I've always enjoyed watching trains, riding trains, building model railroads. I can see the orderliness of it all being appealing. As far as traveling goes, it's very comforting to be un-able to attend to anything else until I reach my destination -- and when I get there is out of my hands, once I'm on the train I don't have to worry about anything until I get to my stop.

This worked great for me until I lived in NYC, where the 4/5 express might become the 2/3 express en route to manhattan. Really have to stay on your toes as often as they cancel whole routes.