Depending on the railroad, there may be a historical society website with that kind of information, but you're more likely to find it in commercial publications (See Morning Sun books, for instance).on that railroad's passenger cars. There is not, so far as I know, an one stop shop for this information.
ONE site showing the evolution and history of EACH railroad?
Research each one independently.
There may be photo sites like rrpicturearchives.net and rr-fallenflags.org that can get you some "snapshot" reference points by the dates of photos, but otherwise you'll need someone familiar with the specific railroad to have anything documented about that railroad's schemes.