The New York City Subway is a heavy-rail public transit system serving four of the five boroughs of New York City. The present New York City Subway system inherited the systems of the Interborough Rapid Transit Company (IRT), Brooklyn–Manhattan Transit Corporation (BMT), and the Independent Subway System (IND). New York City has owned the IND since its inception; the BMT and IRT were taken over by the city in 1940. The former IRT system is now known as the A Division, while the B Division is the combined former BMT and IND systems.

In the New York City Subway nomenclature, a "line" refers to the physical trackage that is used by numbered or lettered "services", which change periodically. Today, the division or company names are not used publicly, while the line names may occasionally be used.

Nomenclature

In the nomenclature of the subway, the terms "line" and "service" are not interchangeable with each other. While in popular usage the word "line" is often used synonymously with "service" (even sometimes on the website of the MTASubway Line Information ), this list will use the formal usage of the term "line."

A line is the physical structure and tracks that trains run over. Each section of the system is assigned a unique line name that begins with a division (IRT, BMT or IND), which is its pre-unification division when applicable. For example, the line under Eighth Avenue is the IND Eighth Avenue Line. Some lines have changed names (and even divisions), but this happens relatively infrequently.

By contrast, a service refers to the route that a train takes across the various lines. A service can operate along several lines and even along different divisions. For example, the service operates along the IND Queens Boulevard Line as well as the BMT Broadway Line and the BMT Fourth Avenue Line.

Each service is assigned a color. Since 1979, each service's color corresponds to the line it primarily uses in Midtown Manhattan—defined as the trunk line. There are three exceptions: the IND Crosstown Line, which does not carry services to Manhattan, is colored ; the BMT Nassau Street Line, which runs only through Lower Manhattan, is colored ; and all shuttles are colored . The list of trunk lines and colors is shown in the table below.

Line listing

There are currently rail lines. The Archer Avenue Lines and the 63rd Street Lines are each classified as two separate lines due to their structure: both lines have distinct sections that are chained as BMT and the IND lines.

In the list below, lines with colors next to them indicate trunk lines, which determine the colors that are used for services' route bullets and diamonds, as well as shuttle service lines. The opening date refers to the opening of the first section of track for the line. In the "division" column, the current division is followed by the original division in parentheses.

Division Line Opened Structure B (IND) 02Second Avenue Line Manhattan underground B (BMT) Fourth Avenue Line Brooklyn underground B (IND) 06Sixth Avenue Line ManhattanBrooklyn underground B (IND) 08Eighth Avenue Line ManhattanBrooklyn underground A (IRT) 42nd Street Shuttle Manhattan underground B (BMT) 63rd Street Line Manhattan underground B (IND) 63rd Street Line ManhattanQueens underground B (BMT) Archer Avenue Line Queens underground B (IND) Archer Avenue Line Queens underground B (BMT) Astoria Line Queens elevated B (BMT) Brighton Line Brooklyn underground, open cut, at-grade, embankment, elevated B (BMT) Broadway Line Manhattan underground A (IRT) Broadway–Seventh Avenue Line BronxManhattanBrooklyn elevated, embankment, underground B (BMT) Canarsie Line BrooklynManhattan underground, elevated, at-grade B (IND) Concourse Line BronxManhattan underground B (IND) Crosstown Line BrooklynQueens underground B (IND) Culver Line Brooklyn underground, elevated A (IRT) Dyre Avenue Line Bronx elevated, embankment, open-cut, underground A (IRT) Eastern Parkway Line Brooklyn underground A (IRT) Flushing Line QueensManhattan underground, elevated B (BMT) Franklin Avenue Line Brooklyn elevated, embankment, open cut B (IND) Fulton Street Line BrooklynQueens underground, elevated B (BMT) Jamaica Line BrooklynQueens elevated A (IRT) Jerome Avenue Line Bronx elevated, underground A (IRT) Lenox Avenue Line Manhattan at-grade, underground A (IRT) Lexington Avenue Line Manhattan underground B (BMT) Myrtle Avenue Line BrooklynQueens elevated, embankment, at-grade B (BMT) Nassau Street Line Manhattan underground A (IRT) New Lots Line Brooklyn elevated A (IRT) Nostrand Avenue Line Brooklyn underground A (IRT) Pelham Line Bronx underground, elevated B (IND) Queens Boulevard Line QueensManhattan underground B (IND) Rockaway Line Queens at-grade, embankment, elevated B (BMT) Sea Beach Line Brooklyn open cut, elevated B (BMT) West End Line Brooklyn open-cut, elevated A (IRT) White Plains Road Line Bronx elevated, underground

Inter-division connections The following list shows the connections between the different divisions of the New York City Subway.

Purpose-built

These connections can be used by trains in revenue service: 60th Street Tunnel Connection, also known as the 11th Street Cut (Queens) (BMT/IND) ( train) 63rd Street Lines (Manhattan) (BMT/IND) Coney Island–Stillwell Avenue station (BMT/IND) (originally all BMT) ( trains) Chrystie Street Connection (Manhattan) (BMT/IND) via the Manhattan Bridge ( trains) and via the Williamsburg Bridge ( train)

This connection is not for revenue service due to the differing widths of the trains: Astoria Line / Flushing Line (Queens) (BMT/IRT)

Yards

These connections are located within the subway's rail yards and are not intended for revenue service. 207th Street Yard (Manhattan) (IND/IRT); trains from the IND Eighth Avenue Line and IRT Broadway–Seventh Avenue Line Coney Island Complex (Brooklyn) (BMT/IND); trains from the IND Culver Line, BMT Sea Beach Line and BMT West End Line Concourse Yard (Bronx) (IND/IRT); trains from the IND Concourse Line and IRT Jerome Avenue Line Linden Yard (Brooklyn) (BMT/IRT/LIRR); trains from the BMT Canarsie Line and IRT New Lots Line

To the national rail network

BMT West End Line / South Brooklyn Railway (Brooklyn) (BMT/Mainline RR) Linden Yard/Bay Ridge Branch (LIRR) (Brooklyn) (BMT/IRT/LIRR); trains from the BMT Canarsie Line and IRT New Lots Line Unused connections in the same division In some places, there are track connections within the same division that are unused in regular service.

Brooklyn At Coney Island–Stillwell Avenue, see above. At Broadway Junction, there is an unused flyover between the BMT Canarsie Line and the BMT Jamaica Line. At Prospect Park, the tracks of the BMT Franklin Avenue Line become the local tracks of the BMT Brighton Line. At DeKalb Avenue, there is an unused connection between the BMT Brighton Line and the BMT Broadway Line via the Montague Tunnel.

Manhattan At West Fourth Street–Washington Square, there is an unused connection between the local tracks of the IND Eighth Avenue Line and those of the IND Sixth Avenue Line. Between Bowling Green and the South Ferry loops, the IRT Lexington Avenue Line and the IRT Broadway–Seventh Avenue Line have crossovers on the balloon loop tracks. On the 42nd Street Shuttle, there are track connections to the IRT Broadway–Seventh Avenue Line at the west end and the IRT Lexington Avenue Line at the east end. It is not possible to operate through service on this line (i.e. one cannot go from the Broadway –Seventh Avenue Line to the Lexington Avenue Line using the shuttle tracks and vice versa), though the tracks are used to transport trains to and from Livonia Yard in Brooklyn. South of Broad Street on the BMT Nassau Street Line, the two-track line widens to four tracks. The two inner tracks are used to store and turn trains, while the two outer tracks continue to the Montague Street Tunnel and to the BMT Fourth Avenue Line in Brooklyn.

Queens On the IND Rockaway Line, a single track connects the branches of the wye at Hammels, south of Broad Channel, this was used previously for round-robin shuttle service and emergency service.

Unused center tracks Many of the New York City Subway's lines have express tracks, unused in regular service and generally only used for re-routes.

The Bronx IRT Jerome Avenue Line: Single center track between 149th Street–Grand Concourse and Woodlawn. Some northbound trains in the morning and afternoon rush hours operate express from 167th Street until Burnside Avenue, where they short-turn. IRT White Plains Road Line: Single center track between East 180th Street and Wakefield–241st Street. IRT Dyre Avenue Line: Combinations of track and right of way between the flyover and Dyre Avenue. IRT Pelham Line: Single center track between Parkchester and Pelham Bay Park. IRT Broadway–Seventh Avenue Line: Single center track between Dyckman Street and 242nd Street.

Brooklyn BMT Sea Beach Line: One center track between 86th Street and Eighth Avenue. These were originally a pair of tracks which were briefly used by the service in 1967–1968; in 1999, one of the tracks was rehabilitated and the other was disconnected from the line leaving it unusable. The track is used occasionally for reroutes in either direction and possibly equipment testing. In the past, these tracks have been used to store rolling stock that are about to be scrapped. BMT West End Line: Single center track between Ninth Avenue and Bay 50th Street. Occasionally used for reroutes in either direction. BMT Brighton Line: Two center tracks between Brighton Beach and Ocean Parkway. These are used for layups and for terminating/turning trains but are listed here since they are a continuation of the express tracks from the Brighton line, and exist through Ocean Parkway station. IND Culver Line: Single center track between Church Avenue and Avenue X. BMT Jamaica Line: Single center track between Myrtle Avenue and Broadway Junction.

Manhattan IRT Broadway–Seventh Avenue Line: Single center track between 96th Street and 145th Street. IRT Lenox Avenue Line: Single center track at 135th Street.

Queens BMT Astoria Line: Single center track between 39th Avenue and Astoria –Ditmars Boulevard. This track was last used for trains in the peak direction, and being unpopular with residents, was discontinued on January 15, 2002. IND Fulton Street Line and IND Rockaway Line: On the Fulton Street Line, a single center track between Rockaway Boulevard and west of 88th Street (the track continues through 80th Street but leads only to the Pitkin Yard), and two center tracks from north of Aqueduct to south of Howard Beach–JFK Airport on the IND Rockaway Line.

Non-underground sections

Despite "subway" implying underground travel, the following segments are located above ground or at grade level and comprise about 40% of the trackage.

The Bronx IRT Broadway–Seventh Avenue Line from south of 231st Street to Van Cortlandt Park–242nd Street IRT Jerome Avenue Line from 149th Street–Grand Concourse to Woodlawn IRT White Plains Road Line from Third Avenue–149th Street to Wakefield–241st Street Entire IRT Dyre Avenue Line, except for Pelham Parkway IRT Pelham Line from Hunts Point Avenue to Pelham Bay Park

Brooklyn BMT Jamaica Line from west of Marcy Avenue (on the Williamsburg Bridge) to 75th Street–Elderts Lane BMT Myrtle Avenue Line from west of Central Avenue to Myrtle–Wyckoff Avenues Entire IRT New Lots Line Entire BMT Sea Beach Line Entire BMT West End Line BMT Canarsie Line at Wilson Avenue (southbound platform elevated, northbound platform is actually on street level but in tunnel below elevated southbound platform), and from Broadway Junction to Canarsie–Rockaway Parkway IND Culver Line from south of Carroll Street to Fourth Avenue/Ninth Street, and south of Church Avenue to Coney Island–Stillwell Avenue BMT Brighton Line from Prospect Park to Coney Island–Stillwell Avenue Entire BMT Franklin Avenue Line Both Manhattan Bridge lines