The New York City subway is so many things. Sometimes it is on time, even fast, but other times it’s slow, mired in interruptions and delays. Occasionally the ride is smooth, but often it jostles and rumbles noisily. It passes through much of  the city, and its passengers include commuters, as well as buskers; and the homeless. Some people work there and some ride the trains to take in its visuals—people and architecture. In a Thomas Pynchon novel, characters amuse themselves by riding the subway back and forth, again and again, in any direction. Some people use it for no more than to get from place to place.  Some people avoid it as an eyesore and crime risk. Crowded or sparse, it’s open 24 hours a day.