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Vol. 234No. 4760 10 –23January 2025
124SMOKE RINGS
News,views andcomment on theworld of modelengineering.
128 ATANDEMCOMPOUNDMILL ENGINE
DavidThomasrevisitsArnoldThrop’s design of aCorlissmill engine
132 AUSTRIA’SZILLERTALBAHN
RogerBackhouse goes all theway to Austria fora ride on anarrowgauge railway
137 FLYING SCOTSMAN IN 5INCHGAUGE
PeterSeymour-Howellbuildsa highly detailedA3locomotivebased on Don Young’sdrawings.
142 WORKINGONTHE LATHE: DRILLING ANDBORING
Neil Raineexplainsthe artofforming holes usingthe lathe.
145 BOOK REVIEW
Paul Carpenterreads all aboutthe Far Tottering andOysterCreek Railway
146 ARADIALMARINE STEAMENGINE
IanCouchmanbuildsa triple expanson marine engine with thecylinders arranged radially
152 THESTATIONARY STEAMENGINE
RonFitzgerald tells thestory of the developmentofthe stationary steamengine.
154 IMLEC2025
Howard Atkins invitesentries forthisyear’s efficiency competitionfor 5and 3½ inch gaugelocomotives
156 ANNOUNCING LITTLELEC 2025
Adrian Newson invitesentries forthisyears efficiency competitionfor small locomotives.
157 NARROWGAUGE LOCOMOTIVE EFFICIENCY COMPETITION
Glyn Davies invitesentries from owners of locomotivesbased on narrow gauge prototypes
Mr Harding’sPerkins ‘hit andmiss’ engine seen at theLowestoft ModelEngineering Exhibition (photo:Julie Williams).
Bradford Cup
TheBradfordCup is awarded to theauthorofthe best article or series,bypopular vote, publishedin ModelEngineer during thepreviousyear. Last year’s winnerwas RonFitzgerald, forhis series on thestationary steamengine, whowas presentedwiththe cup at theMidlandsModel EngineeringExhibitionlast October, by Mike Chrisp, presidentofthe Society of Modeland Experimental Engineers.
MARTIN EVANS Editor
DIANE CARNEY Assistant Editor
Mar tin Evans can be contacted on the mobile number or email belowand would be delighted to receive your contributions, in the form of items of correspondence, comment or ar ticles. 07710-192953 MEeditor@mortons.co.uk
Theorganisersagain invite nominationsfor theaward of thetrophy, to be submittedto theeditorof ModelEngineer by theend of March2025, whichshouldrelatetoarticles publishedin ModelEngineer during theyear2024. Readers will then be invitedtovote forone of thetop three nominations. Submissions should includethe following:
*The author’s name;
*The titleofthe articleor series;
*The issuenumberinwhich it starts;
*Contact details forthe person nominating the article.
Youmay not, of course, nominate your ownwork!
TheJoy ofLECs
Nowisthe time forconsidering thepossibilityofpitting your wits,and your locomotive, againstyourfellowmodel engineers. Thecomingyear offers aseriesoflocomotive efficiencycompetitionsfor virtually anysizeand shapeof locomotive.These events are always very exciting andlots of funsoI wouldrecommend goingalong,evenifonlyjustto watchproceedings.
Theoriginal, andperhaps biggest,event is IMLEC (International Model Locomotive Efficiency Competition),founded
nearly60years agobymy distinguishedpredecessorand namesake Martin Evans(MkI) This competioncovers5 and 3½ inch gaugelocomotives andisbeing held this year at theFareham club.Details areonpage154.For smaller locomotives(5and 3½ inch gauge, under50lb) thereis LittleLEC at theTivertonclub. Details areonpage156.For narrowgauge andindustrial locomotives(again, 5or3½ inch gauge) thereisNGLEC, to be held this year at the Oswestry club,for whichdetails aregiven on age157.
Garden Rail Show
Plansare ‘ontrack’for the2025 Midlands Garden Rail Show taking placeonSaturdayMarch 1stand Sunday March2nd at theWarwickshireEvent Centre This show is oneofthe leading modelrailway events dedicated to garden rail. Theevent features the‘larger’gauges of OGauge,G Scale, Gauge1, 16mm andmore.
Therewill be over 15 layouts andclubs at theevent -plenty of inspirationifyou are planning your owngarden railway,whether it’s livesteam, gasorcoalfired.
Over 30 leadingsuppliers will also be at theshowtohelp youcreateyourdream garden railway,sellingeverything youcould need including locomotives, rollingstock,track andaccessories
Forfurther details on the exhibition andsuppliers attendingsee www. midlandsgardenrailshow.co.uk. Advancetickets areonsalenow!
Conundrum
John Arrowsmith from Hereford wondersifany reader
canhelpsolve this mystery –‘Iamattachinga photoof asafetyvalve whichisbeing fittedtoour newclubRomulus loco.Wehavea problemas to whyithas apluginthe bottomend of thevalve and holesaroundthe peripheryof themainbodywhich screws into theboiler. Cananyone enlighten us whythe plug is there? We have anumber of theories butnodefinitive answer -perhaps thereaders couldhelp.’
Theeditorial theory is that this arrangementmay help to minimise thechances of squirtinghot waterout of the safety valveofanover-full boilerbut Iamquite sure other theories areavailable.The editor will be pleasedtopass on anymorecredibletheories to John.
Cock-upCorner
Issue4757(November 29th)contained an account of thehighlightsfromthe Midlands ModelEngineering Exhibition.Photograph1 showed an excellent example of a7¼inchgauge BlackFive locomotive.Unfortunately the ownerwas wronglycredited. Theactualowner is Jeremy Dunn, to whom Iofferour apologies.
Garden Rail Show
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ATand em e m Compound Mill Engine
David Thomas builds Arnold Throp’smodel of aCorlissmillengine.
Continuedfromp.96
M.E.4759 December 27
The cylinderend cover (fg 29)castingswere pretty roughbut once centredaswellaspossible in thefour-jawchuck they were centre drilledtoallow tailstock support. That way, even if thechuck’s grip isn’t that secure,theycan’t work loose. In photo179 theouter surfaces andthe chucking spigot arebeing turned.With theturnedspigotgrippedina colletthe angewas broughtto thicknessand thecover turned to fit thebore photo180). Thecoversweredrilledfor thepistonrod andthe rear onecounterboredtogivethe
Then thebitsthatfitinsidethe bore were turned
Thechuckingpiece is left attached andisheldina V-blocksothata edge finder can be used to alignthe axis of thewiththatofthe mill spindle…
…and thefixing holescan be locatedwiththe DRO.
piston locknutsomewhere to go at therearwardend of the stroke (photo181). In thenext threepictures it s difficult to seebut thechuckingspigotis
still attached andisgripped by asmall V-blockinthe vice Thepartcan then be aligned with themill axis usinganedge finderand the R photo182), some clearancemilled forthe
steamtoget from theports into (and outof) thecylinder (photo183)and thestud holesand forcingscrew holes drilledusing theDRO hole spacingfeature (photo184). Before I’dmadeany of these bits Ithought that theforcing screwholes were only there
to be faithful to theoriginal engine;thisisn’t thecase andtheyare very necessary when,inevitably, thecylinder hastobedismantled. The final operations on thecovers were to counterborefor O-ring sealsfor thepistonrod glands (photo185)and drill andtap
Getting hold of thetop andbottomcoversfor machiningistrickywithonlya very rough1/8 inch
thestudholes forthese (no photo).The dummy metallic packings look very plainbut, apartfroma smalloiler, thereal things look just thesame. Thetop andbottomplates were more difficult to gethold of formachining.There was
plenty of metalinthe rough chucking spigots, whichwas fortunateasthese weren’twell centredonthe plateoronthe boss that wouldbecomethe pipe ange. hereloo edtobe twowaystogripthe casting in afour-jaw; by theedges or
by thepipe ange boss. he ‘least worst’ of thesewas to usethe boss afterithad been filed smooth er photo186). If Ialsocentredrilled the spigot andprovidedtailstock support,thenI forgot to take pictures or make notes- but it mightwellbeworth doing. Thechuckingspigotand undersideofthe platewere turned with this set-up and clamping waseasyfromthen on (photo187). In photo188 theoutside of theplate and pipe angehavebeen finished
Thesteam passage wasthenpilot drilled, butthe chucking spigot wasagain left intact
bump on onesidetogripinthe four-jaw chuck.
With aclean chucking spigot,holding thepiece to machinethe outersurfacesis easy.
…sothatitcould be used to alignthe part formillingthe edgessquareand drilling thesecuringholes
Theonlydifferences betweenthe topand bottomcoversare thesizeofthe steampassagesand thepitch circle diameter of the flangestudholes
andthe hole drilledpartway through, farenoughthatwhen thespigotiscut away andthe platebrought to thicknessthen it will penetratefully.For now, thespigotiskeptand clamped in a -bloc to finishthe outer edges(photo189). Cutting away thespigotand milling theparttofinished thic ness revealsthe hole,nicelycentred in the ange andthe plate (photo190). Thecorners were filed by hand to fit thecurved cornersofthe steamspaces andanother 40 holesdrilled, 16 of them tappedwith8BA threads(photo191). Figure 30 is across sectionviewfrom theCAD modelshowing the progress so far.
With thecover plates finished that is theend of thecastironmachining and time to give themachinesa thorough cleaning andoiling. My everyday workshop routine starts with abit of aclean-up butnow is thetimetoget rid of thegreydustproperly. Cast iron is my favouritematerial formachining butwithout the workshop vacuum (Karcher), cleaning themachineswould be difficult
To be continued
Drillingthrough released thechuckingspigotand thepartwas broughttofinished thickness.
Fig 30
An Engineer’s Day Out
Aus tria’s Zi ller talbah n Aust ria
Roger Backhouse recalls a holiday to theAustrian Tirol.
Despite beinghomelovin’ types, Mr.and Mrs. Backhouseventured abroad once again, this time to Austria’sTirol on aGreat Railway Journeys holiday.A trip on theZillertalbahn (ZB) from JenbachtoMayrhofen wasa highlight (photo1).
History
TheZillertalbahn opened in stages from 1900-1902 along32km(20 miles) of the ZillerValleyfromJenbach to Mayrhofen. It wasbuilt to 760mmgauge (2 foot 6inch),a gaugethe militaryrequiredfor minornon-electrifiedrailways in theformerAustro-Hungarian empire.Railwaysbuilt to thesamegauge included theBelgradetoDubrovnilk line, completedlater by the YugoslavianGovernment. Sadly, many minorrailways were closed In the1950s and60s with privatelyowned railwaysgenerally surviving betterthantheir state-owned counterparts
This 760mmgauge wasthe same as that of theWelshpool andLlanfairLight Railway opened in 1903, something that ledtouseful, collaborative workingyears later.
Therailway today
Unlikesomenarrowgauge railways, theZBisa yearroundcommercialoperation ownedbythe Zillertaller VerkehrsbetriebAGwhich also runs buses. TheZBterminus at Jenbachadjoins the Austrian StateRailways(OBB) stationand also that of the Achenseebahnrackrailway Thosewho remember run down Welshnarrowgauge railwaysinthe 1950sand 60s will findthe aremar able blendofexcellent track,
modern signalling, comfortable coachesand yetretaining fascinatingtraditional trains
Thejourney
Steamtrainswithheritagefour wheel coachrollingstock runa return journeyfromJenbach to Mayrhofenthree days aweek during thesummer. Much of thesingletrack routefollows roadsthrough thevalley, though nota roadside tramway (photo2). It is ascenicrun but, unfortunately, thevalleyis marredbyribbondevelopment alongthe main road On ourjourney the
With open balconyrolling stock, passengerssmell the smoke. By riding in thefront balconytheyare closetothe locomotive;a greatexperience much enjoyedevenbythose whoare notnatural steam enthusiasts(photo3). At Mayrhofenthe engine took waterwhile thecrew hada break, before running roundthe traintoreturnto Mayrhofen(photo4). On this tour ourreturnjourney wasmadebydieselrailcar offering an excellent ride using
Compound locomotive No.3, Tirol at Jenbachstation.Thishauls many heritage steamtrainsduringthe summermonths.
Tourists’viewofthe Zillertal from theHeritageTrain
modern rolling stockand on well maintained track. Thereis continuous welded rail almost throughout.The linehas dedicatedtrack maintenance vehicles (photo5). As an Alpine railway it hassnowploughs, although newsnowclearing equipmentisexpectedtobe introduced (photo6).
Thereislittlemajor civil engineeringapart from girder bridgesatRotholz andZell am Ziller. Locomotive sheds andworkshops at Jenbach arecomparatively modern andstation buildings are substantially built (photo7).
Signallingiscolourlight andlocomotives arefitted with balises so trainlocation is knownprecisely (photo8). Thanks to electronic signalling systemsthere arenophysical tokenexchanges forsingleline track.
Goodstraffic
When opened,the Zillertalbahn hadtransporter wagons to take standard gauge wagons andretains these vehicles (photo9). There wasmagnesite (magnesium carbonate traffic from anow closed mine near Mayrhofen. ome timber traffic goes to a localfactory usingtransporter wagons (photo10). These vehicles have long connectors between them to avoid problems with theoverhangon standard gaugevehicles.
Steamlocomotives
Austria’sminor railwayswere less li elytobeelectrified than thoseinSwitzerland and
9 10 generally retained steaminto the1970s.Locomotives were mostly builtbetween 1888 and1930byLokomotive-
5 7 6 8 3 4 Standard
Fabrik Krauss of Linz andthe Weiner Lokomotive-FabrikAG Floridsdorf, Wien Two0-6-2 Uclass tank
engineswerebuilt at Linz forthe line’sopening.No. 1, Raimund is displayedona plinth in Jenbachand No.2
View into No.3 cabfromthe balcony coachbehind. Almost as good as acab ride!
Ballast wagons contribute to thehighstandardoftrack on the Zillertalbahn
Stations likeSchlitters Bruckare well built andmaintained.
Balises likethisare fittedtolocomotives to enable exact locationstobeknown
No.3 takeswater at Mayrhofenbeforethe return journeyto Jenbach.
Snowplough -thiswill be replaced with more up to date equipmentshortly
operated on theWelshpool andLlanfairRailway butwill return to Austriain2025. These were followed by No.3,a Uv classcompoundbuilt in 1902 by Krauss whichhauls most steamservices(photo11). No.4 Is ownedbya group of enthusiasts(photo12). The engine is a0-8-2 with small side tanksand afour-wheel tender built formilitaryuse by Krauss in 1909. It worked in
Like otherlocomotives, thevalve gear is described as Heusingervon Waldegg. Although some claimmajor differences between thetwo valvegears,toa non-expert it lookssimilar to Walschaerts andwas independently
invented around thesametime. Heusingertakes less space andismoresuitablefor tank locomotives.
t is fittedwitha spar arrestingchimney.Austrian coal wasnot good quality andsometimes briquettes were used andevenwood fuel.Duringmyvisit engines used Welshsteam coal but that source hasclosed. Locomotivesare fittedwith
ocomotiveshavesubstantial boilermounted sandboxesand turbogeneratorsasseen on No.3
substantialsteam turbine electric generators andlarge lights(photo14).
Linsomecases,the locomotivesshowed innovation:No. 5, Gerlos was also an 0-6-2tankengine built by Krauss at Linz that used Caprotti valvegear, but this wasreplacedin1941 with Lentzvalve gear.The locomotive is nownamed Castle Caereinion butis currently outofservice awaiting newboilertubes (picture15).
TheZBacquiredlocomotives andcoaches from other railwaysIncluding the Salzkammergut-Lokalbahn (SKGLB)which closed in 1957. Probably thelargest ZB engine wasthe ex SKGLB 0-10-0 tender tank engine built by Borsig in 1939but whichis nowelsewhere
No.5, Gerlos on traintoMayrhofen with classicmotor transportalongside.(Photo courtesyGûnterDenothand ZB 2024.)
No.4 on shed at Jenbach. It is ownedbya groupof enthusiasts andnot theZB.
Cabpicture No.3 -notethe weight on thecut offlever
0-8-2tankand tender engine No.4 with train. (Photo courtesy Gûnter Denoth and ZB2024.)
ThreeLupoclass diesel hydrauliclocomotives likethisoperate most passenger trainsand freight. Thedecorationadvertisesa touristattraction near Mayrhofen.
Zillertalbahn
Amoremodern, open carriagegives asuperbrideona fineday
Demonstration of howa rack locomotive worksatJenbach.The Achenseebahnusesthe Riggenbach system with aladderlikerackinthe centreofthe track.
usinga lightweight chartertrain with an 0-4-0tankenginebuilt by rauss in unofficialiy knownas DerHobbyzug (photo16).
Diesels
Most work is nowcarried out by diesels. Three‘Lupo’class diesel hydrauliclocomotives operatefreight trains and also many passenger trains in apush-pull set-up with railcars. BuiltbyGLG Gmeinder MosbachwithCAT 3412 engines, they were introduced in 2007. At thetimeofour visit, thelocomotives hadvinyl decals advertising Mountopolis, atourist attraction near Mayrhofen(photo17).
D40
at Jenbachfor repairs. It was built in the1940sand used on theSKGLB.Itisnow operated by thevoluntary (Club760) Taurachbahnheritagerailway near Salzburg (photo18). Thereisalsoa small locomotive (D1) built in SwitzerlandbyDiema used for yard andworkshopshunting.
Coaching stock andrailcars.
hard wooden seats(photo 20). Some coaches have been convertedtoa children’s carriageand abuffetcar.Many Austriansenjoy leisurecycling andthere is abicycle carriage to accommodate those; indeed theZBhas acycle hire service
Most passenger services areoperatedbymodernbogie coaches. Although notas picturesqueasthe olderstock, they offera remarkably smooth ride.Atleast oneisfully open, idealfor warm sunny days (photo21).
Workshop
Thanks to avisit arranged by Gûnter Denoth,I visitedthe running shed andlocomotive workshop though thecarriage workshop wasnot visited. The workshop is well equipped with machinetools includinga largeradialdrill, awheel lathe obtained from SNCF (photo22) andanhydraulic press. Iwas told that theworkshopcan make anypartfor asteam locomotive although boiler repairsare carried outbya nearby company. TheZBalso does work forother Austrian narrowgauge railways.
TheAchenseebahn
Unfortunately, it wasn’t possibletotravelonthislovely railway to theAchenseethis holiday.Itopenedin1889 usingthe Riggenbachrack system with three0-4-0 tank locomotives, twoofwhich are still in operation. It is 7kmlong with gradientsofupto1 in 5 (photo23). 17 19 20 18 21 22 23
This diesel is believed to be unique andduringmyvisit was
TheZBretains original four wheel wooden coaches forheritagesteam trains (photo19). With endbalconies they arepopular with passengersdespite having
Olderwooden four wheel
coachesusedonthe heritage train. Endbalconies arepopular with passengers.
Interior of thefourwheel coacheswiththeir wooden seats.
Locomotive D40was built in the1940s andusedonthe SKGLB. It is ownedbya groupofenthusiasts
Zillertalbahn No.2,ZillertaldescendsfromSylfaen towardsCastleCaereinionon the Welshpool andLlanfairLight Railway.(PhotocourtesyofAndrewCharman 2024.)
TheZillertalbahn in
Wales
TheWelshpool andLlanfair LightRailway andZillertalbahn have enjoyedgood links and it’s thanks to this relationship that theWelshpool andLlanfair LightRailway received three
Austria holiday
ex-Zillertalbahn andone exSKGLBfourwheel coaches in 1968.Theywerepressedinto servicealmostimmediately, such wasthe shortage of coaching stock. These distinctivecoaches have been
This was aGreat Rail Journeys tourled by Julia Hartke. Although ageneral interest holiday GRJ generally use rail travel toEurope supplemented by coach excursions. Ffestiniog Travel offer Austrian holidays aimed more at rail enthusiasts.
Further reading
Adrian Garner visited several minor Austrian railways in the 1960s. His excellent black and white photographs included pictures of the Zillertalbahn and Achensee lines published in:
•Tirol Transport Museum near Innsbruck (not visited) hasa fleetofheritage trams and other transport.Open on summer Saturdaysonly. www.tmb.at/en/museum
•The GRJ holiday included acoach excursion over the amazingly engineeredGrossglockner mountain road, aholiday highlight. www.grossglockner.at/en.The main line journey from St Johann to Zell am Zee is an attractive ride included in, as was Salzburg (with modern trolleybusesand Christian Doppler’s birthplace.His discovery of the Doppler effect gave riseto
restored andremainpopular TheZillertalbahn locomotive, No.2, Zillertal wasdelivered to Welshpool in August 2019 with W&Lstyle Grondana couplings alreadyfittedby before despatch anditwas immediatelymoved to Llanfair (photo24). Aftera full boiler examinationthe locomotive made itsfirstfullround trip test runlater that monthand it enteredpassenger traffic on thefirstday of theannual steamgala.
Following commissioning at Llanfair,the locomotive completed8800 milesonthe W&LuptoJune2024whenit waswithdrawn with afailed firebo stay. thas been agreed that thelocomotivewill return to Austriaata mutually convenient time.
AnotherAustrianlocomotive thereisNo. 10, SirDrefaldwyn. Thelocomotiveisan0-8-0 tank engine built in France by theSocieté Franco-Belge and suppliedtothe German Military Railwaysin1944.Itworkedon theSKGLB andthen in Styria before coming to theW &L in 1970.
Aftera substantialoverhaul, SirDrefaldwyn re-entered passenger traffic in une at the‘60 YearsofPreservation’ event. At theend of August this year that painting and lining-outwas fully completed. Despiteits size,thislocomotive hasa shorterwheelbase than TheEarl or Countess andhas an unusualarrangement for thefront axle allowing lateral movement on curves.
radar.) Mozart’s birthplacetoo andthe cathedral organ he played -the concerts areexcellent!
Thanks to Gûnter Denoth (Zillertalbahn)
Ron Fitzgerald (Bradford Model Engineers)
Richard Gibbon (York Model Engineers)
JuliaHartke (Tour Leader, GreatRail Journeys)
Bettina Klotz and Jacqueline Lechner (Achenseebahn)
Peter Thorpe(NRM Search Engine)
Bruce Webber and AndrewCharman (Welshpool &Llanfair Light Railway)
Further information
Great Rail Journeys www.greatrail.com 01904 734154
Zillertalbahn Verkehrsbetriebe AG
Austrasse 1 6200 Jenbach, Austria www.zillertalbahn.at
Achenseebahn
Austrasse 1 6200 Jenbach, Austria www.achenseebahn.at
Welshpool and Llanfair Light Railway www.wllr.org.uk LlanfairCaerenion, Powys. SY21 0SF Tel 01938 810441
GreatRailJourneys
Zillertalbahn
Achenseebahn
Welshpool and Llanfair LightRailway
Flying Scotsman in 5Inch Gauge Gaug
Peter SeymourHowell buildsa fne, fully detailedmodel of Gresley’siconic locomotive to Don Young’sdrawings.
Continuedfromp.88, M.E.4759, December 27
Withthe reverser dealt with it is nowtime to take alook at the reachrod,but before doingso, Idecided it wouldbewisetodo some checks on thereverser’s position,tomakesureitwas correct,asthe length of the reachrod is very dependenton wherethe reverser sits Ineeded to checka few things such as that theboiler wasinits correct position.To do this Ineeded to temporarily fit thecab andthe smo ebo to see, when added, howthe boilersat in relation to therear main drivers, theashpanand whetherthe smo ebo was sitting in itscorrect location
on thesaddle. Ifound that thecab wasverytight against themanifoldbushand at first thoughtabout moving the caba fraction forwardtogive room.Thisworked, andthe smo ebo couldstill be fitted in itscorrect position on the saddlebut Iwasn’thappy until Idiscoveredthatthe boiler wasbeing forced alittletoo far forwardtoclear thereverser, requiringmetomovethe caba little. Everything fittedli ethis butitwasn’tright andI knew that it wouldalwaysbug me, even if it wasn’t somethingthat anyone waslikelytonotice; we were,after all, only talkinga fewmillimetres.
Therewas only onething to do andthatwas to move thereverserbacka few millimetres. My approach was to make adrillingjig from a scrappiece with theholes drilledtotapping size only and, with thejob still held in the machinevice, to drill theholes to drawingusing theDRO Before removing thepartfrom thevice drilledtwo e traholes afew millimetresforward of twodrilledholes alongone line, whichweredrilledtoclearance sizes. AllI hadtodothenwas drill throughthe jigand then tap thenew 6BAholes (photo1). Anothercheck done before doingthe abovewas to dry
fit themanifoldasitwas this part’s bush that wassitting abit closetothe spectacle plate(photo2). This is atrue scaleitem, as will be theother bac head fittingsonce getto machiningthem. Allofthese were kindly drawnbyAdamof CroFittingsand then cast in NewZealand by MichaelJack. They areall superb andwill enhancethe backhead beyond what couldbedonebyhand.
Here we seethe reverser nowinits newposition- much better(photo3). Nowthat Iwas happy with theboiler position Iplaceda mark on the boilertoma eiteasytofind it again(photo4).
On to thereach roditself. Thetwo main components
were lasercut formebyEd Parrott (Model Engineers Laser) many moonsago so most of theboringworkhas been done.I still need to make theforkonthe frontsection andthe sleevethatstrengthens thejoint.Following Don’s overalldimensions(he does say‘checktoplace’) Iclamped thetwo sections together.With thetwo partsclamped Idid aquick checkalongside the modelitself- it lookspretty much theretome(photo5).
Dry fit ofthe manifold to check clearance.
Test assembly of thetwo halves of thereach rod.
Tongue machined in thefront half of thereach rod.
Test fitting thefront endofthe reachrod
The reverser correctly locatedinthe cab.
Following Don’soverall dimensions,I cutthe front sectiontolength(both sections hadbeenlaser cutover-length at my request).I’llmakethe fronttodrawing andcheck the rear length in place- Ineed to be on theballhereasthere is no adjustment in thedesign. hefirst ob wastodrill the threeholes andthenmachine thestepdownfor thetongue, so farfollowing Don’sdrawing (photo6). Forthe tongue width Ichose asizeinbetween Don’s andthe worksdrawing -to make lifeeasierI chosea width to matcha suitable cutterto
10
hand making therequiredslot to therearsection easier.The photoshows that Ihavecut a2mm wide slot down the middleofthe tongue.IfI’d had my head properly engaged before machiningthisslotI wouldhavefirstadded the e trametal re uired to either side to representthe step as seen on thefull-size.Nobig deal butitmeant e trawor as needed to drill both e traside pieces before silver soldering them in place. Silver soldering wasdonebyholding theparts togetherwithtwo 6BAbolts/ nuts whichwerefirstheavily
coated in barsoaptostop them from becoming part of thepartduringheating,which worked perfectly. Here we see thefinished frontsection after beingcleaned andpolished (photo7).
Before moving on to therear section first test-fittedthe frontend to thelifting armas seen here (photo8). Alllooks good so farbut Iwill need to make the‘hoop’typebracket that’s attached to therunning boardmainstaythatthe rod runs through. Ialsorealised that needed to finishoff the lifting armas hadyet to fit its
11
taperpin.Using acoupleof clipsand checking that both thereverserand lifting arm were in ‘mid-gear’ Iclamped thetwo reachrod sections together.The reach-rod sections areliningupnicely (photo9). Photograph 10 showsthe twosectionslined up formarking wheretocut.
Nowit’stimetotacklethe rear sectionand thetwo pins re uired forfitting of thereach rod. There’sno‘fork’toworry aboutthistimeand onemight thinkthatthiswould mean a speedyconstructionfor the rear butwedohavethe the‘I’ beam type jointtoconstruct whichactuallyismorework than asimplefork.
Aftersetting up therear blankinthe machinevice andclockingthe centre Iset aboutmachining thesloton both sidestocreatethe ‘I’ beam required forthe front sectiontonguetoengagewith. Imarkedout thelengthofthe tongue andmachinedtothe line. In photo11 Iamchecking thetightness of thefitbetween the‘I’ beam andthe tongue Of course,I can’tfully engage
Clamping thetwo sections of thereach rodtocheck theft.
thetonguehereuntil Icut the corners which didfirstwitha suitable chisel followedupwith theDremeland asmall cutter. e t up were thebulgesseen topand bottomaroundthe joint on theprototype’s reachrod (photo12). Iapproached this by creating achannelina pieceof steel barthat first machined down to asizerequiredto matchthe full-size scaleand then cutintwo to give both topand bottomsections. The
channelwas cuttoa depththat when fittedwould also engage with thetongue, thewidth of thechannelmatchingthatof thereach roditself. In photo13 we seethe twosectionsready forbrazing to therod.Once fittedtheywerethenmachined to length
Once thebulge sections had been fitted couldshape them andpushthe tworod sections together anddrill throughthe threeholes.In photo14 we see
closer to scalesize, asimple jobfor long-nosepliers.I used asuitablysized PCB high-speed drill at more than 1000rpm to ensure aholethat stayed on trackand notdeviate from theplanned routeclose to the6BA nuts
theholes beingdrilled. Note that Ihavealready done some of theprofilingtothe bulge i.e. theconcave recess seen on the left-handside.
Photograph 15 showsthe generalshape of thejoint very closetoits final stage ust needinga final polish. he boltshavebeen fittedwith washersonbothsides and then cross-drilledtoaccept 1/32 inch split pins.I reshaped thepin headstomakethem
Onequestiontoansweris whether4472had apainted reachrod as shedoestoday, back in thelate1930s. She certainlydidn’tin1934 when shedid her100mphrun as we have thefamousphoto showingthe record-breaking crew standing in frontofthe unpaintedreach rod. I’ll seeifI canfind more pictures closer to to confirm my beliefthat therod remained unpaintedfor my era.
