The New York City Subway is a rapid transit system in New York City, United States. It is run by the Metropolitan Transportation Authority (MTA). 

It is one of the biggest rapid transit systems in the world, with 472 stations. It has 245 miles (or 394 km) of routes on 691 miles (or 1112 km) of railway track.
The New York City Subway almost never closes; the trains run 24 hours a day, 7 days a week, all year. The system has only closed three times, most notably during the September 11 attacks and when Hurricane Sandy flooded its tracks. 

There are three different types of subway services. "Local" trains make all stops at "local" stations as well as at "express" stations. "Express" trains skip local stations, but stop at "express" stations. There is one "skip-stop" service, the J/Z, where two train routes run on the same line; each route only stops at every other station along the line. 

"Now Tucker Mouse had heard almost all the sounds that can be heard in New York City. He had heard the rumble of subway trais and the shriek of their iron wheels make when they go around a corner. (p. 7)

"the train lurched to a halt. Like most people who first ride the subway, Chester wasn't used to the abrupt stops. (p. 43)

Most of our story in Selden's book takes place in the subway station below Times Square in New York City. This station is one of the original subway stations in New York City built in the early 1900s. Located next to the Port Authority Bus Terminal, the station complex is one of the city's busiest, serving more than 65 million passengers in 2019. Above the station, Times Square is a center of New York City entertainment and tourism. Thousands of people, day and night, flock to its theatres, hotels, restaurants and shops, all lit from above by constantly flashing, larger-than-life neon signage. 

There are subway stations in Manhattan, Brooklyn, Queens, and the Bronx. About 40% of the tracks are above ground and the other 60% are below ground. Every day about 5,076,000 people take rides on the subway. 463 out of the system's 472 stations are always open. 

Many stations have "mezzanines". These are the levels of the station where you pay a fare before entering the subway platforms. Everyone must pay a fare to enter the subway system. They are usually between street level and platform level.

Most subway stations have waiting platforms that are from 480 to 600 feet (150 to 180 m) long. People wait for trains on these platforms.

Many stations also have artwork on the subway station walls.

Most of the stations wers built before 1990. That is when a new law said that many new buildings, like subway stations, should have elevators and ramps so people with wheelchairs can enter these buildings.

The MTA has run the "Music Under New York" (MUNY) program in the subway since 1987. People must compete in order to be allowed to play music in a station. There are now more than 100 musicians and performers in the subway system.

There are only 129 open restrooms in 77 of the system's stations.

Some platforms have newspaper stands as well. They sell many things, including newspapers and food. There are also stores in some stations.