The Independent Subway System (IND or ISS), formerly known as the Independent City-Owned Subway System (ICOS) or the Independent City-Owned Rapid Transit Railroad, was a rapid transit rail system in New York City that is now part of the New York City Subway. It was first constructed as the "Eighth Avenue Line" in Manhattan in 1932.
One of three rail networks that became part of the modern New York City subway, the IND was intended to be fully owned and operated by the municipal government, in contrast to the privately operated or jointly-funded Interborough Rapid Transit Company (IRT) and Brooklyn–Manhattan Transit Corporation (BMT) companies. It was merged with these two networks in 1940.
The original IND service lines are the modern subway's A, B, C, D, E, F and G services. In addition, the BMT's M and R now run partly on IND trackage. The Rockaway Park Shuttle supplements the A service. For operational purposes, the IND and BMT lines and services are referred to jointly as the B Division.
Rapid transit, also known as metro, subway or underground is a type of high-capacity public transport generally found in urban areas. Unlike buses or trams, rapid transit systems are electric railways that operate on an exclusive right-of-way, which cannot be accessed by pedestrians or other vehicles of any sort, and which is often grade separated in tunnels or on elevated railways.
Modern services on rapid transit systems are provided on designated lines between stations typically using electric multiple units on rail tracks, although some systems use guided rubber tyres, magnetic levitation, or monorail. The stations typically have high platforms, without steps inside the trains, requiring custom-made trains in order to avoid gaps. They are typically integrated with other public transport and often operated by the same public transport authorities. However, some rapid transit systems have at-grade intersections between a rapid transit line and a road or between two rapid transit lines. It is unchallenged in its ability to transport large numbers of people quickly over short distances with little use of land. Variations of rapid transit include people movers, small-scale light metro, and the commuter rail hybrid S-Bahn.