Besides looking through RailImages, I recall a website with pictures of rolling stock sorted by railroad, car type, and maybe even number. Darned if I can find it now, but it seems like it would be perfect for photos to help my weathering look more realistic. Any help?
Both of those are excellent sites. Also, if you do Facebook, there are a few railcar groups on there that have a lot of pictures. Of course they are not indexed like the two previously mentioned sites.