History of the IRT subway before 1918

The first regularly operated subway in New York City was built by the city and leased to the Interborough Rapid Transit Company for operation under Contracts 1 and 2 of the Dual Contracts. Until 1918, when the new "H" system that is still operated—with separate East Side and West Side lines—was placed in service, it consisted of a single trunk line below 96th Street with several northern branches. The system had four tracks between Brooklyn Bridge–City Hall and 96th Street, allowing for local and express service on that portion. Under the "H" system, the original line and early extensions are now as follows:

Planning for the system that was built began with the Rapid Transit Act, signed into law on May 22, 1894, which created the Board of Rapid Transit Railroad Commissioners. The act provided that the commission would lay out routes with the consent of property owners and local authorities, either build the system or sell a franchise for its construction, and lease it to a private operating company. A line through Lafayette Street (then Elm Street) to Union Square was considered, but at first a more costly route under lower Broadway was adopted. A legal battle with property owners along the route led to the courts denying permission to build through Broadway in 1896. The Elm Street route was chosen later that year, cutting west to Broadway via 42nd Street. This new plan, formally adopted on January 14, 1897, consisted of a line from City Hall north to Kingsbridge and a branch under Lenox Avenue and to Bronx Park, to have four tracks from City Hall to the junction at 103rd Street. The "awkward alignment...along Forty-Second Street", as the commission put it, was necessitated by objections to using Broadway south of 34th Street. Legal challenges were finally taken care of near the end of 1899.

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