Posts Tagged ‘21c11’

Two major steps forward for the General Steam Navigation Locomotive Restoration Society (GSNLRS), that aims to restore the Merchant Navy locomotive 21c11 / 35011 to her original as built condition complete with air smooth casing and Bulleid’s unique chain driven valve gear, were announced at last weeks Annual General Meeting.
Regular readers of my blog will know that I am a Trustee of the Society and Board member of the locomotive owning Community Interest Company.

Firstly, following the removal of the trailing truck from the frames in October 2020 and months of preparatory work by their hard working volunteers, that the restoration contract for the trailing truck has been awarded after a tender process to North Norfolk Railway Engineering.

The unique in preservation fabricated trailing truck

Located at Weybourne Engineering works, North Norfolk Railway Engineering presented a strong bid for the work, with a high level of engineering detail, that respects the historical merit of the unique in preservation fabricated Merchant Navy trailing truck.
Originally fitted to a series 3 Merchant Navy, 35011’s fabricated trailing truck is the last survivor of its kind. Lighter than the cast truck fitted to the other preserved Merchant Navy locomotives, longer than a Light Pacific’s truck, the GSNLRS are having this unique piece of Bulleid locomotive design restored to mainline standard, a crucial step towards GSNLRS’s vision of an original Merchant Navy with original air smoothed casing and Bulleid’s patented chain driven valve gear.

Funding for the Trailing Truck restoration has been via the GSNLRS Trailing Truck Transformers Fund Club and ‘Lots’ being available for purchase to join the club. Membership of our Trailing Truck Transformer Fund Club is still available, for details click here.

The second announcement is with respect to the crank axle,

Since 1966, 35011 has been without it’s central crank axle as it was swapped with a plain axle following withdrawal for the crank axle to be used on classmate 35026. Alongside the missing valve gear, this has been the driving force behind the decision to return to original design condition, due to the cost of replacement to either design being similar.

The FEA on the original Crank Axle design shows failure as per the failure on 35020 in 1953.

FEA of the balanced crank axle design as fitted to 35011 in 1954 with grade A4T steel showing no failure.

After many years of behind-the-scenes research in the Bulleid Pacific Locomotive Association collection & National Archive in Kew, and recent detailed Finite Element Analysis conducted at the University of Birmingham, under the supervision of Professor Karl Dearn, has demonstrated that A4T steel is of a suitable grade for the correct balanced crank axle design for 35011 in original design condition.
This means the GSNLRS can proceed to final design of the central axle & balancing of the motion, and the order placement for the steel in the coming months and moving the project further forwards to a functioning original Merchant Navy once more.
More information on the University of Birmingham FEA Project can be read here.

These two announcements are major steps forward for the General Steam Navigation Restoration Society, for more information on how you can help support  the project click

 

 

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