I believe the trains are still very crowded at rush hour. People get used to that because driving is not an option and it is socially acceptable for everyone to take the subway.
So you would sleep on an MTA train during rush hour with your bag just sitting on your lap? Most people I know wouldn't.
> Most New York trains are not really crowded at rush hour, with the exception of Lexington avenue line.
And neither are most lines in Tokyo. There are 2 or 3 trunk lines that are really crowded. The rest have only moderate occupancy. Each month, I was probably on a train where I didn't have room to move only once or twice a month.