New York City's subway is one of the few underground transit systems to stay open 24 hours. That's nice for bleary-eyed revelers and late-shift workers heading home. But it's difficult for the people who clean and repair the system between trains. NPR's Robert Smith spends the night on the subway that never sleeps.
Jeff Rogers, NPR
Musician Andrew Katz says he prefers to play guitar in the subway at night, when he's got the stage all to himself.