New York City Subway nomenclature

New York City Subway nomenclature is the terminology used in the New York City Subway system as derived from railroading practice, historical origins of the system, and engineering, publicity, and legal usage. Important terms include lines, or individual sections of subway, like the BMT Brighton Line; services, like the B, which is a single train route along several lines; and stations, such as Coney Island – Stillwell Avenue, which connects multiple lines and services.

Lines and services on the New York City Subway are often confused with each other. Lines are physical train tracks, while services are the routes that use the tracks. This distinction is also made on other systems, including the Washington Metro and Taipei Metro, although the exact terms used differ.

Each section of subway has three identifying characteristics, line, service and color.

The most constant is the line, the physical structure and tracks that trains run over. Each section of the system is assigned a unique line name, usually paired with its original operating company or division (Brooklyn–Manhattan Transit Corporation (BMT), Interborough Rapid Transit Company (IRT), Independent Subway System (IND)). 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.

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