While not an all encompassing collection by any means - I do have numerous pics that I’ve shot of real equipment. Sometimes even up close for details. They come in handy for modelers… like myself… and others.
Things like the insides of empty woodchip cars. The tops of loaded coalporters. Brake end detail of covered hoppers. Coupler closeups for painting ideas.
http://www.mellowmike.com/prototypes.html
Additionally… I have shot various old brick buildings around where I live. I’m not the only guy who has these kind of buildings locally, I’m sure, but not many would drag a good camera to these neighborhoods and shoot photos! These are good for showing how older DPM-style structures vary in color. Not all brick buildings are red-brown with white mortar lines and green window frames!
http://www.mellowmike.com/Buildings/Thumbnails_19.html
The images are fairly big (1.0mb to 2.5mb) but you can see thumbnails without opening each one. It’s a private website - so there are no cookies or spyware.