Once, years ago ,I casually observed the Crescent n.b. leaving ATL. I was walking over a bridge adjacent to the station....just walking home from work...had not been at the station looking at the train. Anyway, a vestibule door was wide open, steps out, etc.. I sort of panicked, went to the nearest phone, tried to explain to somebody at reservations to see if they could "contact the train" but it was a lost cause.They had no idea what I was talking about. Guess nobody fell out or jumped, though. Seriously, a person casuallyopening the door, walking through the train could lose their bearings and literally fall out of the train, with the door wide open, steps down as it was. It could happen to ME because I have a dizziness problem at times. But even with that I am a lot healthier than a lot of other people on the train, point being that is a tremendous danger to any of us.