I'm no modeler but theoretically this should be a simple edit. Take the TF2 boxcar prop, slide the doors open and give it an empty interior. This way players can not only go on and around the prop, but through it. I'm kind of surprised that someone hasn't done this already but, if they have, please leave a link to it.
Ill take a swing at making this something like this: Btw theres a ton of good TF2 references to be found in model train sets since a lot of people like the goldrush environment
no one did it already? damn. anyway i made this prop because one requested and i have such large heart that i can't decline help. here the model https://tf2maps.net/downloads/boxcar-with-doubledoor.9675/
