of a brick, is prevalent on the arches too. Drummy areas also feature, but the cracking is very much the significant issue affecting the arches.

Some have transverse cracks at the third points suggestive of hinge formation, a serious concern. Most arches have longitudinal cracks, usually a short distance in from each face and apparently directly below the inner faces of the spandrel walls. Many also have a similar crack beneath the centre of the six-foot of the tracks above.

The spandrels have significant areas that are pushing outwards and/or separating from the arch rings, horizontal cracks and often water seepage.

Parapets are of substandard height above the ballast shoulder, many lengths are leaning outwards significantly, and there are a number of horizontal and vertical cracks.

Dealing with the cracks AMCO and Donaldson worked out appropriate repair methods based upon Donaldson’s reports and agreed solutions with the client, Network Rail. These range from conventional repairs, for example repointing, through relatively familiar methods such as stitching and grouting, to some more innovative approaches.

Of particular interest are the parapet repairs. The vertical cracking is being dealt with by replacing bricks that have cracked through, and by installing 6mm stitch bars within the brickwork across the cracks. It is also intended to tie the bases of the parapets more securely to the rest of the structure by means of brackets or stitch bars.

None of that is too unusual, but the approach to the horizontal cracks is more innovative.

The concept of inserting vertical stitch bars is not new but the means of doing so is. Readers of Rail Engineer will have heard of Foulstone

Forge before, in the context of bespoke pieces of equipment. In this instance, it involved a special drilling rig to mechanise and speed up the process of drilling the holes vertically down into the parapets.

The drilling rig is designed to be self-stable once it has been lowered onto the top of the parapet by an RRV. It consists of a frame that holds three drills at the correct centres along the wall and, once aligned, it can drill three holes down into the parapet within three minutes. 20mm bars are inserted and grouted into the holes, and failed bed joints are raked out and repointed to complete the repair.

All of these works are scheduled to be completed by March 2017, at a cost of some ÂŁ7.6 million.

BRIDGES AND TUNNELS

14

Rail Engineer • August 2016

Piers and arches Donaldson Associates also addressed the question of strengthening for heavy freight.

Under the railway system of categorising track and structures by load capability, the viaduct is currently rated as RA0, the lowest possible category, meaning that 25 tonne axle-load freight is restricted to 20mph. This will have to be increased to the maximum (RA10) if freight trains are to be permitted to run at 60mph.

Using arch-assessment software known as Archie-M, provided by Obvis, Donaldson assumed in the analysis that all of the identified structural defects in the viaduct would be rectified. Running the analysis confirmed the current RA0 rating and indicated that, even in a repaired state, the structure would remain at risk of collapse if RA10 loading was applied.

The modelling indicated that the load path in the piers at certain spans would lie outside the pier structure, suggesting collapse would be likely.

A Category 3 check of this work, a third-party design check by an independent organisation, was undertaken by Archie-M developer Bill Harvey Associates and confirmed these findings.

So Donaldson Associates prepared a report suggesting options for the required strengthening to achieve RA10. These were threefold: »» Over-arch reinforced concrete saddles (see above); »» Under-arch strengthening by reinforced concrete arches supported on steel needles through the piers; »» Increased ‘backing’ to the arches, carried out by removing the random rubble fill either side of each arch over the piers and replacing it with mass concrete up to the level of the arch tops.

The first option would add the least dead weight to the structure and have practical advantages including the simple incorporation of new waterproofing and of works to tie in the parapets.

However, it would be extremely expensive, require lengthy blockades and, because it would add depth over the tops of the arches, it would cause problems with vertical track alignment.

The second option would be even more expensive and would add three to four times the extra weight of the first, whilst also

significantly altering the appearance of the viaduct. Practical difficulties would also result, such as the need to construct scaffolding over the river and to deal separately with the waterproofing and parapet works. These last would mean that the need for possessions would probably still be there, negating the advantage that under-arch strengthening might otherwise have offered.

Option three would add less dead weight than option two, but still almost three times that of option one. Like that option, it would allow the waterproofing and parapet works to be dealt with simultaneously, but would require similarly major possessions.

Both the second and third options might well require underpinning to strengthen the pier foundations to handle the extra dead weight and live loading combination.

The complexity of this is such that further work is required for option development and selection to proceed. As a result, Network Rail has deferred the strengthening works to CP6.

Meanwhile, a fibre-optic monitoring system will

be installed beneath the arches of the viaduct using technology developed by the University of Cambridge Centre for Smart Infrastructure, led by Matthew DeJong. The outputs from this system will be validated by conventional deflection monitoring of a sample number of arches.

The results of this monitoring will be used by the project team and Network Rail to develop a preferred strengthening option, which will then be submitted for approval.

In the meantime, Network Rail’s Infrastructure Projects East Midlands civils renewals team based in Derby, led by project manager Chris Chatfield and scheme project manager Jon Batsford, is keeping a close eye on the situation. By maintaining the current speed restrictions, and by responsible asset management, loading on the structure is minimised and well within safe limits. “The structure is still safely carrying daily passenger traffic,” Chris commented.

And a great view those passengers will have too as they cross this spectacular viaduct.

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Rail Engineer • August 2016

PlanningElevArch for amasonry world’s first! arch jacking trial BRIDGES AND TUNNELS

KEVIN BENNETT

Moco Farm bridge spans the currently mothballed railway between Bicester and Bletchley.

Schematic of the bridge lifted by 900mm with the jacks and timber crib stacks clearly visible.

I

nnovation is a tortuous path which requires a great deal of support from a wide spectrum of people. The Department for Transport has recognised the importance of promoting innovation and engages RSSB to manage the dissemination of funding to companies and individuals through its innovation programme. This is a scheme dedicated to funding idea development and facilitating access to live rail proving grounds.

In February 2014, RSSB’s Innovation Programme invited participants to an event entitled “The Avoidance of Bridge Reconstruction”, during which it was estimated that 25 per cent of the cost of electrification is attributed to bridge reconstruction.

Attending this event was Freyssinet, a structural repair contractor, more often than not to be found beneath a highway bridge doing bridge jacking and bearing replacement, concrete repair or cathodic protection. Acknowledging the call from the rail industry for new entrants to help deliver the CP5 expenditure plan, Freyssinet formally set up its Rail Division in 2013 with the aim of developing new solutions as well as transferring skills between sectors.

The Avoidance of Bridge Reconstruction competition was trying to find an alternative to demolishing overbridges, which often becomes necessary when electrification or larger rolling stock needs to be accommodated on a line.

Hundreds of overbridges have been demolished, at great cost to Network Rail which hoped there must be a better way.

Jacking a masonry arch Freyssinet teamed up with Bill Harvey at that event. Bill is a renowned masonry arch expert who already had the idea of how to vertically jack arches, without having a route to market. Freyssinet provided that route - and so the ElevArch® team was born.

Each brick in a masonry arch is held in place by the support offered by the neighbouring brick, so a thrust line develops around the arch and down into the ground. Provided the abutment, wing walls and soil are able to provide an equal and opposite reaction, the arch remains stable. It takes a brave person to contemplate disturbing this most fundamental of structural stability rules, but that was Bill Harvey’s plan.

The team, along with eight other companies exploring totally different concepts, won funding in 2014 from RSSB for a desktop study to explore the feasibility of the concept. In 2015, ElevArch was chosen, with four others, to advance into phase two of the competition - the full-scale demonstrator.

Rail Engineer • August 2016

ElevArch explained So, what is ElevArch? It is a patented technique which involves cutting the arch free from its abutments and wing walls so it can be jacked skywards to enlarge the space below it. The sequence of operations is key to maintaining that all-important thrust line. A horizontal saw cut is made through each abutment just below

BRIDGES AND TUNNELS

A suitable structure was located on the East-West Rail phase 2 route. This is Moco Farm occupation bridge, which carries a live farm access over a mothballed railway that is currently being recommissioned as part of the East-West route between Bicester and Bletchley. It is an unremarkable brick segmental arch bridge, 4.3 metres wide with a 10.1 metre span and dating back to 1850. But Robert Stephenson designed the line and, whilst it is not a listed structure, it nevertheless seems a shame to lose it.

The structures on East-West Rail phase 2 need an average of about 900mm extra headroom beneath them for the OLE and kinematic envelope. The traditional options are bridge reconstruction and track lowering and, if the ElevArch trial works, 10 similar bridges on the route are possibly suited to the technique as well. Other lines look promising for exploiting the technique too, such as west of Leeds on the Trans-Pennine project and the Midland main line.

17

Southern abutment at Moco Farm showing the bridge and the existing track. the arch springing in conjunction with coring five holes horizontally into each abutment. Vertical lifting jacks are inserted into these holes and they support the weight of the bridge.

The horizontal component of the thrust force is taken by four vertical slip bearings which are inserted into slots cored through the four wing walls. These bearings prevent the arch from spreading horizontally whilst allowing vertical movement. Once they have been grouted in place, it is safe to wire saw cut the rest of the wing walls to free the arch from the foundations and the magic can begin.

The 50 tonne capacity jacks are computer controlled from a central unit to within 0.1mm of each other, thus guaranteeing a fully balanced synchronous lift. In late September 2016, Moco Farm bridge will be jacked 900mm into the air. As the jacks lift, hardwood timber crib stacks will be inserted beneath the jacks to support the bridge each time the jack foot retracts. The lift will take about six hours, during which constant monitoring will verify that the arch is behaving as predicted.

The arch will then be lowered by 465mm so that re-profiling of the approach ramps is unnecessary for the trial. Thus the bridge will be

Rail Engineer • August 2016

BRIDGES AND TUNNELS

18

Brickwork repairs will be necessary before the bridge can be lifted.

left 435mm higher than the starting position and the gap in the abutment where the bridge has been lifted will be faced with brickwork and flooded with concrete to restore permanent support so the jacks can be recovered for reuse. The bearings are left in the wingwalls with the saw cut grouted up having first had the facing brickwork made good.

An additional option The methodology has been developed to minimise the intrusion into the rail environment as much as possible. A bridge reconstruction or track lower can often require several days of railway closure. With

ElevArch, in most situations, there will be a Rules of Route possession to erect the trackside safety barrier and another to remove it at the end. The jacking is intended to take place early on Sunday morning in another Rules of Route possession as it will only need about six hours to complete the lifting operation.

The coring, sawing, grouting and other tasks can all take place from behind the barrier using relatively light equipment. So, not only are the direct costs of this technique expected to be significantly less than bridge reconstruction or track lowering, but the demands for track time will be reduced as well. It is also perceived to

be less risky as there is no need for a large crane with all its access and weather susceptibility issues.

The ElevArch technique is not expected to replace bridge reconstruction or track lowering completely, but rather join that pair as a third option to be selected by the engineer as the solution when the situation is most appropriate.

It is expected to be of significant interest in heritage situations when track lowering isn’t viable - it’s better to sympathetically move a heritage structure than remove it altogether.

With something in the region of 500 overbridges getting in the way of Britain’s electrification programme, the future for this bold but simple technique is expected to be bright.

Kevin Bennett is sales and technical director, Freyssinet.

Freyssinet wish to acknowledge the tremendous support given by the East-West Rail team in bringing this concept to trial.

Anyone interested in attending the open day and witnessing the world’s first ElevArch trial in September should contact John Kennils at john.kennils@freyssinet.co.uk.

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Rail Engineer • August 2016

NIGEL WORDSWORTH

Lateral thinking in Lincoln

F

ootbridges are simple structures, and so is installing them. A few concrete pads, two steel lattice towers - prefabricated off-site, a couple of staircases, and a steel bridge deck that can be lifted into place overnight while the railway is closed.

The only option was to purchase, then partially demolish, the rectangular brown building next to the railway.

Simple - and quick.

Except…bridges now have to be accessible to wheelchairs, young children in buggies and heavy luggage on wheels.

No problem - just replace the two staircases by gently sloping ramps.

Except…a footbridge deck is typically 6.5 metres above the ground. With a 1:12 gradient, the steepest allowed, that means the ramps have to be 78 metres long. Even folding them back on themselves and its still around 40 metres long. That’s a lot of space that’s needed.

OK then, so go for lifts instead.

That solution means concrete lift shafts, winding gear or hydraulic rams, a substantial electrical supply, pits under the lift shafts, fail-safe control gear, 24/7 monitored help line and still quite a bit of space.

Suddenly, it’s not as simple as it seemed.

And what if there is no space - even for a simple footbridge?

“Most dangerous” A case in point is the project to build a footbridge, on High Street in Lincoln, to provide pedestrians with an alternative route across the railway other than the existing level crossing.

35,000 pedestrians and cyclists use the crossing every day, and so do over 140 trains.

People are often seen running over the crossing once the lights sequence has begun, and even when the barriers have started to lower. CCTV footage taken from January this year shows a woman fall as she attempts to run over the crossing before the barriers close.

This misuse has resulted in the crossing being rated as number one on the level crossing risk register for the London North Eastern and East Midlands route, and one of the top five most dangerous crossings in the UK. © Google

Network Rail therefore contracted Galliford Try to build a footbridge, complete with a lift at each end, to give pedestrians a safer alternative when the crossing gates were shut.

The first challenge was - where to put it? With buildings on both side of the road on the northern side of the railway, there was no obvious place.

Enter the lateral thinkers from Network Rail. If the buildings are in the way, then buy one of them and knock it down.

So that was what happened. Network Rail bought the former Sleep Shop building on the east side of the road and demolished the front third of it. This gave room for the bridge - the other side of the tracks was conveniently vacant next to a multi-story car park.

Rail Engineer • August 2016

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Demolition

BRIDGES AND TUNNELS

Commencing June 2015, the front bay of the three-storey building was demolished to create space for one of the abutments. During the process, asbestos was discovered on the concrete roof structure under the bitumen coating. At first, the team from Galliford Try attempted a scraping technique to remove the asbestos but, within hours, ceased the operation as air tests showed that safe working limits were being approached.

Following consultation with the Health & Safety Executive (HSE), an alternative technique was employed.

The roof beams that contained the asbestos, each weighing 25 tonnes, were encapsulated in a glue-like liquid and plaster of Paris wrap and then lifted out by a 250-tonne road crane during an overnight road closure and nine-hour overnight rail possession last December. The beams were too large to remove directly from site for disposal, so were cut into two within an encapsulation tent.

Thereafter, a remote-controlled Brokk robot was used to demolish
the front of the building, working from the third floor down. Brokks are ideal for demolition in confined spaces, and the

use of larger plant was also unviable because of the close proximity of the site to the railway line. The contractors could not risk disturbing the track or allowing any debris to fall onto it.

Construction With the site cleared, construction of the bridge towers could begin.

Well, almost. On investigation, the site was found to be riddled with services - 57 operational cables for signals, power, telecoms, points, heating and so on that needed to be relocated before work could begin.

Once the site was finally clear, piling for the tower foundations could start.

Forty 273mm piles were driven down to a depth of eight metres, topped off with hefty concrete ground beams to support the structures. Lift pits were dug, 2.5 metres deep, and lined with concrete.

(Above) Removing asbestos-contaminated beams during demolition.

(Inset) The second tower is lifted into place.

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Rail Engineer • August 2016

BRIDGES AND TUNNELS

The steelwork for the two towers was lifted in during three Saturday night possessions from late January, as was the 21-metre lattice-girder bridge deck which had been manufactured in Doncaster by Carver Engineering Services.

Once the steel steps were also in place, the towers were clad, using the bracket and rail cladding system, in weather boarding, Kingspan insulation board and then, after all of the cabling had been fitted, a final layer of Shackerley composite stone cladding.

Stannah lifts and associated hydraulics were installed in April, as were the glazed balustrading and handrail.

All of the concrete pouring and crane lifts had to take place during Saturday night possessions for safety. The cladding and the glazing of the balustrade, however, could be carried out in normal working hours.

The glazed balustrade is unusual. City planners didn’t want the bridge to look too imposing, so the glass was specified to give it a light, almost invisible, appearance.

Opening

(Below) The bridge takes shape.

(Inset) The glass balustrade gives a good view of the station.

Safety was so high on the agenda at High Street that the bridge was opened as soon as it was safe to do so, even before it was completely finished. Three weeks of late-night closures were required after the actual opening, during which the lifts were also brought into service.

“The bridge has been a challenging but satisfying project to undertake,” commented Wes McKee, rail director at Galliford Try, “because of the amount of night work and the complexities of getting plant and materials, particularly the steel bridge sections, to site in such a busy, central location.”

Rob McIntosh, route managing director for Network Rail, added: “Safety on the railway is our absolute priority and building a footbridge on this scale, in such a heavily used and built up area, has presented lots of challenges, but

we have never wavered in our commitment to deliver this footbridge and separate pedestrians and cyclists from trains at High Street level crossing. What we need now is for people to use it, to make it part of their daily routine, and not take a chance by running over the crossing when the barriers are closing.”

Legacy But what of the part-demolished building that still stands alongside the new bridge? Network Rail has now received planning approval to demolish the remainder of 179 High Street and replace it with student accommodation in conjunction with joint venture blocwork LLP. As part of this development, a pedestrian route will be provided through Wigford Yard, better connecting the University campus and its new faculty building with this part of High Street. blocwork is a joint venture between Network Rail and bloc, established to maximise value from under-used property assets next to the railway. Generation of profits by the partnership will help contribute to the upkeep and renewal of the rail network.

Be that as it may, Lincoln now has a shiny new footbridge to keep its pedestrians safe and away from any temptation to take a gamble with their lives, which must be a job well done.

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Rail Engineer • August 2016

Bermondsey Dive Under Removing another critical pinch point!

BRIDGES AND TUNNELS

COLLIN CARR

T

he Thameslink Programme is now reaching its final stages. Despite this, demands on the engineers involved are certainly not getting any easier. Network Rail is now working through the process of untangling the complex track layouts on the approaches to London Bridge station to enable train operations to run more efficiently.

A major objective of the Thameslink Programme is to provide additional services through central London and reduce delays outside London Bridge station. To do this, two pieces of infrastructure are absolutely vital. One is the new viaduct at Borough Market, which provides for an additional two tracks at this otherwise-critical pinch point. The other is a grade-separated junction between New Cross/New Cross Gate and London Bridge station.

As it was - track layout in 1908.

This is an essential requirement that will enable trains travelling from the South East to reach Charing Cross without conflicting with trains from the Brighton line going to Blackfriars and beyond.

This grade-separated junction is enabled by a structure known as the Bermondsey Dive Under and, in May 2012, Network Rail awarded a ÂŁ75 million contract to Skanska to design and construct it.

Additional challenge The site for the Dive Under is located about a mile away from London Bridge station on its eastern approach. It will allow the Thameslink lines to cross over the Kent lines, unimpeded on their approach to London Bridge station. This will help to ensure that Network Rail is able to provide infrastructure for up to 24 trains per hour to run through London Bridge and travel north on the Thameslink route.

Throughout the work, one of the main challenges for Skanska has been the ability to carry out this complex programme of work whilst minimising disruption to the dense train service travelling through this location. It is not a job for the faint hearted.

The main construction works were started in 2013 and the plan is to complete the work by spring 2017. There are, in fact, two parts to the contract. In addition to the construction of the Dive Under itself, and following Network Rail completing the assessment of more than 50 structures in the vicinity, 20 bridges were identified as needing strengthening and Skanska is undertaking that programme as well.

Rail Engineer • August 2016

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BRIDGES AND TUNNELS

This work is primarily associated with wheel timbered decks that require strengthening and converting to ballasted track. Each bridge is different and the strengthening work quite challenging.

Skanska has also reconstructed a three-span steel bridge in an interesting way. The two outer spans have been filled with foam concrete to just below the soffit of the existing decks. Then the decks have been removed and a concrete capping slab installed, waterproofed ready to receive ballasted track.

The central span has been removed and a concrete U shaped structure constructed. A rare 50-tonne forklift truck was used to install the 24-tonne precast units forming the deck of the new bridge. Skanska’s engineering manager, Julian See, explained that the team are very proud of this work which has been designed and built in 18 months and was a precursor to diverting services and obtaining the BDU site.

Skanska appointed Ramboll Consulting Engineers to assist with this bridgework and to work with Network Rail to finalise the design of the Bermondsey Dive Under box structures.

Returning to the Dive Under The Dive Under consists of two new ramps carrying the Kent lines travelling from east to west. These lines will drop down and travel through a concrete box. A new embankment carries the Thameslink lines from the south east over the box and down a ramp on the west side. Similarly, the Kent lines that travel through the box then return along another ramp up to normal ground level, thus enabling Thameslink trains and Kent trains to swap over without incurring any delays. It’s all quite simple really, once enough space has been created, and that has been one of the key challenges.

In order to clear the space for the concrete ramps, reinforced earth embankments and concrete box, contractor Armac demolished more than 100 brick arches. Concrete ‘bookends’ were constructed around specified piers to ensure that the demolition of one arch didn’t create a ‘pack of cards’ failure.

A box not a tunnel More than 500 metres of precast arches - 71 new arch spans - are being constructed to replace old ones and to form the new alignment (below). The material from the demolished structures is being recycled and used in the new earth embankments using two crushers on site.

The concrete Dive Under box itself is 155 metres long. Kevin Sullivan, the programme manager for Network Rail, pointed out that, because of its length and design, the box is not classified as a tunnel. If it had been, then there would have to be several additional key interoperability features included within the design.

During the early stages of the project, Skanska installed three large steel span sections onto four reinforced concrete piers which had been previously constructed over the East London Line. Once these beams had been lifted in using 500 tonne and 250 tonne cranes, 30 precast concrete L-shaped units were fixed onto the steel structures, secured by 1,000 shear studs that were welded on site.

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Rail Engineer • August 2016

BRIDGES AND TUNNELS

The designers claimed that this solution will also reduce long-term maintenance requirements since expansion joints are eliminated as the arch structures are in compression.

The concrete arch segments were designed to have a similar stiffness to conventional masonry arch rings. They have a structural concrete backing with a curved upper profile, as typical arches, and were then filled with foam concrete in two layers. Careful thought was required regarding the performance of the fill material so that the arches behave in a similar fashion to long lengths of masonry arch viaducts that ‘breathe’ under loading.

Open lines

(Above and below) Removing the old steel bridge.

This work, which took place alongside the brick-arched viaducts that carry six main lines, formed the start of the transitional structure that now spans from the existing brick viaduct to the Bermondsey Dive Under. This was followed by the demolition of 35 arches and track slewing by Balfour Beatty so that work could start on the construction of the Dive Under box. Around 400 of the 760 continuous flight auger (CFA) piles that have been installed on the site are for supporting the reinforced concrete box structure.

Precast arches An innovative part of the design developed by Ramboll was to use a precast arch solution in place of the one developed during the outline design stage, which was for reinforced in-situ concrete portals.

One of the benefits of the arch structure proposal is that the form of the new arches is in sympathy with the existing masonry arches, ensuring that the load distribution on the foundations remains relatively unchanged. It has allowed many of

the existing piers to be reused and, as a consequence, it has contributed significantly to reducing the number of piles and eliminating the requirement for low-headroom piling, thus ensuring that the same piling rigs could be used throughout the project.

The precast arch design also uses a constant arch radius, meaning that the arches could be cast and constructed off-site. This, in turn, ensured that quality standards were maintained and that work on site was kept to a minimum - a significant issue in a blockade and one which significantly reduced site safety risks.

Stobart Rail has been busy on several elements of the project.

These have included removal and reinstatement of track, excavating fill from the arches, the placement of steel cages and framework, constructing concrete saddles over arches to strengthen the structure, forming robust concrete kerb and various waterproofing and drainage works. Many have been undertaken with the adjacent line open and much of it was accomplished in only 28 days, working 24/7.

Neil Bishop, Network Rail’s construction manager, was obviously impressed with the work carried out. “I was out on site frequently,” he commented, “during which time I was able to observe the machine controllers, drivers and COSS’s carrying out the works and it was clear from their actions and subsequent conversations with them how serious and professional they were in relation to this challenging element of working adjacent to the open lines.”

Rail Engineer • August 2016

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Bolina Road

BRIDGES AND TUNNELS

An added complication in the project lies in the fact that Bolina Road, a small single lane roadway, crosses the site from north to south at a point just before the different lines enter or fly over the Dive Under box structure at the east end. The existing steel bridge offers limited head room for vehicles and proudly displayed a series of bullet holes from the Second World War. It was ready for retirement!

To bridge the gap, the site team constructed five in-situ bridge structures at different stages in the project. Four of the five bridges are simple reinforced concrete structures and are well advanced, which has helped with plant movement on the site. A steel-decked span is being constructed over the roadway which is being converted into a walkway and cycle path.

A major constraint on construction resulted from the need for the centremost two bridges to straddle the road, while giving adequate clearance for the Bolina Road path. Track on the bridges also had to be aligned to meet the

horizontal constraints imposed by the alignment of the box with the existing track.

It is a complex and difficult undertaking and one that has been sidestepped over the years. As Julian stated: “Everything is interrelated and it all has to be done at the same time�. The location is also extremely challenging and any delays caused by completing this work have the potential to create major concerns.

Having said that, walking round the site there appeared to be a very calming atmosphere, order was evident alongside a sense that everything is going to plan.

There have not been any reportable accidents in three years. This all suggests that another critical pinch point will soon be removed, moving Network Rail even closer to a Thameslink route fit for the twentyfirst century.

The 24-tonne precast units that will form a new bridge deck were positioned using a 50-tonne fork lift truck.

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Rail Engineer • August 2016

BRIDGES AND TUNNELS

TIM BURGESS

Bedford’s

Bypass Bridge All photos © Breheny Civil Engineering

Considered solution

(Inset) Construction starts, with the railway as-yet untouched.

(Right) An East Midlands Trains' Meridian service passes the construction site shortly after work began.

T

he northern section of the Bedford Western Bypass was officially completed and opened by the Mayor of Bedford Borough on 25 April 2016. The bypass has featured in local and national plans for over 30 years, with the first southern section linking the A421 to the former A428 completed in 2009, the second northern phase then linking the A4280 at Biddenham to the A6.

The new route permits traffic travelling from the north or south to travel round the perimeter of Bedford, alleviating congestion in the busy town centre. It also opens up areas for 1,200 new homes, affordable dwellings and an employment park for 650 new jobs.

A significant obstacle on the northern section was the crossing of the Midland main line, which serves as the only primary route between London St Pancras station, the East Midlands and parts of South Yorkshire. It was therefore vital that the proposed bridge had minimal impact on the daily operation of the railway line.

The design would have to be both future-proof and low-maintenance, and provide access by road, cycle and utilities to the adjacent development land. At this location, the bypass would be a single 9.3 metre wide carriageway and 3.5 metre cycleway crossing the four railway lines (Up/ Down Fast and Slow).

The main contractor for this £18.6 million scheme was Breheny Civil Engineering, along with subcontractor MPB, for Bedford Borough Council.

Tony Gee and Partners was responsible for civil and structural designs for various structures on the scheme, working with lead designers Waterman Infrastructure and Environment.

Tony Gee had been involved with the project since its inception back in 2006, developing conceptual designs for the railway crossing at an early stage, with close liaison with the council, design team and the relevant authorities, through to detailed design and eventual construction in 2014.

Various construction forms were considered during the initial design stage with regards to the buildability and impact on the railway. A 48 metre long single-span composite weathering steel bridge without splices, supported on two in-situ concrete abutments, was considered to be the best solution.

The construction depth of the deck and carriageway alignment was optimised to minimise the extent

Rail Engineer • August 2016

BRIDGES AND TUNNELS

of fill required to form the abutments, which were to be built up from grade. 80 per cent (90,000 cubic metres) of the fill was site-won material, excavated from three new drainage attenuation ponds forming a new country wildlife site. The design also catered for future overhead electrification of the railway line north of Bedford to Sheffield in respect of the minimum headroom clearances required.

The stratigraphy at this location consists of large areas of limestone and mudstone at relatively shallow depths. This sound formation permitted the abutments to be constructed on spread footings distributing the loads rather than using piles. The length of span and geotechnical conditions precluded the use of an integral bridge abutment; however the longer span configuration permitted all works associated with the abutments (some 1,200 cubic metres of concrete) to be constructed outside of the operational railway land.

The deck was supported on 1.85 metre deep, 50 metre long weathering steel girders weighing 45 tonnes each with plate thicknesses up to 60mm. The detailing considered potential moisture traps, and run-off plates were provided to prevent moisture migrating back to the bearings to avoid rust staining and increased corrosion.

Weathering steel was selected to maximise the longterm durability of the structure. The naturally forming rust patina provides 120-year design life and mitigates the potential costs associated with the maintenance of protective coatings over the busy railway.

29

The girders were designed and detailed to be erected in k-braced pairs weighing over 100 tonnes. The combined weight and design of the girders was limited by the maximum reach of a 1,000 tonne mobile crane, with 300 tonne superlift ballast, situated to the side of the railway so that they could be quickly installed during limited railway possession hours.

Between 160 to 180mm of pre-camber was applied to each girder at fabrication to mitigate the large self-weight deflections, and careful consideration was required on installation to ensure the tapered bearing plates on the soffit landed in the correct positions.

The 1,000 tonne crane lifts one of the main beams prior to installation over the railway.

Rail Engineer • August 2016

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(Above) With the main bridge deck in place over the railway, (Inset) work can start on the approach ramps.

(Right) The result of 10 years' planning.

Truck-proof deck The 250mm thick 300 cubic metre in-situ reinforced concrete deck was formed using permanent GRP formwork to provide an instant working area. With the approval of Network Rail, this permitted deck construction to progress during continued operation of the railway.

The edge girders were also preinstalled with cantilever working platforms, providing soffit formwork for the copings and handrails to provide instant access. The platforms reduced the requirement for further lifts and work at height.

The deck also contains multiple service ducts for future utility connections to the adjacent development land. In accordance with the DMRB (Design Manual for Roads and Bridges) durability requirements, the structure also contains stainless steel

reinforcement in exposed areas, such as the parapet copings and the bearing plinths, to minimise the extent of future maintenance and to provide an asset that will last for the required design life.

The deck copings support H4a very-high containment parapets on either side, capable of withstanding

impact from HGVs, with anti-climb plates to the rear and top hat copers. The parapets tie in with transitions at each end to the adjacent vehicle restraint system to prevent errant vehicles leaving the carriageway and finding their way onto the track.

Whilst the bridge is, perhaps, not remarkable for its geometry and form, the project has been able to progress without problems due to the careful planning of the construction method and design detailing, minimising its impact on the existing infrastructure and public.

The team at Tony Gee and Partners was very pleased to have been involved in the scheme and to have the satisfaction of seeing it built -10 years after its original conception.

Tim Burgess is principal engineer at Tony Gee and Partners

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Opposing Forces Rail Engineer • August 2016

B

ox-ticking is a fact of life we’re all familiar with. No matter how routine, managerial decisionmaking is propped-up by paperwork for those rare occasions when investigators need an audit trail to follow. It often seems disproportionate, but such is the shadow cast by our legal system.

Nowhere has bureaucracy felt more onerous than in the realm of product approval, justified by the need to avert uncontrolled risk. This isn’t a recent affliction though; those in authority have been rightly asking questions since the railway’s early days.

Box girders are standard design tools for today’s civil engineer and, as such, their history is rarely given much thought. The first major railway structure to employ them - straddling the Nottinghamshire-Lincolnshire border at Torksey - still stands as a notable landmark in time and space. So ground breaking was it that the regulator initially refused to sanction its use.

A vigorous technical skirmish ensued with the engineering fraternity, both sides fearing the reputational damage that being proved wrong might inflict. The result was a four-month standoff accompanied by mudslinging.

GRAEME BICKERDIKE

Grand designs Largely responsible for development of the box girder was Kelso-born engineer William Fairbairn, working alongside mathematician Eaton Hodgkinson. In the late 1830s, these longstanding collaborators revealed an optimal design for a riveted wrought-iron plate beam which, in the context of bridge applications, incorporated cells at the top to help resist compressive forces.

Soon after the pair’s work was published, proposals emerged for the Chester and Holyhead Railway which demanded two substantial bridges, over the River Conwy and Menai Strait. These were advanced under the stewardship of chief engineer Robert Stephenson who put forward the idea of constructing the spans as wrought iron tubes. He retained Fairbairn and Hodgkinson

as consultants, asking them to consider the practicalities. In April 1845, a series of experiments began on large-scale prototypes, mostly carried out at Fairbairn’s shipyard in Millwall. Hodgkinson validated the conclusions through calculation.

Opened on 5 March 1850, the Menai Strait crossing - known as Britannia Bridge - was a pioneering structure of great proportions. Its two central spans each extended for 460 feet and weighed 1,500 tons; with the side spans, these formed a continuous girder of 1,511 feet, rectangular in section and large enough to accommodate the trains within it. Until then, the longest wrought iron span had been just 31 feet 6 inches.

Rail Engineer • August 2016

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Ultimately, Stephenson’s tubular girder bridge concept proved too costly for widespread adoption due to the volume and hence cost - of the materials needed.

But it did inspire another engineer to take things in a slightly different direction.

BRIDGES AND TUNNELS

Boxing clever

A shoddy accusation Work on the viaduct was completed late in 1849 and Captain Lintorn Simmons of the Royal Engineers attended on 21 December to inspect it for the Board of Trade. Formal authority to open was a requirement of the Railway Regulation Act 1840 which brought into being the Railway Inspectorate.

(Above) A very early photograph of Stephenson’s Britannia Bridge across the Menai Strait, taken circa 1860.

(Right) A cross section through one of its 1,511-foot tubular girders.

Simmons tested the girders by arranging for two locomotives and tenders to be brought onto each track above one of the spans. The deflection was measured at almost 1¼ inches. This was “more than might, I think, have been anticipated,” he remarked; the riveting “appeared not to be very perfect” and the girders themselves were “not built in a very accurate line, nor very regular in form.” Based on these observations, it was concluded that the structure presented “danger to the public using the same, by reason of the insufficiency of the works.”

Approval was therefore refused until strengthening work had been undertaken.

© Wellcome Library, London

The Manchester, Sheffield & Lincolnshire Railway established a link between Liverpool and Grimsby through the first Woodhead Tunnel. Its directors enjoyed an inaugural trip between the two ports on 16 July 1849, passing six miles west of Torksey Viaduct which their company was building as part of a line connecting Retford to Lincoln. Engineering it was John Fowler, remembered today for constructing the earliest parts of central London’s underground network and as co-designer of the Forth Bridge.

Crossing the River Trent, the viaduct featured a timber approach structure on its east side - 570 feet in length with two 130-foot clear spans over the water supported by a central masonry pier. Each span comprised pairs of wrought iron box girders measuring 10 feet high and 2 feet 3 inches wide, with two cells at the top. The deck plates and tracks were carried on cross beams at two-foot centres.

(Below) The two main spans of Torksey Viaduct, crossing the River Trent.

PHOTO: FOUR BY THREE

Rail Engineer • August 2016

© Four By Three

BRIDGES AND TUNNELS

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The potential consequences of design and constructional deficiencies were well understood by Simmons, having investigated the fatal collapse of a bridge over the River Dee, one of Robert Stephenson’s lesser structures on the Chester-Holyhead route. It was concluded that the main cast iron girder had been substantially weakened by repeated flexing due to traffic loading. As a consequence, it broke in two places as a train passed over.

The accident prompted a government inquiry into the use of iron in railway structures, a substantial contributor being Eaton Hodgkinson, who derived an empirical formula for establishing the concentrated load at which a cast iron beam would fail. It was also recommended that such a beam should not be subjected to a live load exceeding onesixth of that breaking weight.

© Wellcome Library, London

Unto the breach, dear friends

(Above) Yorkshire-born Sir John Fowler is credited with building the world’s first underground railway in London, as well as designing the Forth Bridge alongside Benjamin Baker.

(Right) Sir John Lintorn Simmons, photographed in 1896, by which time he had risen to the rank of Field Marshal.

(Top) Inside one of the cells at the top of Torksey Viaduct’s main south girder.

For the MS&LR, the commercial implications of Simmons’ decision on Torksey Viaduct were obviously damaging. Fowler wrote to him, pointing out that he had erroneously taken the weight of the four locomotives used for testing purposes to be 80 tons when they were actually 148 tons. Simmons recalculated, asserting that “the conclusions at which I before arrived still remain unshaken.” Another trial was arranged, this time resulting in a deflection of 1.26 inches from a load of 223 tonnes (six locomotives), but Simmons would not be moved.

Much indignation was apparent amongst Council members at the Institution of Civil Engineers when the matter was brought before them. Charles Vignoles made it clear that previous “legislative interference” experienced by him had been “extremely obnoxious.” John Scott Russell asserted that “for some time past, there had been many attempts to restrict the free exercise of the talent and ingenuity of engineers.” He was especially animated by Simmons’ apparent application of Hodgkinson’s formula “to a new system of construction (wrought iron tubular girders) for which it had never been intended.”

Whilst conducted with appropriate formality, the exchange of letters between Simmons and Fowler had a distinctly prickly tone as each attempted to dismantle the other’s argument.

It’s worth making the point - as Simmons readily acknowledged - that neither could claim any expertise as only Fairbairn and Hodgkinson had accrued much genuine understanding of the subject. As such, it became a little like two bald men squabbling over a comb.

Rail Engineer • August 2016

On that bombshell

safe compressive strain”. However Simmons pointed out that this was based on a girder without joints. But Fowler then pulled a rabbit from his hat, claiming that the bridge - without any alteration - already complied with “his extraordinary requirements”, as Simmons had failed to account for the girder being continuous across the two spans. This, according to Fowler, “imparted additional strength to the bridge in the proportion of 9 to 14.” Stumped, Simmons retorted that continuity

had “never been urged upon me…as an important element in the consideration of the bridge,” despite “a casual reference” being made to it during one discussion.

Back at the Institution, engineers Charles Wild and William Pole were independently attempting to validate Fowler’s investigations on the benefits of continuity one through experiment, the other by calculation. They both concluded that, as the bottom plate was subject to compressive forces over the central pier, but

was in tension elsewhere, the girder could be regarded as three independent beams, divided at the points of contrary flexure. Using this approach, it was determined that the effective length of each span should be regarded as ~108 feet, not 130 feet. With the required load of 400 tons reduced in proportion, the greatest compressive strain on the top plate could then be calculated at ~4.6 tons per square inch, less than the limit stipulated by Simmons.

164 tons

ABUTMENT

400 tons

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ABUTMENT

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BRIDGES AND TUNNELS

Eventually Fowler cut to the chase, asking Simmons to specify what further strengthening the viaduct needed. He responded that a load of 400 tons over one span - including the 164-ton weight of the structure itself - should not produce a pressure on the top plate of more than five tons per square inch.

Fowler protested strongly at this as Eaton Hodgkinson had, in his view, determined that eight tons per square inch was “a perfectly

35

Rail Engineer • August 2016

BRIDGES AND TUNNELS

36

© Four By Three

(Right) Grit-blasting the cross beams.

Offensive retreat It isn’t hard to imagine the frosty atmosphere when, on 26 March 1850, Fowler, Pole and Wild met Simmons and his colleague, Captain Laffan, on the viaduct to demonstrate their findings. This was done by fixing a telescope to the western abutment, lining up its crosswire to a horizontal mark on the eastern side, then loading one span with nine wagons - totalling 144 tons - and reading off the deflection from a graduated staff. Measurements were taken at 10-foot intervals across the structure and compared with theoretical figures, the largest deviation proving to be just 0.13 inches.

Simmons’ hand had been forced, leaving him with little alternative but to authorise the line’s opening. In doing so, he restated his disagreement with many of Fowler’s observations and, as a parting shot, insisted that the depth of ballast over the viaduct must not exceed two inches in order to minimise its loading.

Charles Manby, secretary to the ICE, voiced the profession’s collective displeasure at the fourmonth “arbitrary” closure imposed by Simmons, condemning “the employment of officers who possessed undoubted skill for their own peculiar military duties, but who were placed in a false position when they were entrusted with the execution and control of civil works.”

Different times All this proved a momentary distraction for Simmons. Three years later, whilst on leave in Turkey, the British Ambassador requested that he report on the country’s ability to resist a Russian advance. Then the Crimean War started.

In 1854, he became British Commissioner with the Turkish Army, playing a prominent role in several battles. His distinguished military career culminated in promotion to field marshal in 1890.

An evolution had changed the face of Torksey Viaduct by the turn of the twentieth century. In 1877, the timber approach structure was replaced by cast iron screw piles supporting wrought iron girders whilst, 20 years later, the main spans were stiffened by moving the southern girder outwards to create space between the tracks for a pair of Pratt trusses. How telling is that?

A train last tested Fowler’s work in 1959.

Closure brought deterioration with it and, despite a Grade II* listing, the structure recently found itself on the Heritage at Risk register. However two £200,000 grants from the Railway Heritage Trust paid for Hankinson Group to grit-blast and repaint the north-side ironwork in advance of a footpath being laid over it by Railway Paths, the viaduct’s current custodian. This was formally opened in April 2016.

© John Litt

(Above) The viaduct’s Pratt trusses dominate the scene at the footpath’s formal opening.

Further afield, Britannia Bridge was damaged beyond repair on the evening of 23 May 1970 when two boys - playing inside it - dropped a burning torch and set alight the tar-coated timber roof. It was rebuilt to an arched design by Husband and Company, later acquired by Mott MacDonald; rail traffic resumed in January 1972.

Stephenson’s other tubular girder bridge over the River Conwy continues to carry trains on the North Wales Coast line.

Regulators have a duty to challenge innovators, but don’t have the right to stifle them. When it came to box girders, officialdom was overcome by the great Victorian engineers who wielded considerable clout; too much of it perhaps. Today the tables are turned, driven by an institutional fear of the unknown. The extent to which that disadvantages the industry as it strives to reduce costs and improve efficiency is something that should be determined.

Did Hodgkinson have a formula for that?

Rail Engineer • August 2016

37

BRIDGES AND TUNNELS

New footbridge old design

BOB WRIGHT

T

he North Norfolk Railway’s headquarters at Sheringham is a two platform station, generally operated as a terminus although, since its 2010 re-connection, occasionally as a through station onto the national network. The original 1897 footbridge was demolished in the early 1960s when British Rail services were withdrawn.

During the last 51 years, the North Norfolk Railway has used a supervised foot crossing of the tracks to provide access to Platform 2. This is not ideal, and it has long been an aspiration to install a footbridge.

Over the years, Network Rail has offered the railway a number of redundant bridges. However, old lattice bridges are often in poor condition and are not easy to repair satisfactorily.

Build a new one In 2015, a public appeal was launched to finance a new-build bridge at Sheringham as well as one at the railway’s other terminus at Holt. Contrary to expectations, the railway’s supporters and local residents were keen to contribute towards something as mundane as a footbridge and the target was soon reached.

It was decided to recreate the original bridge as closely as possible. Using the 1897 Midland & Great Northern Railway’s drawing as a starting point, NNR’s designer Luxford Harrison designed the structure to current Eurocodes.

The structure was analysed using 3D analysis software, with every individual member modelled.

It was generally possible to use modern equivalent sizes to the original members, although it was necessary to utilise slightly larger sections in the U frames, partly to resist the pedestrian and wind loadings to the parapets specified

by Eurocodes. Some modifications to the width of the structure and step rise and going were made to bring the structure in line with current standards.

Fabrication drawings for each member were produced by the author, acting as the NNR’s voluntary civil engineer!

Milne Partnership, the NNR’s fabricator, normally works with large section members and welded structures. These all-bolted, small section, lattice girders provided a different challenge. A total of 670 individual members were manufactured, fastened by 800 bolts - a clear reminder of why simple welded-plate girder footbridges have become the norm in non-heritage industry railway projects.

The maintenance of lattice structures is difficult, with many potential water and detritus

traps. To minimise future deterioration, the whole structure was galvanised and painted with an RT98 M20 epoxy paint system.

Following erection at the beginning of June, the railway’s employees have installed timber decking and stair treads and also strained stainless wire lines to reduce the opening sizes to prevent falls.

The new bridge has met the objective of providing a modern bridge that maintains the appearance of the original bridge, and all for a very modest £70,000 too.

BRIDGES AND TUNNELS

38

Rail Engineer • August 2016

Port Talbot

showcase BOB WRIGHT

P

ort Talbot Parkway began life in 1850 simply as Port Talbot station, acquiring its latest name in 1984. It serves around half a million passengers each year, with services by Arriva Trains and GWR to Swansea, West Wales, Cardiff Central, Newport, London Paddington and Manchester Piccadilly.

As part of its Wales Station Improvement Scheme, Network Rail planned to invest £10 million to improve facilities at the station, including the ticket office, waiting area, customer facilities and car parking, incorporating step-free access for passengers, all common across the network.

However, something much grander was proposed for Port Talbot Parkway.

Celebrating steel While Port Talbot has been in the news in recent months with its steelworks under threat of closure by Tata Steel, the town had a confident 110-year history of steel production when the project was being developed in 2011.

The Welsh Government, Network Rail and Tata took the opportunity to create a new station footbridge that would act as a high-profile example of the architectural use of steel.

The project was funded by the European Regional Development Fund, Welsh Government, Department for Transport, Network Rail, Neath Port Talbot County Borough Council, Arriva Trains Wales and Tata Steel.

At the time, a spokesman for Tata Steel said: “We are providing some 185 tonnes of structural steel and 1,145m2 of strip steel. That locally-made steel will play such an important role in Port Talbot Parkway demonstrates the continued strong bond that exists between the steel industry and the community.”

Port Talbot Parkway has a single island platform with up and down avoiding lines serving the route’s heavy freight traffic. The existing footbridge spanned from the north side to the platform. Access to the south was via the nearby Oakwood Lane level crossing. The proposal was for a new footbridge with a 26 metre span from the platform to the

Rail Engineer • August 2016

Preparing the lift Site agent Adrian Fox found the erection of the structure a challenge. Rules of the route possessions were available for preparatory works, including the structural steel central lift shaft and fin wall. The placing of the new steel structure was restricted to just two 12-hour disruptive possessions. The size and weight of the structure and the radii involved - the

fuselage weighing in at 213 tonnes - meant that only very large craneage could be used. Detailed planning identified that a 1,200 tonne crane, the UK’s largest, could erect most of the structure with the assistance of a smaller 500 tonne crane for some lifts.

On 21 September 2015, the Sarens’ AK680 Gottwald crane arrived on site for the start of a four-day assembly process. A 100-tonne attendant crane was used to assemble the vast 83 metre main boom, which stretched the length of the site compound.

On the weekend of 26-27 September, the 1200 tonne crane successfully lifted and installed the 250 tonne central fuselage section. The lift included 25 tonnes of multiple spreader beams and other lifting tackle that had been attached prior to the possession.

Once the possession was granted, the fuselage was lifted from the carpark and slewed towards the track, to enable the super lift tray to be attached to the crane and the load jibbed out to its final position. The 168 connection bolts were installed and the possession was successfully handed back an hour ahead of schedule.

The challenging installation of the two footbridge spans was completed on 4 October. These were installed simultaneously using both the 1200 tonne crane and an additional 500 tonne crane. The two spans had to be handled very carefully to prevent any twisting of the supporting fuselage. All of the lifts were

all managed in-house by Kier, rather than contract lifts.

Following the completion of the structure, the glazing, mechanical, electrical and internal cladding out were completed through the winter.

The bridge was opened to the public on 17 February 2016 and declared a great success by the local community.

At the opening, Assembly Member David Rees said: “I am delighted that we now have a modern, accessible railway station that offers improved facilities to the people of Port Talbot.

The building reflects the industrial strength of the town through its use of steel from TATA” Whether steel making will survive in south Wales is still uncertain at the time of writing, but in any case the new Port Talbot Parkway station footbridge will remain a monument to the possibilities of steel structures for many years to come.

BRIDGES AND TUNNELS

entrance area to the north and a 23.5 metre span to the car park to the south, with a large elevated ticket office, retail unit and waiting area above the platform.

At platform level, the buildings were to be completely rebuilt to provide a new passenger waiting room and toilets as well as a new office and mess facilities for Arriva Trains. The contract to design and construct the bridge was awarded to Kier. The fabrication was carried out by Miller Fabrications in Lanarkshire.

The architectural shape of the structure was challenging. The cross sectional shape was a constantly-changing irregular hexagon, with the footbridges wider at mid-span than the ends. As a result, the intermediate members and bracings joined at differing angles and inclinations; every joint was unique. The main fuselage and footbridge structures were prefabricated into base, sides and roof sections and transported to site as 20 wide loads.

The project’s scope included a 111-space car park to the south, which fortuitously provided an ideal location for Kier’s off-site, off-line assembly of the structures and their cladding externally with Kalzip and internally with German Fundermax panels.

39

Rail Engineer • August 2016

Complex S&C arrangement from tunnel portal.

TRACK

40

141 days

at

Queen Street

O

n New Year’s Day in 1842, the citizens of Glasgow were able to walk through the newly constructed 1159-yard tunnel into Queen Street station, at their end of the Edinburgh and Glasgow Railway. The tunnel had been whitewashed and gas-lit for this event, which raised funds for those injured building the railway. The railway opened on 21 February that year, with four trains a day between the two cities taking 2½ hours.

The railway company had originally intended to approach Glasgow by a bridge over the Monklands canal and build a station just north of the present station. However, the canal company opposed this, so a tunnel under the canal with a 1 in 44 gradient was required. This was too steep for locomotives of the day so, up until 1908, trains were hauled up this incline by cable and descending trains had a special brake wagon.

This steep tunnel continues to present operational and maintenance problems, although the canal is long gone with most now buried under the M8 motorway. Yet the canal

Concrete pour from Cathedral Street.

company’s objection gave Glasgow its Queen Street station, which was closer to the city centre than originally planned.

The original station soon proved woefully inadequate for its increasing traffic and so was rebuilt between 1878 and 1880. The tunnel, whose original southern portal was just south of Cathedral Street, was shortened by 153 yards to create a new station throat and platform extensions. The wrought-iron arched roof was built at this time. As part of an East-West line under the city, the Low Level station was excavated underneath the original station and opened in 1886.

DAVID SHIRRES

Out with the 70s In the 1970s, concrete slab track, then a new innovation, was installed to reduce track maintenance in the heavily used tunnel. As this slab track is now at the end of its design life, it has been subject to much remedial work, including the use of ‘hedgehog’ sleepers with protruding reinforcement to key into the infill concrete. In 2011, Pandrol SFC baseplates were installed under the tunnels’ track to provide horizontal adjustment to compensate for the deterioration.

With station usage set to grow from its current 20 to 28 million passengers by 2030, Queen Street station has to be rebuilt. Standing in the way were some other 1970s developments, Consort House and the station’s adjacent hotel extension, both of which obscure the station frontage. When the station rebuild starts in 2017, these buildings will be demolished to reveal the arched roof and increase the station’s footprint so the new station can have increased concourse space, improved accessibility, remodelled passenger facilities and longer platforms.

Lengthening the platforms is being undertaken in two stages. The first is re-modelling the station throat, along with associated platform alterations. The second stage is the major station rebuild which includes further platform extensions. This will enable new electric trains (issue 139, May 2016) to operate in seven-car formations from December 2017 and as eightcars from December 2018.

With the need to both replace 1.8 kilometres of tunnel slab track and undertake station throat works, a lengthy closure of Scotland’s third busiest station was inevitable. So, on 20 March,

Rail Engineer • August 2016 Queen Street High Level station was closed for twenty weeks. During this time a comprehensive plan ensured passengers could get to Glasgow, albeit with extended journey times. Trains were diverted to the Low Level station or the city’s Central station, additional use was made of the line via Airdrie and Bathgate and extra local buses were provided for local stations.

The main Edinburgh to Glasgow trains were diverted over a new junction at Anniesland to the west of the city, built at a cost of £20 million specifically for this purpose (issue 136, February 2016). This involved a 20 kilometre circular diversion through the North Clyde lines to the Low Level station.

41

First concrete base poured.

This 141-day closure follows a 44-day blockade last year to install slab track in the 338-metre long Winchburgh tunnel (issue 130, August 2015).

This was the first UK use of the STA (Slab Track Austria) slab track system, which is being installed in the 918-metre long Queen Street High Level tunnel as part of this blockade. This, and the associated station works, will require around half a million man-hours work and cost £60 million, with an approximately equal split between the tunnel and station work.

It took two years to plan the complex interaction between all the work packages for which the main constraint was the need to keep one line through the tunnel operational at all times to deliver the work. Network Rail considers this to be the largest piece of engineering work on the EdinburghGlasgow railway since it was built.

Principal contractor for this work is Morgan Sindall, which was awarded an alliance contract in 2014 for the core EGIP physical works. This is a riskshare agreement - intended to create a collaborative environment.

Morgan Sindall has engaged CPR for platform extension work, Story Contracting for the removal of the existing slab and construction of the base slab, Siemens for signalling and Babcock for the trackwork which, in turn, procured the services of Rhomberg Sersa who are the licensed installers

TRACK

£60 million blockade

of the STA slab track system (manufactured by Porr AG). Rhomberg Sersa would also install the Sonneville LVT slab system for the S+C within the tunnel. Another EGIP alliance contractor, Costain, installed the station’s OLE and a Furrer+Frey conductor bar in the tunnel.

Work outside the tunnel Track renewals work undertaken by Amey Sersa north of the tunnel started as soon as the blockade possession had been taken. This involved the renewal of three kilometres of track and five point ends, and the refurbishment of four more. This restricted movements into the tunnel, so slab track work could not start in earnest until this phase was complete.

Other work north of the tunnel was the demolition for electrification clearance of Gourlay Street and Fountainwell Place bridges at the end of May, during a three-day window when train movements were not required through the tunnel.

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Rail Engineer • August 2016

TRACK

42

Grouting PORR units.

Also starting as soon as the blockade was taken was a 13-week programme to reconfigure the station throat to accommodate seven-car class 385 units. This involved 2,000 cubic metres of platform demolition and the construction of 642 metres of platform walls. 615 metres of new track was laid in the station as well as seven new switch and crossing units on timber sleepers, which were first constructed off-site to check components and methodology. A further four S&C units (slab track S+C) were replaced in the tunnel and a total of 455 metres of new drainage was installed.

Other work in the station included a new housing for the upgraded signalling, a new signal gantry and the provision of nineteen OLE structures with associated wiring. New standards were provided for lighting and the station PA system, which had previously hung from the station roof but could not remain there after electrification.

The project team took advantage of the blockage to excavate platform wells beyond the current buffer stops. As there is no space to extend platforms until the station is rebuilt, these were filled with polystyrene blocks and resurfaced for easy excavation during the station rebuild.

Other advanced works included the removal of redundant tunnel cables and, at the top of the tunnel, the provision of a cut-off drain into a sewer to minimise water flow into the tunnel.

Once the blockade started, tunnel, lighting, ventilation and communication systems were installed and a coring machine was used to prepare the slab track for its removal prior to completion of the track renewals work north of the tunnel.

Story Contracting project manager Eddie Esdale is responsible for the removal of the old slab track, constructing a concrete base layer that would eventually be used to construct the new slab track on and installing a new drainage system between the Up and Down base slabs.

To minimise vibration, the old slab track was first cut up by horizontal and transverse saw cuts and then broken up using remote hydraulic breakers. Specialist concrete cutting contractor Corecut was engaged for this work, which produced 10,000 tonnes of concrete lumps

which were removed from the tunnel on trains that each took 400 tonnes. Once the base sandstone rock had been exposed, it was found to be uneven and had to be trimmed between 50 and 300 mm to lower track level by 30 mm.

This work was completed in two seven-week phases, first the Up line then the Down line.

Eddie regarded the logistics of the blockage to be the biggest challenge with a train going through the tunnel every day for the station work and work north of the tunnel sometimes blocking access. Typically, his work required a materials removal or supply train each day, with three on-track machines and three off-track machines working in the tunnels in addition to various hand trolleys.

Eddie and his team had to mitigate the risks of working in a tunnel with such a severe gradient, for which a number of precautions were taken.

These included the use of low rail on-track plant for better traction and braking and a specially devised clamping system for hand trollies.

Breaking up the slab Unlike Winchburgh, the Queen Street work required the removal of the previous slab track.

With the unprecedented nature of this work, a trial breakout was undertaken in December to confirm the proposed methodology. This removed 20 metres of the tunnel slab track, which was then temporarily replaced with ballasted track.

Newly extended platforms 3 and 4.

Rail Engineer • August 2016

43

Supply by shaft

The Austrian system Rhomberg Sersa first trialled the STA slab track system on the Old Dalby test track in Ashfordby tunnel (issue 116, June 2014). It is Austria’s standard slab track system and is widely used in Germany having recently been used on the German VDE High Speed Rail Project.

The principal element is a 5.2-metre-long, 160mm thick concrete baseplate with eight pairs of track fastenings. These are secured on the concrete slab by self-compacting concrete (SCC) that is poured through 640mm square tapered openings in the baseplate after it has been accurately positioned. The SCC reinforcement and 80mm thick support blocks are first placed on the flat base, which is sufficiently flexible to be accurately positioned using the five jacking screws in the baseplate.

The baseplate incorporates an elastic rubber coating to absorb vibration and which also serves as a barrier between the baseplate and the SCC. In the event of derailment damage, this enables the base plate to be replaced in a matter of hours once rails are removed by breaking out the SCC.

TRACK

The concrete for the STA system base slabs was supplied through the two original tunnel construction shafts. These are around eight metres square and capped with decks on 300 mm full width cast beams.

To get concrete through these capped shafts, surveys and temporary design calculations were undertaken to determine where they could be penetrated. A 75 mm pilot hole was then drilled from which a 200 mm hole was created for the 120 mm pipe through which concrete was poured into a trailer wagon attached to a road-rail excavator and taken to the cast slab framework awaiting its concrete. This shaft hole was also used to supply water and compressed air to the tunnel.

Casting the base layer required 2,500 cubic metres of concrete. On the Up line, the first base layer was cast on 21 April and the last one on 19 May. 3,245 steel dowels, drilled 2.2 metres into the base rock, were required to anchor these slabs.

Fixing OLE brackets in tunnel.

On 3 June, Network Rail announced that the blockade had reached its halfway point and, with the Up line finished, was on schedule to re-open the line on the 8 August. By 11 July, all the STA units were in place and the main work remaining in the tunnel was Costain’s installation of the Furrer+Frey overhead line conductor bar.

The PM’s tour On 14 July, Rail Engineer was given a tour of the blockade works by the project managers from Network Rail and Morgan Sindall, Gary Murphy and Neal McKenzie. At this time, the slab track was complete, tunnel conductor bar brackets were being installed, platforms were being prepared for surfacing and most station OLE masts and brackets had been erected.

Gary also stressed the point about the logistics involved in keeping one line open and that the blockade always had to be ready to accept ballast trains through the tunnel. He advised that, while almost all heavy materials were delivered and removed by train, some were also supplied through the site

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44

Rail Engineer • August 2016

TRACK

Neal commented that the only time that work didn’t go to plan was when unknown services were found in the platforms. One item found during the excavations at the station throat was a pulley wheel from the original cable haulage system, a reminder of the tunnel’s heritage.

As with most projects, signalling work is generally the last to be completed. At the end of the blockade is a ten-day wheelsfree commissioning period. This reflects the signalling works undertaken which include the replacement of track circuits from the buffers to the north portal by Thales AzLM K axle counters.

All signals within this area were replaced with Dorman signals with LED heads used in the tunnel.

The new points in the throat have SPX In-Bearer Clamplocks, while those in the tunnel are operated by HW point machines. To accommodate new despatch arrangements for the class 385 units, new equipment is being fitted to enable platform staff to operate indicators for closed door (CD), right away (RA) and train ready to start (TRTS).

Eventual transformation

compound at Queen Street station, where lorry weight was limited due to the bridge over the Low Level line. A part-road closure had been taken on the Cathedral Street bridge over the station to supply materials, including pumped concrete and the bricks and copes for platform re-construction.

Neal mentioned that the three parts of a new signal gantry had also been delivered from this bridge. After its assembly on the station’s tracks, a 250-tonne Kirow crane had been brought through the tunnel to lift the completed gantry into place. This crane was booked months before the blockage and is an example of the detailed planning that had taken two years.

Regular passengers will be glad to see normal services from Queen Street High Level resume on 8 August, although some may wonder why the station has been closed for twenty weeks.

A huge amount of work was done during the blockade, but this may not be evident to the average commuter, especially if they don’t follow the informative @NetworkRailGQS Twitter account.

It may be some time before such passengers notice a difference. They should see the first new Class 385 electric units in August next year, which will operate a full Edinburgh to Glasgow seven-car formation service in December 2017 to provide 27 per cent more seats than the current six-car Class 170 diesel units.

Preparing tunnel floor for concrete base next to installed track.

By then, the reconstruction of Queen Street station will be well advanced. Unlike the current blockade, this should not disrupt train services as the required track and platform alterations are minimal and have been partially completed by this blockade.

By December 2018, a full eight-car service will be introduced, offering 45 per cent more seats than the present service. Journey time between Scotland’s main cities will then be reduced to 42 minutes. A few months later, the new Queen Street station will receive its final touches. By then the transformation will be evident to all.

46

Rail Engineer • August 2016

Tamping essential for good track alignment T

TRACK

GEOFF BROWN

rack tamping machines play a vital role in the maintenance of track. They are complex and expensive railway maintenance machines and can be found all across the world’s railways. Yet often little is known about them. For instance, what is their purpose and how do they work?

Firstly the reason tampers exist - railway track settles with the passage of traffic.

This would not be a problem except that track doesn’t settle evenly, for many and various reasons, resulting in an uneven track formation. Trains require good alignment of the top of the rails. If not maintained correctly, rough riding and even derailments will occur.

The faster the train travels along the track, the more important it is to maintain that good alignment.

The development of tamping Years ago, alignment of track was manually maintained and required whole teams of men using sighting board levels and small tin cans full of ½” stone. They would manually align track with bars to improve lateral position using skill, string lines and sighting boards.

Track top alignment was achieved either by using levelling boards or by measuring dips to be corrected. Men would open out affected beds, jack the track (often in between trains) and add quantities of ½” stone skilfully placed from shovels. The amount of stone required was measured out from small tin cans at the rate of one can = 1/8” of lift.

Over the years, the then British Railways progressively phased out manpower, replacing it with tamping machines. We are now at the point today where tamping machines are used almost exclusively to achieve good top and line of the track. They work extremely well and are efficient and accurate.

The tamper adopts a different technique - it consolidates ballast beneath each sleeper

creating pyramids of consolidated stone.

To do this, tamping tools are driven into the ballast, drawn together whilst vibrating at an appropriate frequency to fluidise the ballast.

During the period the tines are driven into the ground, hydraulic jacks lift and align the rails.

Early tamping machines would simply pack the track but, as technology evolved, so did the tampers. There are several different types of tamper machines; plain line track tamping machines and points and crossing tamping machines, some with 12 tools for use on tracks with conductor rails, others with 16 tools where there is no conductor rail. Then there are also 32 tools to tamp two sleepers at a time and 48 tools to tamp three sleepers at a time. All are diesel powered and can travel across the country at speeds of up to 60mph (100km/h) - this same engine is used to power the track tamping equipment.

Balfour Beatty has a seven-year contract to supply the Network Rail National Supply Chain (NSC) with on-track machines including tampers, and has been providing track alignment services in the South East, Anglia and Wessex routes for over 25 years. This section of the railway is the most densely used by the

travelling public, with people travelling or commuting in and out of London. Consequently, ensuring the track is perfectly aligned comes with great challenges and responsibility.

Managing risk and safety is pivotal in all operational activity and, to assist with this, Balfour Beatty utilises a 24-hour control centre service which logs real-time data from live sites and provides activity reports on request to Network Rail and key stakeholders.

Why tamp?

Tampers fix track problems caused by the passage of traffic. The greater the tonnage often means the larger the movement of the track and the more tamping intervention is required. During a typical maintenance shift, a tamping machine may maintain around a mile of track. These days, to maximise the benefit of the tamping machine intervention, work can be focused into very short lengths of track to correct specific issues.

Network Rail operates various systems to understand the condition of its track assets; most obvious is the high-speed track recording train. This travels the entire national network recording track quality as it goes. The output is fed down to the local track managers who monitor trends in track degradation and, from that trend analysis, develop their maintenance plan, which also includes tamping.

Rail Engineer • August 2016

47

TRACK

Balfour Beatty’s Engineering and Technology Solutions business, in fact, supports Network Rail with collecting this data through innovative track measurement equipment that is deployed across the country and feeds into the National Gauging Database. The maintenance and tamping plan results in a tamping machine arriving at the worksite to correct the recorded track errors.

Tamping explained All modern high-performance tamping machines have a measurement system to enable them to understand where faults exist on the track. This measurement system requires three trolleys - one at the front of the machine, one in the centre (known as the measuring trolley) and one to the rear. A straight line is created between these three trolleys in the form of a beam of light or a tension wire. At the measuring trolley, any misalignment - horizontal or vertical - is recorded as an electrical signal.

These signals are fed into the tamper’s control system that directs the working units to adjust the track.

There are a number of ways in which a tamper works. Simple smoothing is where the tamper surveys and adjusts the track using errors measured only between the front and rear trolleys. The tamping machine can only see the errors between those two trolleys, therefore the machine can only improve track over that short distance. This can leave long-wavelength faults and is generally not used in the UK anymore.

The second method is more commonly used, and involves the tamper measuring the entire track length between ‘Point A’ and ‘Point B’, a distance which may be up to a mile in length.

The machine's guidance computer notes all the track errors and subsequently computes a track design using an algorithm to provide the best possible horizontal and vertical alignment through the points.

If, during the measurement process, there is a requirement not to move the track, for instance where a point passes close through a bridge, tunnel or station platform, the operator puts fixed points into the programme and that tells the computer to hold the track position at those points.

Once the computer has developed its programme the operator and inspector check it and, once satisfied, commit the program to the system, position the machine correctly and commence tamping. The benefit of this method of working is it has the effect of extending the length of the tamping machines guidance system to the full length of the site, ensuring there are no long-wavelength track faults.

The third method of working is usually known as the geometry method. This is most often used in track renewal on the West Coast main line, where the as-built design is available, especially around areas of switches and crossings. A design for the track to be tamped is developed off-site by technical staff, and is input to the tamper’s computer to allow it to understand what the finished track should look like. The machine makes a measurement run of the site and the output is the difference between the design and the track as it is before correction. A correction file is generated which informs the machine where and how much track to deploy.

New software has been developed that allows the tamping machine to repair discreet errors on a single rail. As described earlier, tamping

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Rail Engineer • August 2016 Plasser & Theurer USP 5000c.

TRACK

machines use measuring trollies to understand where the track is and what errors may be in that track. The new piece of software allows the machine to correct discreet errors on single rails without the need to maintain hundreds of metres of track. This is particularly useful on high-speed railways, in particular High Speed 1.

Using this innovation, tamping machines can rectify 20-30 metre faults without disturbing the other rail.

Youthful and versatile Within its fleet, Balfour Beatty owns 17 tampers, which include eight Compact Plasser and Theurer machines, six Matisa Tampers and two Plasser Unimats. Of these tampers, 16 are under contract to Network Rail. The newest machines, the Matisas, were built in 2010 with an investment of approximately £20 million for the six machines. The asset life of a tamper machine is 15-20 years and. with the exception of the Network Rail High Output fleet, Balfour Beatty has the most modern fleet of tampers in the UK.

All machines are fitted with the necessary equipment to work on the main line, just like the locomotives and multiple units that run on Network Rail tracks. To that end, they are fitted with Automatic Warning System (AWS), GSM-R, a Train Protection Warning System (TPWS) and On-Train Monitoring Recorders (OTMR).

The whole fleet is also fitted with Track Circuit Actuators (TCA), to enable detection on track circuits when travelling on the network.

Balfour Beatty owns the only two Matisa B66UCs in the UK. These are continuous-action universal tamping machines, which can tamp plain line as well as switches and crossings.

When in plain-line mode, these machines can operate cyclically or continuously.

Tampers have traditionally operated cyclically, that is why they stop over the sleeper/s to be tamped, complete the process and move onto the next sleeper. This requires the machine to stop and accelerate at every sleeper (or pair or three sleepers depending upon the type of tamper). When in continuous action mode, the body of the machine moves ahead continuously but the working units stop start and accelerate forward, saving fuel and improving the operator experience.

Tamping through switches and crossings is a slow process as the track geometry is constantly changing as the machine moves through the switch. Typically, it takes around 40 minutes to complete a single switch (lead), depending upon the cabling and condition.

Balfour Beatty has a significant footprint in the South, with depots at Woking, Colchester and Hither Green and further access to depots in Ashford, Romford, Eastleigh, Three Bridges and a Midlands depot in Sandiacre, Derbyshire. All of the fleet has been adapted to work within third rail environments, so Balfour Beatty machines can be easily deployed to operate across the network.

Track renewal and maintenance play a vital role in ensuring that the rail network operates safely and reliably. The function of tampers in maintaining track alignment is equally as important. Balfour Beatty has deep route knowledge, expertise and capability in maintaining the nation’s railways and is investing in research and development to further improve the infrastructure and help reduce the cost of track maintenance.

Geoff Brown is engineering development manager, Balfour Beatty.

The experts on track Balfour Beatty provides innovative, flexible plant solutions for all track improvement works.

Our trusted team offers a complete track geometry service, ensuring our customers’ most exacting requirements are met safely.

As a leader in the operation and maintenance of all on-track machines, we understand the importance of an efficient and modern railway.

For more information, contact us: rail@balfourbeatty.com www.balfourbeatty.com/rail

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Rail Engineer • August 2016

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GRAHAME TAYLOR

H

Landfill journeys

ere at Rail Engineer, we’ve made occasional mention of alternative track support materials. But, time and again, the industry reverts back to traditional materials such as timber and concrete. They do the job. There is an established supply chain. They are a safe option and there’s plenty of plant and equipment designed to cope with them. They have problems too - timber quality and availability is declining and price is increasing, creosote will be banned in 2018, mid-life extensions are time consuming and expensive, and concrete is heavy and too stiff to be mixed with timber.

But time and technology moves on, and this often produces alternative ways of doing things - without causing a quantum shift in equipment, infrastructure or work practices. Ideally, delivering better value too.

Recycled bottles At the recent Rail Live event at Long Marston, there was a recycled plastic composite sleeper being displayed by Sicut Enterprises. Proven in the US over the past 20 years, this material now stands a real chance of changing the way that track is assembled in Europe.

What does it look like? Well, like a sleeper, except that it is black. The initial impression is that it is very hard and durable, nothing like as heavy as concrete, and even without treatment will not rot or be gradually eaten by all the creatures that have timber in their sights. It can be handled and installed in exactly the same way as timber.

Looking good so far.

Sicut’s composite sleeper is manufactured from a blend of recycled plastics. Within that enigmatic black shape there are countless plastic bottles, as well as waste materials from the automotive and other industrial sectors - in fact, materials which stood a very good chance of ending up in landfill.

So, one could argue that track made using Sicut’s sleepers is in effect a most acceptable and very long landfill site. The fill - the sleepers - are doing something really useful, instead of just becoming an environmental menace.

At the end of life - however, if ever that occurs - old Sicut composite sleepers can simply be returned and put back into the ‘cooking pot’ to make more sleepers, or one of Sicut’s other structural composite products.

Also, in addition to the obvious environmental benefits, detailed cost modelling and track experience has shown that the durability and long life of Sicut’s composite sleepers should deliver very significant whole life cost savings for customers.

Development So, has this new product come out of the blue - or black?

Of course not. And has it just been developed for main line railways? Again, of course not. While sleepers made using Sicut’s technology have been proven in passenger lines at 200 km/h, as well as Class 1 freight lines at up to 39 tonne axle loads, they have also been successfully used on many other types of railway - including in the rather un-glamorous world of mining.

For most products, the rail industry is one that takes very few prisoners. The conditions are harsh, or even extreme, and the commercial pressures are intense.

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Rail Engineer • August 2016 They’re also being used in subways - normally an environment where fire precautions loom large. In Milan, these sleepers have been embedded in concrete and have been in service since 2006 and Long Island Railroad has had them installed in the New York Subway since 2013. One of their additional benefits in subways, and indeed on bridges, is that of vibration attenuation.

So far, mention has only been made of ‘sleepers’. But this generic term covers a multitude of shapes and sizes.

Switch and crossing bearers for example, usually sourced from imported tropical hardwoods, are also made from Sicut’s composite and have been successfully used around the world. They are made consistently in lengths that would challenge many hardwood suppliers. They are not subject to the vagaries of natural variations. There are no splits, shakes or knotholes. No twists, bends or variations in dimensions - unless, of course, these are specified.

An engineered material is, after all, more precise than a natural one. They can also be stored outside before installation without any risk of taking on moisture or degradation.

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52

Lateral stability

Railway components have to perform. And Sicut’s plastic sleepers do perform. After over 20 years and billions of gross tonnes of traffic, they have not split, rotted or degraded - performance remaining unchanged since the day of installation.

Sicut’s composites and manufacturing processes have been developed over the past 30 years, derived originally from research carried out and led by Professor Thomas Nosker and his AMIPP department at Rutgers, the State University of New Jersey, USA. This globally renowned centre is dedicated to exploring immiscible polymers and the novel structures and materials that can be obtained by processing them. This is a technical way of saying that they design structural materials from mixed plastic rubbish. Or, as Sicut likes to describe it, they “Turn today’s waste into tomorrow's infrastructure”. Alongside Sicut, Rutgers remains very much involved in the technology today.

The range of Sicut’s structural components is wide, from railway sleepers to bridge structures, marine pilings, I-beams, heavy-duty boards and ground mats. Indeed, complete road and rail bridges have been made from this composite technology.

So the sleeper on show at Rail Live wasn’t just a single product line, but part of a wide portfolio of proven products, all derived from low quality plastic waste.

Worldwide Having seen very few composite sleepers in the UK, the question had to be asked: “Who uses them?” And the answer is quite a few countries - sixteen to date. There’s the USA for a start, Canada, Russia, Mexico, Australia, New Zealand, Brazil, Chile and Wales. Yes, Wales - on the Ffestiniog Railway. France, Germany, Belgium, Sweden have all granted Sicut approvals for initial track installations and London Underground, having completed its track trials in 2015, has granted full APR (approved product register) approval for Sicut’s plastic sleepers.

There is one intriguing detail that needs an explanation.

They may be black, they may be made to the same dimensions as timber, but their sides and base are covered with interesting conical indentations. These, as business development director Anil Aggarwal explained, have been carefully designed and tested to provide the necessary lateral and vertical track stability.

The sleepers are very hard, and the ballast won’t dent the sides or base to anchor the sleeper in place. The indentations ensure that the ballast locks into the sleepers and secures the track immediately after installation. Indeed, the measured lateral stability of Sicut’s composite sleepers is similar to that of concrete, despite the composite version being less than one third of the weight.

New UK facility Despite a quiet start, there are developments in the UK major developments in fact - with the opening of Sicut’s first composite sleeper production line in Castleford, near Leeds, to supply the UK and European markets, whether that is for mainline, industrial or underground customers. Ultimately, the facility plans to use up to 25,000 tonnes of locally sourced waste material, much diverted from what was an inevitable path towards landfill.

The UK plastics recycling industry has taken quite a hit recently. Plunging oil prices have meant that the costs of new plastics have also gone down, which leads to a drop in demand for alternatives made out of recycled material.

To a very large extent, the opening of the new composite sleeper facility can be seen as a lifeline for this embattled industry. Indeed, the Government’s Waste Recycling Action programme (WRAP) seems to think so - it is a stakeholder.

This level of investment in the UK is an indication of the confidence that composite sleepers really are a viable alternative to concrete and timber track support in Europe.

Before long, it could be that your train will be traveling over its very own landfill site, a landfill site that everyone will be quite happy to have “in their back yard”.

Rail Engineer • August 2016

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54

Rail Engineer • August 2016

TRACK

MILLING brings a new lease of life to DAMAGED TRACK Strabag’s SF02 on track.

The cutter head.

T

he technology of mobile rail milling has developed over the last 20 years to become a mature and proven method of rail head treatment.

Across central Europe, the process has been accepted as part of a rail engineer’s ‘toolbox’ and has been used effectively to improve rail head management.

During that 20-year journey, Rail Engineer has looked at the technology on several occasions, most recently in issue 84 (October 2011).

Three years ago, the DB Netz fleet in Germany consisted of nine rail millers, a similar number to its rail grinders. However, as the German infrastructure owner has now spent several years maintaining its network regularly, rail head management has stabilised, meaning the demand for rail milling is actually falling.

This all benefits the UK’s railway, as one of Strabag’s SF02 road-rail milling units, previously used in the UK and the subject of Rail Engineer’s 2011 article, has been freed up to work on Network Rail’s infrastructure.

Approval Bringing the SF02 to the UK has been made possible by close collaboration between Strabag and Network Rail’s profile treatment team, which is also responsible for the rail grinding fleet of trains and support services.

In fact, the Network Rail team sees the introduction of milling as being complementary to the rail grinding service already on offer. Milling enables more metal to be removed, which helps restore the rail profile. This will then release the fleet of grinders to carry out regular preventative maintenance around the network.

The EAC (Engineering Acceptance Certificate) approval process was supported by Aegis Engineering Systems, whilst ongoing operational support is from TES 2000 and Bakerail Services. There is a close working relationship with Network Rail’s route teams to identify sites that need to be treated, which is then followed up with inspection to confirm suitability.

Having obtained engineering and product acceptance at the beginning of 2016, the road-rail milling machine has completed 23 shifts across the UK, from Scotland to Wales. This geographical flexibility stems from its ability to move between sites in road mode before being quickly set to work on track, without requiring a train crew or routing to move it around the rail network. So far, 16,756 metres of milling (single pass) has been carried out while improving 7,844 metres of track, factoring in multiple passes.

The rail milling process At the heart of the process is the milling cutter head. Fitted with paired rows of tungsten carbide cutter tips, it rotates at high speed, generating thumbnail-sized pieces of swarf which are contained within an enclosure and recovered for recycling. This creates a safe working environment for those working around and alongside the machine. The rail profile is generated by the shape of the cutter head, not the individual cutter tips, resulting in a consistent finish to close tolerances.

The cutting process leaves small facets on the rail head which, if not treated, would result in a lowpitched rumble from the wheels of rail vehicles passing over the track.

Consequently, a grinding wheel, set at 10 degrees across the rail head, removes the facets on the rail - in the wheel contact patch area - resulting

Rail Engineer • August 2016

The truck The machine being used in the UK was built in 2010 by Linsinger of Austria. The tractor unit is based on a MAN vehicle while the trailer is purpose-built and contains all the control systems together with a selfcontained power source for the milling and grinding operations.

TRACK

in a final surface roughness of around 3µm. Once again, the grinding wheel is mounted within an enclosure, allowing any dust to be recovered and containing the small stream of sparks generated by this light grinding, significantly reducing any potential fire risk.

The guidance system of the milling unit is such that any existing rail head imperfections, such as longitudinal or transverse ‘waves’, whether long undulations or short corrugations, are removed completely.

As a process, rail milling is very clean and, with an operating noise level of 82dB, provides a good working environment for operatives and doesn’t annoy lineside neighbours.

Effective recovery of milling swarf for re-cycling is a significant environmental ‘tick in the box’, whilst the collection of grinding dust prevents both health issues and any effects on signalling and other lineside systems.

55

Not being rail bound, the unit has the flexibility to move around the country on the road network.

However, it does require a suitable on-tracking location to enable it to transfer from road to rail and back again.

The operation is entirely selfsupporting with a crew that both operates and maintains the vehicle, backed-up by a well-equipped mobile workshop in a separate truck that travels with the machine.

Complementary process Rail milling is not a replacement for rail grinding. This is a common miss-conception. Rather, it is complementary both to grinding

and to other initiatives that aim to improve rail life and reduce the effects of rolling contact fatigue (RCF) such as improved grades of steels, friction modifiers and preventative profiles.

By removing between two and four millimetres of material, milling can recover rail damaged through cracking or plastic flow, restoring it to ‘as new’ condition having removed surface defects and re-set the rail profile, so extending its life. In some cases, by the effective application of milling, and with interim control through such measures as preventative grinding and friction management, the life of a section of track can be more than doubled.

The Milling head is in the enclosure to the right, the grinding wheel to the left. Note the small amount of sparks which are completely contained within the unit.

Good retention of milling swarf and grinding sparks means that the SF02 can continue working safely past other work sites.

Rail Engineer • August 2016

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56

Warrington - severely damaged rail (inset) was reworked to restore the profile and bring the surface roughness down to below 5µm.

Working In the tunnel at Heathrow.

Recent successes Since the SF02 was introduced onto the network, a number of problematic areas have already been tackled.

The machine undertook its final trials for product acceptance on the Timperley and Garston lines near Warrington, a heavily used freight route for coal, and as a result of the good work carried out has since returned. One of the earliest identified applications was the treatment of heavily damaged low rail with plastic flow and head defects. There was concern that the condition of the track could damage wheelsets and make train passage noisy and uncomfortable. Whilst not unsafe, the rail still required up to six passes in places to recover the profile. Since its initial visit, the machine has recently returned to treat further sections and avert the significantly costlier process of re-railing.

Once its EAC had been issued, the first site to be visited by Strabag’s SF02 was at Barassie in South Ayrshire.

This was a classic situation with both rail defects and poor profile. Despite initial nerves due to the newness of the process, the machine performed faultlessly and the route team was more than satisfied with the final result.

A length of track at Kingsbury had suffered rail head damage from a particularly bad wheelflat, and this initiated squat defects over some six miles of track. Initial treatment by single-pass grinding did not remove the defects due to their depth. Milling was the only option other than re-railing.

The SF02 was able to remove up to 0.9mm in one pass, an average being 0.6mm, and leave a finish roughness of between 2 and 5µm, which successfully tackled the problem.

Rail milling is a good process to use in tunnels as the milling process is clean and the reduced amount of grinding sparks minimises the risk of fires. This ability was put to good use at Heathrow on infrastructure managed by Network Rail’s Reading delivery unit. While the rail head profile has not suffered the level of deformation seen at Warrington, rolling contact fatigue up to 1.5mm deep had been measured using eddycurrent measuring equipment.

Previous use of a rail grinder to remove the defects had not proved entirely successful as the machines were unable to get to the area frequently enough and, with the amount of metal to be removed, the RGH-20C switch and crossing grinders could not meet the requirement. The rail miller proved to be ideal as it removed the depth required in two passes and worked within the tunnel environment without issue.

Further shifts are now planned both at Heathrow and around the country as Strabag’s SF02 road-rail miller tackles some of the network’s most problematic stretches of track.

STRABAG Rail GmbH is an international railway construction company and part of the STRABAG SE Group. With more than 90 years of experience, we provide valuable momentum in the planning of railway construction projects and set high standards of quality for the execution of construction work. Our portfolio comprises one of the largest and most modern fleets of rail milling machines, including two units of the Road-Rail Milling Machine SF02 W-FS Truck and two units of the Rail-Borne Milling Machine SF03 W-FFS. With our state-of-the-art equipment, backed by the expertise and dedication of a highly qualified team, we are capable of executing all types of rail treatment projects in the required time and quality. Our rail milling technology offers the following applications and advantages: reduced maintenance of rails and rolling stock; extended rail life cycle; milling and grinding in one pass; treatment of all rail profiles; removal of rail defects; restoration of transverse profile; perfect finish with no facets even on tight curve radius; gauge widening; high productivity and constant quality; lower spark and dust emissions for reduced fire hazard in tunnel areas; lower noise emissions; recycling of all wastes and residues.

STRABAG Rail GmbH, Business Unit Rail Treatment/Products, Bessemerstr. 42b, 12103 Berlin/Germany, www.strabag-rail.com Paul Baker for STRABAG Rail, Bakerail Services Ltd, 4 Green Lane, Hail Weston, St. Neots, Cambridgeshire, PE19 5 JZ, Tel. + 44 1480 471349, www.bakerailservices.co.uk

58

Rail Engineer • August 2016

High-output track renewal, German-style

D

TRACK

uring the spring of 2016, the railway line from Hamburg to Cuxhaven in northern Germany was renewed in stages. This line, which first opened on 1 April 1881, was exactly 135 years old when the renovation work started. In former times, it was of great importance for emigrants who left the train in Cuxhaven to board ships bound for North America. Nowadays, most of the travellers are commuters although there are also some tourists travelling to and from the North Sea. Cuxhaven is an important centre for the automotive logistics industry, so freight is also a key of this line.

Due to both the commuter and freight traffic, it was not possible to reconstruct the track under a full possession. The best that could be done was to close one track and run all of the traffic on the other. So all of the work would be carried out ‘adjacent line open’.

Phased renewal

View along the platform edge at Dollern – note there is plenty of room for the guide rollers of the RU 800 S to move the old rail to the side and replace it with the new rail.

Work on the Cuxhaven-bound line was due to start around Easter 2016.

The Austrian firm Swietelsky was contracted to carry it out and the work was managed from the company’s Munich office. The company has its own fleet of track-renewals machinery, along with an experienced workforce, and is also a member of Eurailpool, a joint venture between Swietelsky and GSG Knape. The Plasser & Theurer PM 1000 URM formation rehabilitation train and MFS conveyor and hopper wagons would be sourced through Eurailpool.

The work was divided up into several phases. After preparatory work, much of which could be carried out between trains on the live railway, the northbound track was closed under possession so that control and signalling equipment could be dismantled and for minor track work.

Following this, on those sections of the track where the whole formation needed replacement, the PM 1000 URM would raise the track, undercut the entire trackbed, clean and screen the ballast layers, replace the formation protection layer and ballast, installing a geotextile if necessary, and reinstate the existing track to be used by further construction trains.

Next, an RU 800 S would be used on the whole length of the line to remove the old track, clean the ballast where the PM 1000 URM had not already done so, and then lay new track (rail and sleepers) on top of it.

Finally, the correct track geometry would be restored using a 09-4X dynamic tamper along with an EM-Sat 120 track survey car and

a BDS 2000 ballast management system. Rails would be welded up and stressed and signalling, level crossings and other control systems reinstated.

Confined spaces To maintain efficiency, it is important that high-output trains can continue to operate alongside station platforms, over bridges and past obstacles without being seriously affected by the reduced clearances.

The PM1000 URM and RU 800 S are both able to do just that by adjusting the working width of excavating chains and plate compactors. The RU 800 S, in particular, has independently controllable shoulder ploughs to enable it to work close to station platforms. This ability was tested at Dollern station, which has platforms only 76cm high and is on a curve.

Recycling ballast Ballast is heavy, and is therefore expensive to transport any distance.

To keep the use of new ballast to a minimum, the Plasser & Theurer PM 1000 URM was used to both clean and recycle ballast.

Depending on the quality of the existing track bed, up to 100 per cent of the ballast could be reused. It was also often not necessary to use geotextiles because, after compaction, the 30-centimetre-thick formation protective layer alone met the loadbearing specification.

Any spoil that was not able to be recycled was to be taken away by material conveyor and hopper wagons (MFS) and deposited temporarily beside the line in Horneburg.

With three excavating chains, the PM 1000 URM is both quick and efficient in excavating existing ballast to any required width and depth.

Excavated material is first moved to the ballast recycling, screening and washing wagon. Any resultant spoil for disposal is conveyed on belts to the construction train of MFS units coupled on to the front.

Rail Engineer • August 2016

59

ACHIM UHLENHUT

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Fresh material, both for the formation protective layer and to top up the ballast, is transported to site using a second construction train, this one consisting of transport wagons with containers rather than MFS units.

From this train, new ballast is fed to the rear of the 52-axle, ten-unit PM 1000 URM. Both construction trains travel independently to and from disposal and loading sites along the line. To shorten the distances, a storage area for new material was established at Dollern level crossing, which was under possession anyway. Here, a wheeled loader filled the containers with ballast.

On arrival back at the PM 1000 URM, containers were transported along the length of the construction train using two gantry units running on the transport wagons. The outer gantry

continually fetched two containers whilst the second gantry unit, running closer to the machine, tipped one container-load at a time into its bunker.

This relay system, with containers being handed over partway along the train, shortened the travelling distance for both gantry units, their paths crossing only at the handover point, speeding-up operations.

Once the formation protective layer and ballast had been laid, and the track returned to position, an integrated tamping unit, with lifting and lining facilities, concluded this first phase of operation. The track was now usable by construction trains.

Overall, the PM 1000 URM was able to achieve a considerable work output.

Over the Easter weekend, in around 50 hours of continuous operation, it completed a section of almost 5,000 metres at Dollern.

Replacing rails and sleepers The second stage of the process was to remove the old, temporarily relaid, track and replace it with new rails and sleepers.

New rails had already been laid along the edge of the existing sleepers.

An RU 800 S from Plasser & Theurer carried out the track replacement in a single operation. Using an array of clamps and rollers, the old rail was lifted from the sleepers and guided out to the edge of the trackbed. Simultaneously, the new rails, previously laid alongside the old sleepers, were picked up and guided inwards. Although this process requires the rails, both old and new, to be flexed both upwards and sideways, this takes place over a 45-metre length so no permanent distortion occurs.

The BDS 2000 removing excess ballast.

Whilst the new sleepers are laid on the ballast formation, rail guiding clamps replace old rail profiles with new ones (below).

Rail Engineer • August 2016

TRACK

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(Above left) Whilst the machines were at work, the adjacent line remained open for both passenger traffic and freight.

(Above right) RU 800 S – the new (lower) rail is guided in from the edge of the track while the old rail is flexed up and to the outside.

Simultaneously, the old sleepers were lifted automatically by a conveyor and taken up into the machine, to be replaced by new sleepers brought in from the attached construction train by gantries, 30 sleepers at a time. The gantries then returned the old sleepers to the space on the train vacated by the new ones.

Top ballast, excavated after the old sleepers were removed and stored temporarily in a hopper in the machine, was replaced and topped up where necessary by new ballast supplied continuously from MFS units coupled to the other end of the machine.

Final alignment and tamping

After tamping, the new track is measured by the EM-Sat 120 survey car while a passenger service runs on the other track.

Once the ballast had been cleaned and the sleepers and rails had been replaced, the track had to be brought back to its nominal geometry. A 094X dynamic high-speed tamper with four-sleeper tamping and dynamic track stabiliser was used to achieve this. Being able to tamp four sleepers at a time, and using the continuous working method described in Geoff Brown’s article elsewhere in this issue, allowed the track to be aligned at a comparatively high speed.

Another construction train of ballast wagons followed behind, using the BDS 2000 ballast management system to ensure ballast only went where it was needed and wasn’t wasted in the cess. Shoulder ploughs and a central plough, plus sweeper units in the rear section, removed superfluous ballast after the tamping operation and re-distributed it or temporarily stored it in a bunker. An MFS wagon was added to the BDS 2000 to increase capacity.

Satellite measurement An EM-Sat 120 track survey car was used, between the high-speed tamper and the BDS 2000, to record track geometry. This electronic surveying unit records the lateral, longitudinal and vertical geometry of the track.

To do this, a small self-propelled trolley moves forward and then pauses. The main machine then moves towards it and, using laser sensors across the space between the two vehicles, the level and alignment of the track can be determined. The results are recorded on eight-channel recorders, and all measured values are stored digitally.

MFS advantages The amount of materials used in the project necessitated the use of numerous material conveyor and hopper wagons. Both when supplying material and removing spoil, their ability to convey the load from one end of the train to the other was crucial. Using the conveyors, spoil could be deposited directly at a disposal site next to the track for subsequent removal. On return to the construction site, the conveyors could carry fresh material directly to the hoppers in the machine.

If an MFS train was withdrawn for emptying or loading, several MFS wagons remained attached to the construction machine in order to avoid any stoppages. These dedicated wagons were then filled back up once fresh supplies had been brought to site, again using the on-board conveyor system.

Facts and figures Working on one track at a time, the machinery used at this worksite, some of which was unique, moved a total of 10,000 tonnes of new ballast. 11,800 tonnes of spoil was removed, and a far greater amount of ballast cleaned and returned.

The formation protective layer required 3,500 tonnes of new material.

For the track itself, 10,800 new concrete sleepers and 13,120 metres of S54 rail were installed and a similar quantity removed for recycling.

Using these construction methods, it was possible to work without interruption even through the platforms of Dollern station and over the few culverts under the line. The whole project took 27 working days and, after a gap of several weeks, another three nights for the final re-tamping.

Rail Engineer • August 2016

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Rail Engineer • August 2016 GRAHAME GRAHAME TAYLOR TAYLOR

High ideas

O

LE is a rather specialist field of railway engineering. Not many people see it happening and, if they do, it’s so spread out that making sense of what’s going on is a little difficult. OLE – overhead line equipment – is the wires and a lot else that makes up the knitting that is overhead electrification. Even from track level, the components appear strangely delicate. That’s really because, in normal circumstances, it’s never possible to get right up close without being blown away in a flash of 25kV. But at Rail Live this year, it was possible to get right up close to all that makes up the OLE - and delicate it is not! This is hardly surprising as it is, after all, railway engineering which, almost by definition, is always heavy.

Troublesome trains Up until recently, most of this heavy kit has been offered up in the air using trains, and the fact that trains are used is a hint that something substantial is being manipulated.

Trains, though, have their disadvantages. They are, after all, trains. Heavy in their own right, confined to rails – although this is blindingly obvious - dependant on stabling, route capacity and staffing just to make the thing go. They also have to arrive the right way round and marshalled in the right order – something that is often overlooked.

Does it have to be this way? Well, no. As always there are people around who can think of other, perhaps better, ways of doing things. The people who succeed in bringing out a better solution, though, tend to be those who know what they are doing. Those with years of hands-on experience. Those who have seen what can and can’t be done. What is effective and what is useless. What is safe and what is dangerous.

No quiet retirement One such guy is Les Blake (pictured left) who, by any measure, is of mature years and could have retired several years ago. But he chose not to because he loves OLE and loves rising to a challenge and making a difference.

Rail Engineer • August 2016 With such a long career, it is inevitable that he cut his teeth on many of the iconic electrification schemes. The WCML for example – and that’s the one before the postprivatisation adventure.

Shift after shift, possession after possession, Les has seen it all – warts and all.

Where is this leading? After all, after so many projects it would be tempting to opt for a quiet retirement.

But there was unfinished business. With possessions getting shorter, sidings disappearing, logistics moving away from direct control, there had to be another way of doing things. A way that didn’t involve the strictures of using trains.

Ideas

Designed from scratch

Employed now by Keltbray, Les had established himself as someone who knew what he was talking about. And, because of that, a request to call together a group of people to discuss a road-rail wiring consist concept was seen as an opportunity.

So, towards the end of May in 2013, in the Rugby depot, the concept was put forward.

Instead of using a train, how would it be if the whole operation was achieved using a main vehicle with supporting crews on follow-up vehicles.

What would this arrangement address?

Possession starts and wrap-ups. These have always been when time just slips by. Calling forward a train into position – again a time consuming process.

Limited possession times – can they be used for anything really productive?

The ideas began to crystallise. The advantages looked attractive – to the extent that 2,000-metre midweek wire runs could be on the cards. This was a seismic shift in productivity.

Where was this road-railer? It didn’t exist. It would have to be designed from scratch. All the equipment normally carried on a train would have to be condensed into the limited envelope of a street legal road vehicle.

That was quite a challenge as road-railers aren’t trains.

They’re nothing like as heavy. There’s the issue of how to ensure that wiring tensions wouldn’t just stop the vehicle in its tracks. After all it would be paying out wire at 20kN.

In a typical chicken and egg design process, it was necessary to work up what kit had to be accommodated and then sort out the chassis and the road rail equipment.

Discussions were held with SRS – well established in the field of road-rail engineering – to discover whether the vehicle would pull the wire or whether the wire would pull the vehicle. The feeling was that it would be best to go for traction on both front and rear sets of road rail gear. In the end, this was a decision that was vindicated during trials.

The UK rail loading gauge may be a limitation, but the Construction and Use regulations for road vehicles cause just as many restraints. Axle loading on a rail vehicle can be comparatively high, those for road vehicles are strictly limited. Whilst there are dispensations, the whole point of the concept was that it should be flexible and not require special movement orders or police escorts!

So, within the width, length and height of a UK street legal vehicle, Les and the team had to shoehorn winding gear capable of handling conventional wiring drums, a bull

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Rail Engineer • August 2016 wheel – in effect a large capstan that is the intermediary between a free running wiring drum and the tensioned wiring – and with everything mounted on a scissors lift arrangement. It all had to work on 150mm cant and on gradients of 1 in 25. At the back of the vehicle there needed to be the control cabin with all the control electronics/electrics.

And then there’s the money This vehicle is not the end of it all of course, there are vehicles that service the operation and those that carry the support crews who join everything up as the wiring is paid out.

Concept is one thing, production is another.

Keltbray Aspire, which is part of Keltbray Group and provides electrification services on the rail infrastructure, has invested nearly £6 million in new rail electrification plant over the last two years. Within this investment is a new and unique, multi-million pound overhead line electrification wiring unit that will provide increased safety, efficiencies and productivity to the UK’s national electrification programme.

Les’s road/rail concept is now that wiring unit and it is the only one of its kind in the UK. As he intended, it really can run out contact and catenary wires at full tension which means it halves the time it takes to install conductors for rail electrification using traditional methods.

The 32-tonne road rail chassis for the new Les Blake machine was built in Sweden by SRS Sjölanders AB while the wiring unit was developed by German-based company ZECK before being shipped to the UK.

To mark the successful commissioning of the vehicle, Keltbray named it the LB54 – LB = Les Blake; 54 = number of years of railway service.

“Traditionally, it requires three six-hour shifts to fully install and register the conductors on a tension length. The new wiring unit now allows a complete installation and full register in one six-hour working shift. Needless to say, this saves manpower and equipment but, more importantly, it enables us to reduce possession time and minimise track closures to the benefit of rail companies and passengers.

Everybody wins!” explained Director of Keltbray Aspire, Martin Brown.

The new Les Blake machine is Network Rail approved and has been working to support installation of overhead line electrification for AmeyInabensa on Great Western, and will soon be relocated to Maidenhead for work on Crossrail.

What this whole exercise shows is that if you know what you’re doing and have a really practical idea, then there’s a good chance that someone with a chequebook will make sure it all happens.

Keltbray Aspire; part of Keltbray Group, is a leading provider of overhead line electrification design and build; from consultancy to delivery across the UK. Our team has extensive experience in all aspects of railway electrification. Our expertise enables us to maximise rail availability while minimising disruption.

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Rail Engineer • August 2016

London Bridge Station Another Milestone

CLIVE KESSELL

T

he massive job to totally rebuild London Bridge station reaches a major stage over the forthcoming August bank holiday weekend. The work so far has progressed from south to north, starting with the terminating platforms, these being reduced from nine to six in total, with the new Platforms 10 to 15 being brought into service on a staged basis.

Part of this work involved taking down the large overall roof that covered this area (the main elements of which are now stored at the Vale of Rheidol Railway in Wales where it may be rebuilt at a later date) and replacing it with conventional platform canopies, plus demolition of the old terminus concourse and opening up the area towards the Shard and the bus station.

All this has been relatively straightforward, but now comes the Big One. A lot will change over the forthcoming August Bank Holiday weekend, and Andrew Hutton, the London Bridge development manager who has been in post since 2008 and intends to see the project through to completion, took the opportunity to show Rail Engineer around the site and explain what will happen.

Operational constraints The through lines from London Bridge to Cannon Street and Charing Cross have long been a problem. The notorious Borough Market Junction, just to the north of the station, has been a significant constriction for decades, there being only two lines available for Charing Cross services over the Borough viaduct.

With the coming of Thameslink services through London Bridge and onwards to Blackfriars and Kings Cross St Pancras, the situation was made much worse.

Many trains had to cross flat junctions to get into and out of the station, making day-to-day operations one of the most challenging in the country.

Additional capacity both through and to the north of the station, plus a remodelling of the lines

south of London Bridge (including a grade separated junction to get the Thameslink trains into the middle platforms), was seen as essential to solve the problem. The work, when completed, will allow Charing Cross, Thameslink and Cannon Street services to have an unimpeded path through the station, thus enabling a greater throughput of trains, especially at peak hours.

Rebuilding the platforms for these routes has been a vital part of the project.

The new station layout The through higher level lines originally had six platforms built on brick arches. The current work will create nine new platforms on a footprint that uses some of the area previously taken up by the terminating platforms. To achieve this, the arches through the central section of the station have had to be demolished and the work involved has meant closing a significant part of the station and restricting the number of train movements.

Since mid-2014, trains to and from Charing Cross have not stopped at London Bridge and the Thameslink services have been diverted to another route. This has enabled old Platforms 4, 5 and 6 to be demolished, with a minimum of two tracks being provided in different positions as work has progressed so as to retain a route into Charing Cross.

Between then and now, huge columns, cross heads and filler deck bridge spans have been built, extending across to where Platforms 7 and 8 were on the terminus side of the station, upon which the new platforms are being constructed.

Rail Engineer • August 2016

During this period Cannon Street trains have continued to stop at the station using old Platforms 1, 2 and 3.

In addition to this platform work, and in recognition of the ever-growing number of people using the station with the associated need to improve passenger flows and minimise congestion, a new street level concourse is being constructed underneath both the terminus and higher level through lines. This will provide easy interchange between Southern, South Eastern and Thameslink services.

This concourse, when complete, will stretch from Tooley Street in the north to St Thomas Street in the south, and will be the biggest passenger circulating area in the country. The station building facia to both streets is being modernised in keeping with the ambience of the surrounding area.

Interchange and access Part of the design challenge has been the provision of a walking route between the two streets for people not intending to travel by train, hence the concept of ‘paid’ and ‘unpaid’ areas. The ‘unpaid’ will be a corridor to provide the cross-station route with the ‘paid’ area being accessed by rows of ticket barriers leading to the escalators up to platform level. Thus interchange can take place without having to go through barriers.

Facilitating passenger flow is important and the escalators are located in the centre of the platforms to give travellers easy access to the concourse when alighting from a train.

On the terminus side of the station, the present exit route is via barriers at the buffer stop end and this will be retained. However, access to the new street-level concourse is also required for interchange purposes and therefore, in addition to the Shard entrance barrier line, one escalator and one set of stairs per platform are being provided, the escalators being switched from running up or down according to the peak period flows.

Complementing the concourse will be an extension of the passenger information displays, which will use a destination-orientated style rather than showing actual train services. Thus, people wanting to travel must look for their destination station, which should then tell them the next suitable train and the platform number. Anyone who uses Manchester Piccadilly station will be accustomed to the concept.

The display boards are being arranged so that passengers congregating around them will not block the walking route for others. A new ticket office in the unpaid area is being provided with lots of ticket machines to ‘self help’ the process as much as possible.

Accessing London Underground’s Northern and Jubilee lines is all-important. The escalators from the terminus concourse have recently been taken out of use and

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Rail Engineer • August 2016

replaced with new ones near to the Shard building.

The former escalators are being demolished and the passageway extended into the street level concourse to give access to the new platforms.

The route of the passageway will be changed periodically as work to complete the concourse takes place over the next two years. The slopes from the ends of platforms 1-3 leading to the present Tooley Street entrance and the LU ticket hall are to be closed after August once these platforms are taken out of use.

In line with disability requirements, all of London Bridge station will have step free access with lifts supplementing the escalators and stairs to achieve this.

August Bank Holiday 2016

Before - six through and nine terminating platforms.

From Saturday 27 August until Thursday 1 September, new Platforms 7 to 9 will be brought into use to serve Charing Cross trains. At the same time, approximately two thirds of the new concourse will be commissioned with access from both the terminal and new higher-level platforms. This will include the escalators to platform level, customer information displays, the new ticket office, the introduction of the paid and unpaid areas, plus various retail / food outlets.

Throughout this period, Southern trains will run as normal into the terminus platforms. On the 27/28 August, there will be no trains to Charing Cross, Cannon Street or the London Bridge through lines, services being diverted to other London stations, principally Victoria. From 29 August until 1 September, a service will resume to Charing Cross. Cannon Street will remain closed until the end of the week.

Ongoing work Part of the bank holiday work will be to provide two through tracks on the site where the eventual Thameslink platforms will be, to enable access to Cannon Street station. These are needed as the existing London Bridge east side Platforms 1-3 to Cannon Street will be closed whilst rebuilding takes place over the next two years.

Once the bank holiday period is over, the restoration of a train service from London Bridge to Charing Cross will have limitations as only three tracks (Platforms 7, 8, 9) will be available. To obtain the optimum throughput, a type of contra flow system will be introduced in the peak hours. In the morning, trains coming out of Charing Cross to the South East will not stop at London Bridge; in the evening the situation will be reversed with trains going

Rail Engineer • August 2016

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into Charing Cross not stopping at London Bridge. This will facilitate the best means of achieving the necessary empty stock movements.

Work will then start in earnest to demolish the arches that support Platforms 1-3 and extend the new street level concourse northwards towards Tooley Street. By mid-2017, Platform 6 will be opened, thus creating two Down and two Up lines to Charing Cross and enabling the contra flow restriction to be lifted. In 2018, Platforms 1-5 will be ready, whence a service from London Bridge to Cannon Street will resume as well as restoring the Thameslink route through to Blackfriars.

Controlling the station One task already completed is the provision of a new control room, sited to overlook the new street level concourse. Network Rail has overall responsibility for the station operation, and all areas will be monitored using 600 cameras, these being viewed on a bank of screens that scroll round the various images in sequence. Should any alert or emergency occur, the nearest camera(s) will zoom in on the particular zone.

PA announcements will be largely automated, but with Southeastern staff being responsible for broadcasting any special messages to anywhere on the station. Duty managers from Network Rail, Southeastern, and Southern (including Thameslink) will sit alongside each other in the control room. New shared staff accommodation and messing facilities are in place, catering for some 280 people who will work the station shifts.

Some logistics When all is complete in terms of both station and track remodelling, Thameslink trains will pass through at two to three minute intervals, 16 an hour in each direction.

Automatic Train Operation (ATO) will commence in the London Bridge area to achieve the 24 trains per hour when combining all the routes through the Central London core. Charing Cross and Cannon Street services will obtain a much easier flow resulting in faster journey times.

The cost of the station rebuild is around ÂŁ1 billion which, when considering the work being carried out, is good value for money. The principal contractor for the station rebuild is Costain, with a multitude of sub-contractors working beneath them. The associated track and signalling work is contracted to Balfour Beatty.

Thanks to Chris Denham and Alexandra Swann of Network Rail for facilitating Rail Engineer’s visit to a busy worksite.

After - nine through and six terminating platforms.

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Rail Engineer • August 2016

A testing weekend at

DAVID SHIRRES

D

Stapleford

uring the first weekend in July, the Railway Division of the Institution of Mechanical Engineers (IMechE) held its fifth Railway Challenge at the Stapleford Miniature Railway, near Melton Mowbray. This was also the end of Rail Week, a pan-industry initiative, involving over 70 organisations, intended to show schools, teachers, career advisors and students the rewarding career opportunities across the rail sector. With the National Skills Academy for Rail estimating that the railway engineering skills gap currently costs £206 million a year, rising to £316 million by 2024, there is a great need for such initiatives.

Huddersfield team at work.

The Railway Challenge aims to attract young engineers into the rail industry. For the 73 competitors from seven teams, as well as around 200 spectators who visited over the weekend, it was certainly clear that railway engineering can be challenging, satisfying and fun, even if it has its frustrations.

Teams are required to design and build a 10¼ inch gauge locomotive to be tested against various performance criteria. They also have to submit a design report, present a business case and, new for this year, a short journal article explaining an innovative aspect of their locomotive.

The maximum points available for these challenges were: energy storage (300), traction (150), ride comfort (150), noise (150), maintainability (150), design (150), business case (150), innovation (150) and reliability (150).

Collecting the stickers For each of the track-based challenges, the winning team receives the maximum points. Other teams receive points in proportion to their performance against the winning team. Teams completing all tests without failures receive 150 reliability points. Any failures reduce this by 10 points, or 20 if assistance is required to move the locomotive.

Before a locomotive can do these challenges, it must pass scrutineering. This requires the collection of a set of six coloured stickers awarded when the scrutineer has confirmed the SAFETY calculations, the required INDICATIONS, that FUEL is protected and contained, the design CALCULATIONS are complete, the BRAKE operates to specification and static and dynamic tests DEMONSTRATE specification compliance.

Rail Engineer • August 2016

The technical specification is performance related and aims to stimulate innovation. Its key requirements are for self-contained motive power, a maximum speed of 15km/h, to operate on the track and loading gauge of the Stapleford Miniature Railway, to run for three hours without refuelling and refuel in 90 seconds. 95% of the materials used have to be recyclable. Control has to be by a remote unit so the driver can sit in a coach behind the locomotive.

New for this year is the need for the driver to have a tether kill cord and for locomotives to incorporate both lifting jacks and transverse jacking wheels.

The documentation required is a design report with performance, structural and wheel unloading calculations; a top-down and bottomup safety analysis; bill of materials; production and maintenance cost estimates; as-constructed drawings; operation and maintenance manuals and an innovation report.

When the first Railway Challenge was held in 2012, there were five challenges. Since then noise, maintainability, reliability and innovation challenges have been added. In 2015, there was an energy efficiency challenge, however this proved not to be practicable. With the lack of a prescriptive specification, the challenges have seen a wide range of innovative technologies. This year’s entries were no exception.

Introducing the teams Eight teams submitted entries this year. The University of Birmingham entered the first Railway Challenge in 2012 and has entered all subsequent challenges with what is probably the UK’s first hydrogen-powered locomotive. Unfortunately, this year Birmingham was unable to bring its locomotive to Stapleford, although it was given credit for the design report.

SNC Lavalin, formerly Interfleet is the only team to have been at Stapleford for every competition and won the first Railway Challenge with the first Derby-built locomotive for 45 years! This year, a team of twelve first-year graduates entered a completely rebuilt locomotive. It had a hybrid drive to charge both batteries and supercapacitors which drove four traction motors, one on each wheelset.

The University of Huddersfield had entered all the challenges since 2013 when, as a newcomer, it had won the event. This year’s team of twelve students had a unique axlemounted coil spring energy recovery system which, through an ingenious arrangement, could store energy in either direction. This year the brake band that locked the spring housing was replaced by a more-efficient tread brake. Another modification was the addition of a cardan shaft and bevel gear arrangement to transmit power between the bogie, enabling the single traction motor and energy recovery system to drive all wheels.

Transport for London (TfL) won the 2014 event with its first entry as well as the 2015 competition. This year’s team comprised eight graduates and four apprentices. Their TfL brandedlocomotive had a traction motor on

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Special judges' prize for the joint Bombardier/ Derby University team.

Sheffield do their maintenance challenge.

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Rail Engineer • August 2016

Southampton's locomotive under test.

each bogie with chain transmission to both wheelsets. Energy storage was by a hydro-pneumatic accumulator that drove a hydraulic motor on one bogie after being charged by a hydraulic pump on another bogie. It had a natural fibre composite shell which was the subject of the team’s innovation submission.

First appearing at the challenge last year was the University of Southampton. Its team of four finalyear and two third-year students was sponsored by Siemens, which had provided practical support at its

Eastleigh depot. Like TfL, all wheels had a chain transmission from a traction motor on each bogie. The locomotive had a hybrid transmission using supercapacitors for energy recovery.

2015 was also the University of Sheffield’s first time at Stapleford, although its locomotive was unable to complete the track challenges as it was prone to derailment on curves.

The thirteen mechanical engineering students on the team were confident they had solved this problem by redesigning the suspension. Instead of a central pivot, their bogie had radial arms which provided space for a mechanical recovery system to be developed for a future competition.

This year energy storage was by supercapacitors.

New entrants The hydrogen-powered locomotive from the University of Warwick was intended for last year’s challenge but the team ran out of time. Hence its team of six Masters of Engineering students already had the bogies and a fuel cell. That their diminutive locomotive was the lightest entry was not surprising as Warwick has centres for excellence in lightweighting and very light rail innovation. Although it looked small, the team had calculated that it could haul the required load in the technical specification. Its six lead-acid batteries provided both the required weight and a peak power output well above the steady charge of the 1.1 kW hydrogen fuel cell.

Another new entrant was a joint team of seven Bombardier graduates and four University of Derby students.

This was the first collaboration between academia and business and had to overcome the difficulty of the

different hours worked by students and graduates. Like TfL and Southampton, this locomotive had all-wheel drive with a single traction motor on each bogie. Although it had secondary air suspension, there was no compressor, requiring the use of an external pump to charge the air bags. The locomotive was fitted with hydraulic brakes and the energy stored in the supercapacitor was discharged through a secondary motor with a high gear ratio to run it at high speed, and therefore high efficiency, during energy recovery.

The design and production of these locomotives, with their complex supporting documentation, was an impressive achievement - especially as many of the team members had their final exams to consider. This was certainly the view of chief judge Bill Reeve, otherwise the commercial director for Transport Scotland, who congratulated all the teams for just being at Stapleford. He was pleased to see how the challenge had developed with better industry involvement and how lessons had been learnt. In 2012, three of the four locomotives were four-wheeled vehicles. This year, all seven locomotives had bogies.

During the weekend, a dozen or so senior engineers from the Railway Division acted as judges, scrutineers, controllers, marshals and in various other roles. In addition, the Friends of the Stapleford Miniature Railway (FSMR) provided the drivers, guards and signallers for the operation of competition trains, a backup locomotive and, on the Sunday, steam trains for spectators.

The miniature railway dates from 1958. In the 1960s, it ran boat trains to the Haven, the challenge’s spectator area, where passengers transferred to

Rail Engineer • August 2016

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45-foot long scale model liners, believed to be the world’s largest scale passenger boats. Here, in a 1965 episode of the cult TV series The Avengers, John Stead rescued Emma Peel as she was tied to the tracks in front of an approaching train.

Normally closed to the public, the railway has a couple of open weekends a year, the next one being 27-29 August. With three kilometres of track, a balloon loop, a maximum 1 in 80 gradient and space for teams to work on their locomotives, it is an ideal location for this miniature recreation of the 1829 Rainhill trials.

Testing times Locomotives were unloaded from their vans on Thursday evening and the following morning. Friday was the day for scrutineering and some test running. It also saw the first on-track challenge, the maintainability test. This was judged on the time taken for teams to remove and replace a driven wheelset with penalties for any safety infringements. This varied between SNC Lavalin’s impressive 3 minutes 17 seconds to 35 minutes 34 seconds.

Saturday saw further scrutineering and the business case challenge. This required teams to face executives of a large company (in this case, the judges), which wished to procure fifty locomotives for commercial operation on its 10¼ inch gauge tourist railway, and present the case for their machine. To do this, teams had to show how their designs met the customer’s demands and were cost effective, taking into account both operational and maintenance costs.

Further test runs during the day were not without incident.

One locomotive was unable to restart and had to be pushed back to the station by FSMR’s rescue locomotive. There were two derailments, one after a locomotive ran over an exhaust pipe that had fallen off, and another because wheels had moved on their axles. This showed the wisdom of the new requirement for jacking wheels which were used to move the locomotive off-track to avoid delay to other test runs.

A challenging Sunday For the Sunday, there was an operational plan to ensure that eight locomotives could complete their on-track challenges whilst hauling a trailing load (a coach with driver, judge and guard). This allowed for four train movements (two competing locomotives, a rescue locomotive and spectator train) every hour. In the event, this detailed planning was not necessary as three teams were unable to compete, despite working well into the early hours of Sunday morning.

Warwick had spent much of the weekend assembling their locomotive and ran out of time to make it operational.

Although the Huddersfield locomotive had performed well during the previous day’s tests, its Rockwell controller had failed. Sheffield was also having electrical problems that taxed its team of mechanical engineering students. In previous challenges, voltage spikes from petrol generators had proved too much for control electronics.

Team Warwick's maintenance challenge.

(Below) SNC Lavalin's prize winning locomotive.

(Inset) SNC Lavalin team with their trophy.

74

Rail Engineer • August 2016

LOCO SHED

HAVEN CAFE

STATION

HAVEN BRIDGE

TOP CURVE CARRIAGE SHEDs

PLATELAYERS

COLBY’S CULVERT

LOCO SHED

The Fin al S cor e LAKE SPILL WAY

TUNNEL

BADGERS BEND

TOP CURVE

CARRIAGE SHEDs JENNY’S BRIDGE

PLATELAYERS

RIVER EYE

TUNNEL

SCALE (METRES)

0

150

300

SCALE (METRES)

0

150

By midafternoon, the judges retired for their deliberations after which Bill Reeve announced the scores as:

TfL with their locomotive.

It was notable that the locomotives that were unable to compete had not been tested on another miniature railway.

One such team advised that they had only separately tested individual systems. The need to test locomotives under power as they rattle over a miniature railway’s curves and points was a lesson from this, and all previous challenges.

The teams had 45 minutes to complete their four on-track trials. The first was the ride test for which an accelerometer was magnetically fixed on the locomotive body to determine ride comfort in accordance with British Standard BSEN 12299:2009 whilst the locomotive went around the one kilometre balloon loop. The ride comfort index for the competing locomotives varied between SNC Lavalin’s winning 1.21 and 7.27.

Next was the energy recovery challenge, in which locomotives stopped at a defined point using their energy recovery braking system. The stored energy was then used to run as far as possible whilst demonstrating to the riding judge that the only power was from the energy recovery system which did not gain any energy during the move. Only SNC Lavalin and TfL could satisfy this latter requirement.

Their locomotives ran, respectively, for 7.14 metres and 1.48 metres, a third challenge win for SNC Lavalin.

Noise and traction challenges were undertaken simultaneously at the bottom of the 1 in 80 gradient.

Whilst the locomotive went through its traction challenge, both starting and pass-by noise were measured. Half the available marks were available for each. Starting noise varied between 80.8 and 83.4dB, whilst pass-by noise was between 85.3 and 91.4dB. The noise challenge was won by the Bombardier/Derby University team.

During the traction challenge, the riding judge used an iPad accelerometer app to determine the maximum acceleration, averaged over one second, between the starting and by-pass noise microphones. Previously this challenge had measured time taken. However, with locomotives soon getting to their 15km/h maximum speed, there was little difference between the times. Hence acceleration was considered to be a more meaningful measure. Acceleration varied between 0.53 and the 1.40m/s2 achieved by Southampton, which won this challenge.

Many thanks to the FSMR for their unstinting support throughout the weekend and to the IMechE Railway Division for unfettered access to the event.

Teams interested in entering the 2017 Railway Challenge need to register their interest with IMechE by the end of 2016.

1st | SNC Lavalin - 2nd | TfL - 3rd | Southampton Uni - 4th | Bombardier/Derby uni - 5th | Huddersfield Uni - 6th | Warwick Uni - 7th | Sheffield Uni - 8th | Birmingham Uni -

HAVEN CAFE

STATION

1291 789 680 606 283 256 221 107

In what he described as a “stonking performance”, Bill then confirmed that SNC Lavalin had won by quite a margin (1291 points) with a locomotive that had performed flawlessly throughout the weekend.

The prize cup was presented by IMechE pastpresident Richard Folkson.

New for this year was the judges’ prize, awarded to a team for a particularly impressive achievement.

Bill announced that this year the judges were awarding this prize to Bombardier/Derby University which, as a new entrant, had done particularly well and was a successful example of a joint industry and university team.

The IMechE’s Railway Division has put much thought into the challenge’s evolving rules and technical specification and its members devote much time to ensure the success of the event. It is also important to recognise the FSMR’s essential and enthusiastic contribution.

A measure of the challenge’s success was the teams’ commitment, ingenuity, hard work and innovative approach. Their camaraderie was also evident from the sharing of tools and equipment.

Whilst some locomotives were not able to enter the challenge, this is a reflection on the complexity of railway systems engineering rather than the ability of the team. Frustrating though such failures are, they provide an invaluable learning experience.

The teams clearly had fun and many said they enjoyed themselves more than they expected to.

Perhaps they will now be attracted to a railway engineering career. If so, the Railway Challenge will have been truly successful. Yet with the urgent need to attract more rail engineers, more needs to be done to promote and support this event and other such initiatives.

300

76

Rail Engineer • August 2016

Force in Rail R An emerging

eaders might recall that the early part of 2015 was extremely wet, even

by UK standards. As a consequence of this extreme, inclement weather, there were a number of locations on the railway network that suffered badly from flooding and/or instability of railway cuttings and embankments.

One of the many articles published by Rail Engineer during this wet weather period was on the 350,000 tonne landslip that extended more than 150 metres through a cutting leading up to a tunnel portal at Harbury (issue 127, May 2015).

As a consequence of the landslip, the line between Leamington Spa and Banbury was closed for six weeks causing major disruption to passengers travelling between Oxford and Birmingham. Network Rail called on the skills and expertise of its emergency earthworks contractor, J Murphy and sons, to stabilise the embankment and restore the track formation in order to allow the 50 freight and 80 passenger trains that use the route every day to recommence their services.

Although the weather conditions continued to be unsympathetic to the challenges facing the engineers, the route was restored in less than six

COLLIN CARR

weeks - much to the relief of Network Rail and the travelling public.

A more sophisticated monitoring system than previously used was installed on the embankment slopes and around the tunnel portal. This included 80 wireless slope sensors and wall sensors for the tunnel portal.

These sensors were designed to detect any future microscopic movement and the information produced was made available, and continues to be made available, to Network Rail around the clock.

Throughout this period of work, more than 320,000 tonnes of earth has been removed from the slip area using a fleet of Moxy dump trucks and excavators provided by various plant suppliers.

The aim was to move the toe of the embankment 30 metres away from the tracks, thus removing the fault line and re-profiling the embankment. A further 150,000 tonnes of earth has also been removed from further along the cutting to stabilise the embankment.

A more permanent solution needed

Before re-opening the route to trains, design details were signed off, revised slope angles achieved, dewatering levels met, signalling tested, track alignment surveyed and structural checks of the tunnel portal carried out.

However, it was recognised that a more permanent solution was still needed.

To this end, Murphy has remained on site as the principal contractor.

The design services of Tony Gee and Partners have been engaged to provide a more permanent solution, focussing primarily on the Harbury tunnel portals.

In addition, Murphy has acquired the services of Force Contracting Services Ltd. This company started out in 2007, primarily as a fencing contractor, and managing director Ben Layden has grown the business, which now works in a number of industry sectors throughout the UK. Based in Nottinghamshire close to the M1, Force is in a good position to respond rapidly to a client’s needs, whether they be fencing, de-vegetation, civil engineering or construction. It employs more than 50 staff and has only recently entered into the railway sector over the last three years.

Tel: 01909 509475

info@forcecontracting.co.uk www.forcecontracting.co.uk

With many years of experience, Force Contracting Services offer a multi-disciplinary team. Working on the National Electrification Programme (NEP) and CP5 (Structures & Earthworks) helping to transform railway. Force are a family lead business always willing to tackle any challenge no matt .

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78

Rail Engineer • August 2016

Stabilising embankments The bulk of the work currently underway is situated around the tunnel portals where there is still concern about potential movement and the level of instability that still exists. Under the guidance of project manager Jim Broe. the work that Force is carrying out for Murphy involves the installation of approximately 300 soil nails above the tunnel entrance and around the portals. Access is challenging and the slopes are steep. A specific level of expertise is required to gain access to the site, position the drilling rigs and carry out the challenging task of soil nailing on such a steep embankment.

Therefore, Force is using a specialist team to carry out this work. This involves using a team, highly trained in rope access procedures, to abseil down the slope, position the drilling rigs and then drill a 100mm diameter core, approximately six metres long, into the tunnel portal embankment.

A 32mm diameter reinforcement bar is inserted into the bore, which is then back filled with grout and finally plated. Offsetting the anchors helps to lock the ground by creating friction between the soil and the grout, ensuring that the embankment remains stable. Finally, a geotextile wire mesh is being fixed to the anchors to cover the whole embankment and provide further stability.

To complement this work, Force has constructed a new drainage channel around the top of the tunnel portals to capture water flowing off the embankments. In addition, a Kee-Klamp handrail has been installed to follow the profile of the portal and offer safe access for inspection and clearing vegetation in the future.

To further improve access to the tunnel portal areas, Kwik-Step access steps are being introduced that will start on firm ground at the

top of the portal embankments and finish at the bottom of the embankment over the crown of the tunnel, a task that requires considerable care and attention given the location.

Shotcreting embankments The major slip did considerable damage to the wing walls of the tunnel portals and it was decided that stability would be ensured by nailing and shotcreting the embankments that were previously supported by those portals.

This would not only provide stability but would also negate the need to rebuild the wing walls concerned.

Finally, the brickwork around the tunnel entrance had been repaired by previous generations who decided that, instead of renewing the brickwork, they would spray concrete over the weathered brickwork to protect it. Unfortunately, this protection has now become life expired so Force has been instructed

by Murphy to remove the crumbling material and expose the sound brickwork behind, which

would then enable specialists Gunform to shotcrete the area during a key possession planned in August.

All the above work is well underway and nearing completion, with the August possession being the final key milestone. The intention is for all the work to be finished in September by which time all the contractors should feel proud of what they have achieved following on from one eminent railway engineer, I K Brunel, who built this railway.

The railway first came to the village of Harbury in 1847 as part of the construction of the main Oxford to Birmingham GWR line. The cutting is located to the north of the village and at the time it was considered to be a significant engineering feat. At over 34 metres deep, the cutting was the largest man-made cutting in the world that was dug entirely by hand through blue lias clay. It was completed in 1852.

Today, Murphy, Force and others are helping to ensure that this railway will last for several more generations.

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80

Rail Engineer • August 2016

Engineering

NIGEL WORDSWORTH

T

directors gather

he railway runs on engineering. Indeed, it was built and developed by engineers. George Stephenson (Liverpool and Manchester Railway 1830), his son Robert (Stockton and Darlington Railway 1825), Isambard Kingdom Brunel (Great Western Railway 1838) and William Barlow (St Pancras station 1868) were all notable civil engineers while the likes of George Churchward (GWR 1902-1922), Sir Nigel Gresley (GNR/LNER 1911-1941) and Oliver Bulleid (Southern 1937-1948) produced outstanding locomotives.

We don’t have those famous names today.

Designs are produced by teams, often by collaborations, so the days of the world-renowned engineer are, perhaps, over.

Nevertheless their successors, the engineering directors of the companies which design, build and maintain the railway, are still important people.

So when the engineering directors of designers and consultants such as Amey, Arup, Atkins, Jacobs, Ricardo Rail and WSP-Parsons Brinckerhoff, all busy people, gather together in a meeting room at the Hammersmith offices of CH2M, something must be going on.

Now add into the mix the engineering directors of contractors ABC Electrification, Alstom Signalling, Graham, Morgan Sindall and TSP (Balfour Beatty, Murphy and Siemens sent apologies) and the plot thickens.

As the industry’s leading reporter on all things engineering, Rail Engineer was there as well. So too was Network Rail’s engineering director of Infrastructure Projects, soon to be chief engineer of the whole group, Jon Shaw. He chaired the meeting.

So what was it all about?

The gathering was nothing less than the second meeting of the Engineering Directors’ Forum.

This gives the industry’s senior

Typical GeoRINM views of the infrastructure.

engineers a chance to discuss mutual problems, air concerns, seek solutions and agree joint actions in an open and frank forum without, in any way, impinging on the fact that they are normally ultracompetitive.

The quality of technical information passed from client to contractor, the need to give young graduate engineers a rounded education in all facets of the industry, the fate of TSIs (technical specifications for interoperability, drafted by the European Railway Agency on behalf of the European Commission) - these are all topics of mutual interest that don’t conflict with the need for companies to remain independent and competitive.

Risk and opportunities A lot of the discussions are not for repetition on here. Not because they are particularly secret, but comments, suggestions and half-formed ideas for later consideration shouldn’t be reported until they come to fruition - or not at all if they are then discarded.

However, five areas did get discussed in detail and these will form the basis of future actions by the forum. They represent the five greatest risks - and opportunities - going forward.

Early involvement This may be an old chestnut, but it is still a very relevant one. As was recorded in the meeting notes: “There is an opportunity to optimise engineering programme delivery if the contractors are involved earlier in the GRIP stages and there is time available in these early GRIP stages to fully explore options and robustly define requirements.”

But the discussions were more than just about early involvement. The whole planning process, and the need to complete one stage before the next is commenced, was on the table. Designers get frustrated when contractors start building a project before the designs are complete. Similarly, contractors hate being forced to start construction that hasn’t a completed design as it leads to changes which then give rise to increased costs, overruns, and arguments with the client.

So everyone was in agreement that time has to be given to complete the design process properly. This will make it easier, and quicker, for construction to take place - a consideration that has been taken fully on board in the plans for building HS2.

Jon Shaw outlined his vision of a technical stage gate process. Similar to the GRIP programme, and complementary to it, the new process will force certain levels to have been reached before the design, and the project, can move on to the next stage. One of these is a robust definition of the project’s goals and requirements, as well as a close connection between the development and delivery teams to ensure that a whole-system view is taken.

A working group, led by Atkins, will take these ideas a stage further before the next meeting of the Forum in November.

Rail Engineer • August 2016

81

Asset data Network Rail has a lot of data on its assets - most of them anyway. Maps, aerial views, plans, technical drawings, condition reports, maintenance records - there is any amount of them.

And they are stored in databases all over the country and, in many cases, not joined up.

So a designer, when presented with a new project, goes out to perform another survey of the area and assets. This necessarily has a cost attached, and puts surveyors on the railway potentially in harm's way, and it is very often a duplication of information that already exists.

Why do they do it? Because they can’t take the risk that the Network Rail information is up-todate and complete. Any fault, and the blame, as well as associated rectification cost, will come down to them - the designer and contractor. So they do another survey.

Network Rail therefore needs to have an up-todate register of all infrastructure assets, and their condition, which it can make available to designers and contractors. The latter must also, in their turn, make sure that all asset registers are updated following the work they have undertaken.

Once it is confident of the accuracy of its information, Network Rail can then take the risk, so no-one has to repeat the process.

This all falls in line with the work being undertaken by Network Rail’s ORBIS team, together with its GeoRINM programme.

Representatives will be asked to address the next Engineering Directors Forum and a working group, led by Rail Engineer, has been established to develop high-level industry rules for asset information exchange.

Regulations and standards There is a risk to engineering programme delivery due to a lack of consistent application of standards and regulations. The whole subject of standards is a minefield. There are British, European and International standards (BS, EN, ISO), railway group standards, notified national technical rules (NNTRs) and technical specifications for interoperability (TSIs). Network Rail has its own standards and there is even IRIS (International Railway Industry Standard).

Are they all applied correctly? And will European standards even be applicable in two years’ time?

It was time for another working group - this one to be led by Jon Shaw himself.

Talent pipeline When the railway was one integrated whole, young engineers could obtain experience of a wide range of disciplines before they chose a final career path. Today, with companies providing a finite range of services, that is no longer possible.

A trainee designer may never go on site to see

how the railway is actually built, while a graduate in a trackside team will have no idea how that job was planned and designed.

Some companies already ‘swap’ graduates, to give them cross-industry experience. But not all do.

Do all new roles need to be for university graduates anyway? Is the apprenticeship route more appealing and likely to produce a betterrounded individual and a more flexible workforce?

And what is a qualified person? Is there a need for a recognised accreditation/licensing scheme for key CDM (construction design and management) roles for consistency of authorities, similar to the licencing scheme for signal engineers?

The ‘peaks and troughs’ of railway workload also cause a problem. One day a company needs all of the engineers it can get its hands on, the next it is hopelessly overstaffed. How does this affect engineering day rates/remuneration, retention of competencies and development?

This working group is to be led by Morgan Sindall, which has a keen interest in this area.

Whole-life delay The fifth area discussed was the issue of wholelife costing, how it can save money in the long term but be more expensive initially, and how that fits into a railway that is striving to reduce up-front costs. It was a popular topic, but one which sadly ran out of time.

Will the apprenticeship route be more likely to produce a flexible workforce?

Typical GeoRINM views of the infrastructure.

Further discussion will therefore have to wait until November, when the third meeting of the Engineering Directors’ Forum will take place in Birmingham. In the meantime, this second gathering had been an unqualified success. Ardent competitors were volunteering to sit on the same working groups while contractors and designers were arranging, over coffee and sandwiches, to exchange graduates and trainees for the wider benefit of the rail industry.

All in all, it was a useful day and one well worth repeating. Brunel and Churchward would have been proud.

Now where did I put ORBIS’ phone number?

82

Rail Engineer • August 2016

MALCOLM DOBELL

Improved

transmissions for 158s I

t is no exaggeration to say that the Cummins engine, Voith T211 hydrodynamic gearbox and Gmeinder final drive helped to transform diesel multiple unit performance in the UK during the 1980s. Over 2,500 examples of the T211 transmissions (out of 40,000 worldwide) are fitted to nine classes of British DMU, including the Pacers and class 15X units.

In those days, reliability and performance were valued above all else and the Voith T211 transmission delivered that requirement. Fuel economy and CO2 emissions are now much more important, and hydromechanical drives generally suffer higher losses than mechanical transmissions under certain operating conditions.

Parallel path To respond, Voith now offers the DIWARail (pronounced DivaRail) hydro-mechanical gearbox. It is based on an automotive product of which many thousands are in successful operation. In principle, this is a torque converter combined with a four-speed epicyclic gearbox.

The clever part is that there is a parallel path to transmit torque between the input shaft and the gearbox – a direct drive and via a torque converter in first gear.

These are connected to the gearbox that is controlled to allow the mechanical drive to take over gradually from the torque converter as input speed rises until the point that the less efficient torque converter is completely locked out of the drive train.

This Power-Split principle in first gear allows a higher range for starting that eliminates the second gear stage of comparable transmissions and ultimately reduces the number of gear changes by up to 50 per cent.

Over 2,000 DIWARail transmissions - the rail version - have been used since 1993. The latest incarnation has had a patented, integral reversing gear added to the rear of the gearbox. Clearly this is not needed on the automotive version as trucks and buses are not expected to be able to operate at full speed backwards! Some 150 of these transmissions have been delivered.

Service trial To demonstrate the performance and economy that the gearbox offers, Voith fitted a Class 158 DMU with two DIWARail transmissions for an in-service trial in collaboration with Angel Trains (the owner) and Arriva Trains Wales (the operator). The aim was to demonstrate that the hydro-mechanical transmission would be reliable, improve efficiency, and reduce fuel consumption compared to the currently installed transmissions. The trial has been running since June 2015 with over 150,000 miles already accumulated.

During a recent meeting of the Railway Industry Association’s Traction and Rolling Stock Special Interest Group, Voith’s Dave Taylor described the project and the results to date.

He said that the trial has been commissioned as a collaborative venture to demonstrate and evaluate the benefits of the new transmissions for fitment on UK DMU fleets.

Voith provided a turnkey installation covering design, manufacture, project management, installation and commissioning. Besides the DIWARail transmission, Voith also delivered a control system, all brackets and guards, Voith ‘one million mile’ cardan shafts and a new hydraulic torsion vibration damper (Hydrodamp).

The primary business driver for the trial was to reduce fuel consumption, due to the more efficient transmission, and the result has been a reduction of maximum fuel consumption by up to 16 per cent. Depending upon the duty cycle of the particular route, this figure could be increased further. Generalising, the more frequent the stops and starts, and the lower the average train speed, the better the improvement in fuel consumption.

Rail Engineer • August 2016 In addition to reducing fuel consumption, which is accompanied by a drop in all engine emissions (16 tonnes carbon reduced/year), the DIWARail transmission offers a weight saving of over 220kg compared to the currently installed transmission and a saving of over 150 litres of oil over the life of the transmission due to lower oil change frequency. This latter also removes the need for two oil changes, with the accompanying reduction in labour costs.

The installation of the Voith Hydrodamp moves the critical natural frequencies in the driveline below the operating speed and hydraulically dampens torque peaks. This protects all connected system components against harmful vibrations and thus increases their life and availability.

Complete success Voith fitted the components on both cars of the class 158 units in just 13 days – half the time agreed with the partners in the project. The train was released for its first main line run on the following day, giving a total project fitment time of just 14 days for return to service. A significant contributory factor to the rapid return of the vehicle to revenue-earning service was the support and flexibility of the ATW staff at Cardiff Canton depot working in conjunction with Angel Trains.

Construction of a full-scale mock-up

of the complete system to ensure that the final items would fit when delivered early in the design phase helped de-risk the installation.

In the 12 months since the trial started, the performance has been assessed on a number of different duty cycles to validate the modelled performance. In addition, a remote monitoring system – DIWA SmartNet has been used to assess performance information about the gearboxes remotely.

Dave Taylor said that the trial has been extremely successful and the two transmissions are running in daily service with no problems accumulating jointly over 25,000 miles each month.

There have been no reliability issues, and fuel consumption has been in line with the forecasts. In short. this project clearly demonstrated the benefits of introducing modern and more efficient transmissions as a retro-fit concept.

He added that designs are also being developed for other British DMU modernisation projects where the Voith

DIWARail transmission can be used in conjunction with new or existing diesel engines. Clearly these benefits are available for new build too.

Dave Taylor concluded that Voith is the only supplier who can offer a complete integrated driveline from a single source. The scope of supply can also be extended to include replacement final drives, RailPack (complete raft mounted engine/ transmission/cooling system) drive packages and cooling units, all of which can be sourced from Voith.

83

84

Rail Engineer • August 2016

Advanced energy management

TONY AMIS & MIKE BEAGLE

F

or many decades, the area south of the Grand Union Canal at Old Oak Common in West London has included 100 acres of railway lines, sidings and depots as well as down-at-heel industrial estates. However, it is currently undergoing regeneration and 25,000 homes and 55,000 jobs are due to be created there over the next 15 years.

This development will result in 250,000 passengers a year using a transport super-hub with proposals for Elizabeth line (née Crossrail), HS2, Tube and Overground stations all close to each other.

There will also be an Old Oak Common depot for the Elizabeth line. Existing railway land will be redeveloped to construct a new rail maintenance facility including a nine-road operations, maintenance and control (OMC) building. One of the roads will be fitted with jacks which will be able to lift an entire train.

The new depot will also include offices for both Bombardier, the train maintainer, and MTR, the operator of Elizabeth line services, as well as providing 33 stabling sidings.

The London Plan challenge The project has demonstrated the importance and benefits of early contractor involvement and collaboration from bid stage through to construction. A team of engineers from Bombardier, main contractor Taylor Woodrow, GI Energy and NG Bailey has worked closely together on the project for the past three years.

From the original bid proposal, the integrated team has since developed the detailed engineering design and is now overseeing the construction of the new depot building at Old Oak Common that will enable Bombardier to operate and maintain the new trains for 32 years once the railway opens from 2018.

The initial project concept design did not meet the required planning consent’s thresholds for CO2 savings and the use of renewable energy. Taylor Woodrow, GI Energy and NG Bailey worked together to create a solution that exceeded the 20 per cent target reduction in CO2. The workshops that took place for the development of the M&E design followed the London Plan’s policy of Be Lean> Be Clean> Be Green.

Defined in the current London Plan of March 2016, the project team took the following steps to comply: Be lean: use less energy »» Insulation levels were increased in the OMC building; »» Thermal mass of building utilised - floor slab; »» On-site plant use was reviewed and energy efficient options selected; »» Boilers downsized to single system standby.

Be clean: supply energy efficiently »» LED lighting is being installed throughout the site; »» Use Low to Zero Carbon Technologies (LZCT) where possible, supplement or replace energy hungry systems; »» Combined Heat and Power (CHP) units to be installed to provide high temperature heating and electrical demand.

Be green: use renewable energy »» Use a range of renewable energies; »» Ground-sourced heat pump (GSHP);

Rail Engineer • August 2016 »» Include solar photovoltaic and solar thermal solutions; »» Supplement and widen low energy solutions (provide under-floor heating and cooling); »» Integrate systems and appoint lead energy controller - capture waste heat from CHP and transfer into geothermal ground loop.

A series of workshops resulted in a solution that would deliver over 30 per cent renewable energy using a clever integration of CHP, solar photovoltaic and thermal with GSHP that enables any surplus heat to be stored within the ground loop, thereby reducing the client’s operational costs and increasing CO2 savings significantly.

This integrated design development enabled the team to exceed the original brief whilst maintaining its objectives. A scheme was developed that provided for all energy production to be integrated into a single solution to meet the energy demands of the project.

Collaborative design The enhanced design initially used 466 foundation piles as geothermal piles supplementing 25 closed-loop deep bores.

This was amended during refinement of the structural design to 366 geothermal piles and 52 150-metre-deep bores twinned with GSHP to provide 900kW of heating and 780kW of cooling.

These are supported by two CHP systems delivering 420kWth heating and 290kWe of electrical load along with 1500 square metres of PV cells providing 220kW on the roof of the OMC and 170kW of solar thermal panels.

In total, 54 per cent of the new depot’s heating and cooling will be provided from renewable technologies and 20 per cent of electrical load will be generated on site from CHP/solar PV, providing the depot with an overall 33 per cent renewable energy solution.

The depot’s design divides the building into two service zones, providing flexibility for moving energy throughout the main building.

In addition, the recharge cycle introduced a cooling opportunity into the underfloor heating system, making Old Oak Common probably the first UK railway depot with underfloor cooling throughout the workshop.

The energy piles sit in London Clay, which will be used as an energy store, retaining thermal energy from both production and regeneration for use when building demand requires it rather than losing this to the atmosphere. This

85

supports the incorporation of CHP plant into the design, which provides a constant thermal output for hot water, with any over-production stored in the ground, and also provides a parallel electrical generation for non-essential electrical services.

The innovative underfloor heating and cooling system has been expanded to cover the majority of the building, including both workshop and accommodation areas, and is all fed primarily from the GSHP system. Low-temperature radiators have been added in areas where raised access floors make the use of underfloor heating circuits difficult. These are also fed from the GSHP system, thereby reducing the demand for gas-fired boilers to serve conventional radiators.

This has resulted in almost entirely removing conventional space and water heating from the design.

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Rail Engineer • August 2016

Integrated system The use of multiple energy sources, along with connecting the north and south lowtemperature thermal circuits, enhances the system resilience as thermal energy can be transferred between the north and south mechanical systems.

The technical team has developed the solution in collaboration across both distribution and controls disciplines, enabling the development of a single integrated design that optimises the generation, storage and use of energy.

By making use of the seasonal cycle of heating and cooling, along with regeneration of the geothermal mass, green cooling has been introduced into the majority of the building and the system provides underfloor and low temperature radiator heating and cooling throughout (with the exception of a few temperature-controlled areas using conventional air conditioning).

Whilst the use of renewable technologies is now widely employed, the scheme for Old Oak Common depot is unique in the extent and integration of system technologies, the use of a thermal store, and the provision of heating and cooling through low-temperature distribution to both the accommodation and maintenance areas. The individual systems are tried and tested, the innovation is in developing a renewable-systems design which fully integrates separate systems to provide an holistic energy solution, switching between energy sources as demand and availability dictates.

The system development provides the following direct benefits: »» 50 per cent renewable energy provision exceeded requirements for 20 per cent provision; »» 65 per cent reduction in CO2 production exceeded planning requirements for 20 per cent reduction;

»» A net increase in the CAPEX for building services of approximately five per cent which yielded a net reduction in the OPEX costs of approximately 33 per cent of the building services CAPEX (and providing a projected 1500 per cent return on investment) ; »» It is anticipated that Bombardier will save some 17,000 tonnes of CO2 over the 32-year life of the building.

Of significant importance will be the sophisticated control system that GI Energy has developed and designed to optimise the integration of the renewable technologies installed. This will actively maximise both annual run-cost savings and CO2 savings and, at the same time, enable remote monitoring.

It is believed that, through the long-term management and optimisation of the system, performance can be significantly enhanced, improving savings by up to 10 per cent from that currently stated.

Energy partner As the market leader in the UK, GI Energy has considerable experience designing and installing renewable energy solutions, having installed more than 250MW of renewable energy solutions in schools, hospitals, universities, supermarkets, commercial

developments, housing associations and railway infrastructure since its inception in 2000.

GI Energy recognises the need to offer turnkey solutions to clients utilising the most appropriate renewable solutions to best deliver their objectives for each project. The company’s role, acting as an ‘Energy Partner’, is to ensure it offers the best possible solution for every scheme. GI Energy was recently voted Heating and Renewables Installer of the year and more recently the Old Oak Common project was voted Renewable Energy project of the Year by H&V News.

The design concept has been embraced by TfL as part of its aspirations for a Green Railway.

The collaborative approach has delivered a truly innovative sustainable hybrid renewable energy system, breaking the boundaries and setting a new benchmark in delivering renewable energy projects. The system has exceeded client and planning requirements and delivered significant monetary and environmental savings, which will be used as best practice to deliver the same benefits to future projects.

Tony Amis is business development director at GI Energy and Mike Beagle is senior M&E manager at Taylor Woodrow.

GI Energy founded in 2000, has installed some of the largest and most innovative renewable systems in the UK, installing over 250MW of capacity nationally.

GI Energy, market leaders of large scale renewable energy solutions, has evolved to become the complete energy partner of choice, offering a range of integrated renewable solutions from design through to installation and importantly long term management and system optimisation, controlled through our own in-house BMS system.

Working in the commercial market, GI Energy has delivered renewable energy solutions to Offices, Retail, Supermarkets, Hospitals, Schools, Colleges, Universities, Railway Stations and Depots.

Call us today for a free feasibility assessment on your project...

Tel:

+44 (0) 24 7685 0403

Email: enquiries@gienergy.net Web: www.gienergy.net

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Rail Engineer • August 2016

UK's most advanced

Carriage wash

C

airn Cross Civil Engineering Limited and Airquick Limited, working in partnership and on behalf of Network Rail and Arriva Trains Wales, have successfully completed the UK’s most advanced carriage wash system.

This multidisciplinary design and build project was awarded to Cairn Cross Civil Engineering through the development of innovation and value engineering. One of the aspects of value engineering that helped Cairn Cross become the preferred contractor was the use of existing assets and minimising the disruption to day-to-day depot operations.

There were many considerations the design team had during the design phase of this project, including passive provision for overhead line electrification and waste water separation to conform with recycling targets.

Airquick carriage wash The carriage wash installation at Holyhead is unique in that the specification called for a front and rear cab-end cleaning facility that can operate during a single pass of the train through the wash. The cab-end cleaner has to cater for varying stock from a vertical front to a sloped front of varying angles. Added to the complication is the passive provision of an overhead line running through the wash which excluded the option of a gantry type unit.

The carriage wash machine is a single pass unidirectional unit which incorporates 12 full-body-side

brushes on pneumatically operated fully retractable C-frames to allow for the varying stock profiles.

High-density polyethylene brushes of varying diameter are fitted to each shaft to ensure the profiles of the various carriages are washed efficiently, each being driven by helical worm gear motors with a rotational speed in excess of 200rpm.

The relatively narrow footprint of the wash required the installation to be as compact as possible whilst still achieving the required cleaning standard demanded by Network Rail.

Also featured on the wash is the use of a partial water-reclaim system that recycles the wash water and rinse water for the pre-wet and main wash sprays, thus improving efficiency and conservation of water. The reclaim unit also incorporates biocide injection to minimise the possibility of microbiological growth within the system.

The wash discharges wash/rinse water to an above ground three-stage interceptor, with a total capacity of eight cubic metres, where the settled water is drawn from the third chamber of the interceptor into the recycling plant.

The pre-wet and detergent water is not returned to the recycling plant, it is captured and discharged to a separate drainage system.

Design and build specialists Specialising in providing a for UK infrastructure and complete package of transport services Cairn Cross Civil Engineering Limited specialises in design and build projects for UK infrastructure and transport. A significant proportion of work is undertaken on rail related projects, including working within the rigorous demands of engineering possessions.

Cairn Cross Civil Engineering Limited has devoted a high level of resource and effort to develop and maintain a full Health and Safety, Quality and Environmental Integrated Management System which ensures a structured and detailed approach to planning and management of all works from concept to completion.

Innovation and value engineering are imperative to providing the client with the best possible solution.

1 Cadman Court, Morley, Leeds, LS27 0RX +44 (0)113 284 2415 • info@cairncross.uk.com • www.cairncross.uk.com

Cairn Cross Civil Engineering Limited. Registered in England and Wales 03110217 • VAT No 566419417

Airquick is a leading supplier of rail depot plant in the UK. We specialise in providing a complete package of services for single and multi-discipline systems; from design, through installation and maintenance of • Carriage washing systems • CET and LFA systems • Fuelling systems • Oil and coolant systems and top-up bowsers • Compressed air systems For further information and to discover our full range of services contact us today

Brunel Business Park, Jessop Close, Newark, Nottinghamshire, NG24 2AG 01636 640480 • sales@airquick.co.uk • www.airquick.co.uk

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Rail Engineer • August 2016

Detergent and final rinse water is provided directly from the mains water storage tank to ensure that cleaning standards are met.

Unipart Rail TrackPan The TrackPan system is a pollution control measure which ensures all contaminants are disposed of or recycled correctly. It can be installed at any location where there is a risk of a spill of diesel, gasoline, chemicals, oils, contaminated water, effluent or any other liquid polluting the underground and surrounding environment.

Custom-fit to the design of the carriage wash shed, this modular system not only assists in the partial water reclaim system but also removes the requirement for the lifting and relaying of existing rail track following a spill, therefore mitigating any disruption to potential depot movements.

The use of GRP material removes any concerns about interactions with OLE. The TrackPan integrated floor mesh provides a flat, even, anti-slip surface within the wash reducing the potential of any slips, trips or falls.

With a design life of 20 years, this robust product is ideal for use in demanding depots. When compared

to traditional concrete and steel solutions, it provides Network Rail and the operator with a costeffective low-maintenance solution for environmental issues relating to contaminant spills, along with providing easier access for rail inspection.

Any requirement to relocate this system is achievable due to its modular design and assembly.

installation, simplicity of use and maintenance along with overall performance.

“Throughout the project, there has been a proactive ‘can do’ attitude to push the project forward to complete within time and budget with no safety incidents. The project team has engaged in a professional manner with all stakeholders.”

Network Rail

Star Lite Award

Peter Caulfield, project manager with Network Rail Infrastructure Projects in Wales, said: “It’s been a pleasure working with Cairn Cross Civil Engineering to deliver this multidisciplinary design and build project.

“The new automatic and manualcontrol carriage wash plant was housed within a clad portal frame building. The scope also included full modernisation of the electrical and water distribution system to ensure recycling and sustainability were considered and achieved.

“The TrackPan system proved to be extremely versatile and provided a great surface within the wash to carry out any maintenance.

The team at Network Rail was impressed with the ease of

During the course of this project, Cairn Cross Civil Engineering was awarded the Star Lite Award for the standard of safety displayed throughout. This was presented to site manager Aaron Morgan who said: “It’s a great achievement for the project team to be awarded with the Star Lite Award. The acknowledgement of all the hard work that the project team has put in to ensure the highest levels of health and safety are met is fantastic”.

Cairn Cross Civil Engineering is delighted to have handed over the UK’s most advanced carriage wash facility to Network Rail and Arriva Trains. Innovation and value engineering are imperative to providing the client with the best possible solution.