Strathclyder
Established Member
Rather academic now seeing as the engine is away for rebuilding/modifications, but I seem to remember that D5705 had a modifed Crossley HST-V8 installed during a extended stay at Crewe Works in 1967 (a redesigned crankcase comes to mind), which may have been one of the primary reasons it was selected by the Research Division at Derby to provide the motive power for it's Tribology test train and in turn the main reason it survived into preservation.
The YT channel Preserved Railway has a video (from January this year) of one of the volunteers at Bury giving a talk about the work currently being done on the engine and what still needs doing (timestamped video below):