Was this built from a Walthers kit? I built one in my teen years (early 70's) including interior. However, the floor metal was so soft it didn't last until the present day, it bowed at the platform end and nothing I did helped it to stay straight. With great reluctance, I had to junk it.
Yes-sir it is an old Walthers kits, complete with interior. I now have collected 4 of these old kits, along with one from the latest run. Sorry yours had to go away. These old kits are getting hard to find and a bit pricey.