Hopes for the Duke to return in 2021 with performance improvements
PROGRESScontinues tobemadeon No. 71000DukeofGloucester, which is currently under overhaul formain line serviceatTyseleyLocomotive Works ( TLW). It isnowhopedthat the Pacificwill returntotraffic nextyear, the Covid- 19lockdownhaving heldupthe projectsomewhat.
TrevorTuckley, chairmanofBRClass8 SteamLocomotiveTrust, told Heritage Railway:“Fingers crossed, wehopethe Duke willberunning during the second half of 2021.”
Asked about the latestdevelopments, Trevor said:“Thesupportcrewteam leadershave returnedtoTyseley andcreatedaCovid- 19safeworking documentandissuedit toallmembersof the supportcrew. Membersof the team atTLWhavecompletedtheweldingup of the drivingwheelbores, whichwere movedtoBoroFoundryatLye, near Stourbridge for re- boring.
“Thecannonboxeshavebeen completedatMetalockEngineering in CoventryandreturnedtoTyseleyfor the manganeselinerstobematchedand fitted. Thecannonboxessit betweenthe wheelstocarry the bearings.
“Thewheels returnedtoTyseleyon July 16 for final fettling. Along with the cannonboxes, they will soonbemoved toSouthDevonRailwayEngineering at Buckfastleigh toawait thearrivalof the tyresandstub axles fromSouth Africa. This willbefollowedby the reassemblyof the crank axle.”
As forotherprogress, Trevor said:“The ashpan is being rebuilt toensure thatall matingfaces areairtight including the hopperanddamperdoors. Thesurface machining of the centre cylinder is also in handso thatwhenthis isdoneandthe air pumprefitted, theboiler canbereturned to the frames.”
Upgrades
madebetweenMerchantNavyPacific No. 35028 ClanLine andtheDuke.
“TheDuke’s slidebar overhangat the front is10inches longer than ClanLine’s,” saidTrevor.“Four inches of thiswasto accommodate the longer piston stroke. Theadditional six incheswastofacilitate ringchanges as the pistonrodcouldbe uncoupledfromthecrosshead, thefront cylinder cover removed, andthe piston drawnforward while the slipperplate remainedin the slide bar, toenable the pistonrings tobechanged. Clearly, this is an advantage in termsof timerequiredto fitnewrings.
Cylinders
current overhaul. Anewdesignofpiston headandrodwouldbeintroduced. The existingarrangement consists ofarod, which is frictionwelded toapistonhead. Thismeansthatanywear of the piston headrequires it tobebuiltupwithweld andre- machined. This isnotconsidered tobeaverysatisfactory solutionas the weld produces an extremelyhardsurface which, ifbitsbreakaway, scoresthebore of thecylinder.
“Thenewassembly will have separate rodsandheads, which enables the use of differentmaterials for each. Therods willbesteel, whichwill have theirends threadedso thatcast ironheadscanbe securedwithanut. Thenewheadswill have three pistonrings. Anyfuturewear of the pistonheadswill only require theheads tobereplaced– amore satisfactoryandcost- effectivesolution.
“Thecylindershave allbeen re- bored, with the outside ones having additional lubricationprovided. Itwasnotpossible to carry out thelubrication modification to the centre cylinderdueto its location betweenthe frames. As the centre cylinder did not displayanything like the sameamountof ringwearasthetwo outside ones, itwasdecidedto accept this situation.
“Because the revised designofpiston rodandheadrequirenewfrontandrear cylinder covers, toaccommodate the extralength asaresult of the securing nut, itwasdecided to provide fixings to the rear covers which will enablethe slide barstobesecuredto the cylinders. This will provideadditional support to the slidebar bracket andremove any possibility of theslide bar flexing at its extremities.
“Webelievethat thesemodifications will improvethelife of the pistonrings alongwith the steamtightnessof the cylindersandhence the efficiencyof the Duke. Webelievethat themodifications wearemaking to theDuke during this current overhaul areprobably in line with the ones Riddleswouldhavemade hadhebeenallowedthetime to fine tunehimandachievehis objectiveof producingthe final, most advanced, efficient, powerful express steam locomotivetoever runonBR.”
Finally, Trevorsaidhewished to placeonrecordhis thanks to allwho continue to support theDuke.“Despite coronavirus, we’venowgot in excess of 400members– andincludingGift Aid, ourannualisedincomeis £ 84,500 perannum. Wearemostgrateful to ourmembersandsupporters for their ongoingdonationsandassistance.”
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