Well, seeing as how often we travel (rarely), I havent been to too many parks, therefore, there isn't much contest. I live minutes from SFGAm, so I'd have to say the most comfortable trains are: Raging Bull and Whizzer. The American Eagle, being one of my favorite rides, ironically has probably one of the most uncomfortable trains, seeing as how narrow the train is, and how un-narrow my butt is..... And to the few parks I have traveled to (Kings Island (1), Indiana Beach (3), Disney World (1), I would say Space Mountain was rather comfortable....