3-1/2" gauge and somewhere between 1-1/6" to 1-3/16" to the foot scale. It was built by Jim Vail (the model railroader) of Felton Ca, back in the '69-'75 time period.
I have yet to talk with Mr. Vail about this model he built and the NdeM engine he was patterning the model after. He never built a tender for it. He used to run it from a flat car with a fuel (Kerosene / Oil) tank and a water bottle with a hand pump. No running boards, no air pumps, no turbo generator, no bells no whistles.
I'm not going to have the time to work on the engine till next year, so I have plenty of time to plan and stockpile materials.
As of now the "plan" is:
- Build an NdeM style tender.
Remove the 2nd sand dome & replace with a bell.
Move the headlight to the top of the smokebox.
Add two 3/16" tube size injectors.
Build a Pyle-National E turbo generator for just in front of the cab.
Build two (cosmetic) Westinghouse 9-1/2" air pumps for just in front of the firemans side. of the cab.
New SPNG/N-C-O style cab of steel with a tighter rivet pitch.
Baldwin Builders plates, and new number board.
And the final touches will be "Southern Pacific Lines" on the tender and number "23" on the cab and number board.
Cheers,
Curtis F.