I've been wondering the same thing, though I've never found an answer. I wasn't planning on being fully loaded though. That is, my loaded bike shouldn't take up any more room than it would unloaded.

When you took your bike on that "short trip," did you leave your bike in one piece, take it's wheels off to make it compact, or go all of the way and put it in a luggage case? I went to Chicago via train last year, and I was wanting to take my bike with me this year.