Physical Danger
Okay, we were kidding about that whole train mutiny business; there's almost no chance the crew will throw you overboard. Almost.
As a railroad conductor who primarily rides passenger trains, and doesn't actually do any of the hands-on dealing with problems, you'll be pretty safe—trains very rarely derail (seriously, it's pretty much the safest way to travel aside from a flying air bubble).
The more dangerous train-related work is as a freight conductor. You'll most likely have to do some of the physical labor that's mostly associated with freight crews and yardmasters. You'll spend time loading and unloading heavy materials from a freight train, uncoupling cars by hand, and a whole lot more tasks that really work the arms and back.
These are the situations that can get you a one-way ticket to the emergency room.
For the most part though, you'll be riding in a cushy seat and watching the mountains fly past your face on a passenger train. Enjoy the breeze, and watch out for bugs.