[shanac]

because of stopping. It takes more force to stop. Plus you would throw everyone and their stuff on the train around the process (they have no breaks for their forward acceleration).

You already feel a mild version of this in rush-hour on NYC subways. Your body will move slightly as the train breaks, often causing people to lose balance (particularly if they never experienced this previously)

[eli_gottlieb]

Thus leading to the well-known sport of Subway Surfing.

[vinceguidry]

Hah! I thought I was the only one who did that. So much fun.