Covered freight car, model 11-270. USSR, 1986. Widely used in Russia.
Two variants of underbody: one with fixed couplers for stand model, other with pockets for Kadee coupler (taken from https://www.thingiverse.com/thing:3099785).
Resolution: 0.1, infill: 5%. This is settings I've used to print main "vertical" part.
Disclaimer: I did not print wagon in "horizontal" mode, because my printer needs repair. If You found this details unprintable, write me and I'll try to fix it.