[f2paul]

I don`t know the name for them but the 31 and Pullman all had a motor bogie with a worm each end of the armature that drove a cog directly on the axle. This was long before the ringfield "pancake" motor first showed up in the Class 47.

 

[f2paul]

Just dug out an old Hymek with same sort of motor , the bogie is cast metal so there`s going to be quite alot of work adopting it to take , say, a spud or black beatle. If it can be repaired try sticking with the original .They hum along nicely when in good feetle.