The predicable, routine ride on the subway seems to breed a population of people who, seemingly, can get on the train, sit down, fall asleep, and wake at the right stop. Training? Not really sleeping? Incredible time sense? There are all kinds of theories, and this article from the New York Magazine looks at some, with my input on some medical thoughts.
And this is not just a United States phenomenon, as the UK Metro site picked up the story and ran an abridged version: