In New York, routings change often as new connections are opened or service patterns change. Many rapid transit systems run relatively static routings, so that a train 'line' is more or less synonymous with a train 'route'.

Main articles: New York City Subway nomenclature and List of New York City Subway lines All of these modes are completely grade-separated from road and pedestrian crossings, and most crossings of two subway tracks are grade-separated with flying junctions. Though it is known as 'the subway,' implying underground operations, about 40% of the system runs on above-ground rights-of-way, including steel and occasionally cast iron elevated structures, concrete viaducts, earthen embankments, open cuts and, occasionally, surface routes. The Staten Island Railway operates with R44 subway cars on a fully grade-separated right-of-way, but is typically not considered part of the subway, and is connected only via the free, city-operated Staten Island Ferry. Pending legislation would merge the subway operations of MTA New York City Transit with Staten Island Railway to form a single entity called MTA Subways. There are 656 miles (1056 km) of revenue track, and a total of 842 miles (1355 km) including non-revenue trackage. Combined with its bus operations, it is one of the most extensive public transportation systems in the world, with 472 reported passenger stations. The New York City Subway system is a rapid transit system operated by the New York City Transit Authority, an affiliate of the Metropolitan Transportation Authority as MTA New York City Transit.

New york city subway