10 minute read
Finishing off the fourth track between Bedford and Kettering
Apart from the electrification of the section of route from London St. Pancras to Bedford in the late 1970s, the Midland main line has had few upgrades of any significance throughout its existence, until the current major MML Upgrade which is now well underway.
MARK PHILLIPS
A major part of the MML Upgrade is the extension of electrification of the route further north. This has been something of a stop-go policy, inasmuch as plans to electrify the line as far as Sheffield were ‘paused’ by the government in 2015 amid concerns over the escalating costs and programme on the Great Western main line electrification scheme. After re-evaluation of electrification investment generally, the MML Upgrade was reauthorised in 2017 and included electrifiation as far as Corby - it is now in full swing.
Once the electrification and capacity upgrade of the Midland main line is complete, it will have seen the installation of 23km of new track, improvements at stations, including lengthening several platforms by up to 58 metres, and significant work to around 49 structures, including the reconstruction of more than 25 bridges. This means that, in late 2020, improved services will run between Corby, Kettering and London, with up to 50 per cent more seats during peak times between Corby and Bedford.
Electrification from Bedford to Kettering, and of the branch to Corby, is due for completion by late 2020. In March, the Department for Transport confirmed that it had instructed Network Rail to design a 15-kilometre extension of this electrification to Market Harborough, as this is likely to be the most costeffective way of connecting to the nearby Braybrooke feeder station. A decision on the construction of this extension awaits a full business-case assessment.
In addition to the electrification itself, the Upgrade includes route capacity improvements, speed increases, station enhancements at Bedford, Wellingborough, Kettering, Corby and Market Harborough and the removal of bottlenecks. Additionally, the signalling between Bedford and Kettering is being upgraded to an axle-counter system. One major contributor to the route capacity has been the provision of a fourth track between Kettering and Sharnbrook Junction, a few miles north of Bedford. Completion of this fourth track was the primary objective of a major route closure for nine days over the recent Christmas and New Year period.
An extra track
Passengers were advised, through major publicity by Network Rail and East Midlands Railway, that the route would be closed from the night of Christmas Eve until the morning of Thursday 2 January, with rail replacement bus services between Bedford and Market Harborough and Corby. The existing track layout between Kettering and Sharnbrook Junction consisted of Up and Down Fast lines and a ‘Down Slow’ line, which is actually signalled so that it can be used for reversible working when needed. The new fourth track being provided between approximately the 70 and 56 mileposts is designated as the ‘Up Slow’ and is signalled for use in that direction only. The original three lines retain their existing operating characteristics.
Apart from the normal requirement to raise or modify bridges and other structures to provide the capacity for the fourth line and clearance for the overhead wires, an additional feature has been the need to reposition several signals. These were mainly signals which controlled the existing Down Slow line but whose signal posts or gantry supports were obstructing the part of the formation physically needed for the fourth track. New gantries were required at these locations to accommodate the disrupted signal heads. Where possible, the new signals for the new fourth track were incorporated into these new gantries, although some additional stand-alone signal posts were required.
Sharnbrook tunnel, where the Slow lines diverge from the Fast.
At Wellingborough station, a fourth platform is being constructed which will later serve the additional line. New point and crossing work to allow access to and egress from the fourth track has been installed at Kettering and Sharnbrook Junction and modifications made to Wellingborough North, Wellingborough South and Harrowden junctions.
Preparatory works
The majority of the works described in the previous section were completed over many possessions and major closures over a period of more than two years. The scheme has been spread over a considerable period of time, doing as much work as possible well in advance of this particular closure, to avoid further disruption to passengers. For example, around Wellingborough North junction, a significant intervention was carried out in the Christmas 2018 closure to prepare that layout for the new facilities. During summer 2019, much of the work for the fourth track was put in place.
Even in the few days prior to the full Christmas 2019 closure, there were significant works by day and night towards completion of the fourth track. From 22:00 on Saturday 21 December until 22:00 on Christmas Eve, a possession of the Slow lines between Sharnbrook Junction and Wellingborough North Junction enabled significant platform construction work for Platforms 3 and 4 at Wellingborough. The new section of four-line track.
Nine days of Christmas
The main overall task for the 2019 Christmas/New Year closure was to complete the final elements, enabling the fourth track to become operational. These included the removal of the obstructing signal structures, so that the final few short sections of the fourth track permanent way could be installed at these locations and signalling testing and commissioning completed throughout. The major closure gave the opportunity to carry out much other work, such as the completion of associated overhead wiring and major construction and finishing of platform works at Wellingborough and Kettering stations.
Amey, framework contractors, did the work for the fourth track and associated switch and crossing work, the signalling work was by Siemens, overhead line work by SPL Powerlines UK and the stations work at Kettering and Wellingborough was also the responsibility of Amey.
The possession for the core nine-day closure was from 22:00 on Christmas Eve to 08:00 on Thursday 2 January between Bedford and Market Harborough. A critical part of the nine-day programme of works was to be the testing and commissioning of all the signalling over the whole section of affected route, which involves two new Siemens Westlock CBI interlockings between Bedford and Kettering. The last five days of the closure had effectively been allocated to this work and, for this, wheels free testing had to be available. Therefore, all permanent way installation, renewal, welding, stressing and tamping work had to be complete by Saturday 28 December.
So, the first four days of the closure saw intensive permanent way works: » Installation of closure rails, welding and stressing at 922 and 1570 pts and at Templers Way; » The completion of the infill track sections after the signal structure removals of LR100 at Harrowden Junction (180 metres) and of LR101/102 gantry at Burton Latimer (245 metres); » Track renewal between Wellingborough North junction and Smiths Sidings; » 1,500 metres of parallel tamping of the Fast lines through Wellingborough North junction; » Buffer-stop removal and headshunt installation at Neilsons Sidings; » Final welding and 2,010 metres of tamping at other sites on the Up Slow. For the electrification works, a few short sections of catenary and contact wires and fixings on one overbridge were completed, followed by registration and testing throughout.
The new section of four-line track.
The signalling works comprised, firstly, the removal of redundant location cases and the retrieval and removal of signal gantries along with the provision of foundations and erection of new signal structures. As the permanent way works were completed, wheels free testing was then sequentially carried out in six main stages over several days in the latter part of the route closure and the new signalling commissioned.
Another major activity, which continued without hindrance from other disciplines throughout the whole nine days, was the civil engineering works, mainly at the stations. However, so as not to compromise the wheels-free regime needed for the signalling testing in progress after 28 December, it was necessary to be able to transport spoil and materials across the tracks at the two stations. This was achieved by the use of poly-bridging.
At Kettering station, there were civils and drainage works for Platform 1, installation of precast tactile units and coping stones on Platform 2 and drainage and lighting column base construction on Platform 4.
Signal gantry LR60/64 had been a programme constraint at Kettering. The position of the gantry clashed with the footprint of the extensions to Platforms 1 and 2. Before the main nine-day closure, it had been possible to complete only 60 per cent of the platform extension works. Siemens commissioned the new gantry for signals LR60/64 at Christmas, enabling the removal of the old gantry and thus the completion of the remaining platform extension civils works. LR60/64 was removed by specialist demolition contractor Sammy Evans. Temporary decking across the Slow lines provided a surface for a 35-tonne civils excavator with a demolition shears attachment to dismantle the gantry in three parts.
Paul Kerrigan, stations project manager for Amey, emphasised to Rail Engineer two key elements for the success and efficiency of the work at Kettering. These were early engagement with East Midlands Railway in gaining permission to use the north station car park as a construction depot throughout the works to manage materials and spoil and the input from the civils contractor, BCM Construction, and its labour supplied by Crewit Resourcing.
At Wellingborough station, there were various civils, coping stone, drainage and duct-run works for the existing Platforms 1, 2 and 3 and completion of the construction of the new Platform 4. This comprised significant infill and compaction. On Platform 2, 160 metres of coping stones were refitted to an adjusted track alignment and 128 metres of copers were positioned on the Platform 3 extension. Also, Platforms 2 and 3 were resurfaced and anti-climb works to OLE structures carried out.
The possession was handed back early, at 05:46 on the morning of 2 January. The designed line speed for the new fourth track, the Up Slow line, varies up to a maximum of 90mph. When entered into use, the line will not immediately operate at that speed. It will be some time before the track is fully consolidated under traffic because there is no planned timetabled use of it until December 2020, when the electrified service will be introduced. Resourcing
The pattern of working was mostly overlapping shifts of 10 hours for most staff in order to keep 24-hour working going throughout the whole closure period. For some specific situations and activities, 12-hour shifts were rostered. 9,444 manhours were worked on permanent way activities, 13,200 manhours on signalling installation, testing and commissioning and 14,788 manhours on the civils construction work at Kettering and Wellingborough stations. Jorge Roque, Network Rail’s programme manager for rail systems and route clearance, said that there had been an excellent safety record throughout the Christmas closure, with not a single incident or personnel accident. At times, the Slow and Fast lines diverge.
At times, the Slow and Fast lines diverge.
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