From the webcams at Skomish WA, the back half looks like a caboose end.
Henry
COB Potomac & Northern
Shenandoah Valley
I just had to check that! Word on street ( different forums) says it has a sister plow, 972504, that was built in Skykomish, by the GN in 1936.
RRpicturearchives has a few pictures of 972502.
Trainorders forums has some info, and pictures, but I'm not a member, and you need to be to look at a bigger picture.
Yes, the back does look caboose-ish.
Nice catch Henry.
Mike.
My You Tube
This appears to be a GN built 'Snow Dozer'...
Modeling BNSF and Milwaukee Road in SW Wisconsin
Virtural Railfan is calling it a Jordan Spreader