Maurice P. has an interesting model on the stocks. Maurice has kindly written up some notes about the background to the model which, together with some photographs he has sent in to the Newsdesk. Earlier last year Maurice visited Almondell with his other locomotive for its steam test. This too is a variation on an LBSC design.
Main deviations from LBSC’s design are:
- Balanced slide valve above LP cylinder rather than unbalanced valve beside it.
- Smaller diameter boiler (LBSC’s size would have to be dented to fit between the driving wheels!).
- Smaller slide valves with reduced lap on the HP cylinders. (The Dockstader valve gear simulator is a wonderful thing – showed that the original setup meant the Joy valve gear slides being tilted through an excessive angle to get a decent cutoff for starting.)
- Didn’t bother with bypass valve and second superheater for steam going to LP cylinder. This was mostly to avoid having the small smokebox full of complicated pipework. (The smokebox of the original LNWR locos was bunged with pipes – must have been a nightmare to remove the trapped ash)
It’s bedded in well running on compressed air but might get scored like hell on steam – we’ll see!
HP cylinders, valves, pistons and rings are cast iron.
Decided to use metric stainless Allen and Torx screws to hold it together. M2 is the smallest size used.
Experience with e.g. the inside Stephenson valve gear on Petrolea has left me with a temporary aversion to extremely small nuts and bolts especially in confined spaces.
Hope you are keeping well. All the best, Maurice’