Out of curiosity I tried to find some information about it, but came up short. The view on Google Maps from June 2009 shows the train car in a much different state - completely intact with no graffiti (although it is from quite a distance). It makes me think this must have been a cabin. Someone clearly had something in mind when the train tracks were removed from the area.
The interior is now completely burnt out, and various styles of graffiti cover most of the exterior. It was actually a bit eerie, because the area was completely quiet. No other cars on the highway, and no direct path for even getting to the train car - I just walked across a field. That could be a good reason why it's abandoned.