It looks like a Walthers Chicago, North Shore, & Milwaukee coach kit that has seen some rough service. They can be built up into almost brass-rivalling cars with a lot of effort. BTW, my 1948 Walthers catalog shows that kit so it has been available for a long time.
EDIT: Pittman/Bowser offered (Bowser may still) offered a vertical-motored drive (both two & three-rail) for their Brill semiconvertable that would work in this application although the trucks would be wrong for NS car. Note that salvaging a drive from an MTH or Lionel (depending on what control system you use) car is another option.
