It is unfortunate that graffiti paint obscures details that can provide clues.
It is a lightweight passenger car with stainless steel siding and a smooth roof, so it would have been built by Pullman or ACF rather than Budd. I see a vestibule and don't see a baggage door(s), so it is not a dining car or a baggage car; it could be a sleeper, coach or lounge. What I can see of the windows suggest a sleeper. I cant tell if I see two ventilation grills in the roofline, or if that is part of the graffiti paint. If those are actually ventilation grills, then that would suggest a bedroom lounge car with a small galley. I also see a long letterboard over the window line. Plenty of room for lettering something like Richmond, Fredericksburg & Potomac, or Seaboard Coast Line.
The car may have been jacked and the trucks removed for a rebuild, or used on another car. It does have that forlorn abandoned in place look to it.
Was this the shop of the defunct Atlanta era dinner train that operated in the 1990s ?