I had the chance to pick up what I think is an earlier version of this rather common engine; 4 piece metal body (stamped "10 48" inside), "fancier" valve gear, separate handrails on boiler, back of cab and holding pilot in place...all very similar to my (2) 300 steamers.
Of course it didn't run; turns out the large gear that runs the "choo choo" plunger was seized; once I got that free (and cleaned everything) it bench runs fine...
I have now turned my attention to the tender; on this model (and unlike the 300) this has the reverse mechanism in the tender. Once cleaned, it seems to sequence okay, but does not work with the engine attached; will have to see if the wires connecting the two are okay.
Once again, I find these old pieces to be pretty much indestructible...and loads of fun to work on!
Mark in Oregon