125th Street station (IRT Lenox Avenue Line)

Planning for the city's first subway line dates to the Rapid Transit Act, authorized by the New York State Legislature in 1894.[3]^:139–140 The subway plans were drawn up by a team of engineers led by William Barclay Parsons, chief engineer of the Rapid Transit Commission. It called for a subway line from New York City Hall in lower Manhattan to the Upper West Side, where two branches would lead north into the Bronx.[4]^:3 A plan was formally adopted in 1897, and legal challenges were resolved near the end of 1899.[3]^:148 The Rapid Transit Construction Company, organized by John B. McDonald and funded by August Belmont Jr., signed Contract 1 with the Rapid Transit Commission in February 1900,[5] in which it would construct the subway and maintain a 50-year operating lease from the opening of the line.[3]^:182 In 1901, the firm of Heins & LaFarge was hired to design the underground stations.[4]^:4 Belmont incorporated the Interborough Rapid Transit Company (IRT) in April 1902 to operate the subway.[3]^:182

The 125th Street station was constructed as part of the IRT's East Side Branch (now the Lenox Avenue Line). Farrell & Hopper began building the section from 110th Street to 135th Street on August 30, 1900, subcontracting the section north of 116th Street to John C. Rodgers.[5][6]^:252 The excavation was relatively easy because the subway was under one side of Lenox Avenue and there were no street railway tracks to work around.[6]^:252–253

On November 23, 1904, the East Side Branch opened to 145th Street.[7][8] Initially, the station was served by East Side local and express trains. Local trains ran from City Hall to Lenox Avenue (145th Street). Express trains had their southern terminus at South Ferry or Atlantic Avenue and had their northern terminus at 145th Street or West Farms (180th Street).[9] Express trains to 145th Street were eliminated in 1906, and West Farms express trains operated through to Atlantic Avenue in Brooklyn.[10]

In 1909, to address overcrowding, the New York Public Service Commission proposed lengthening platforms at stations along the original IRT subway.[11]^:168 On January 18, 1910, a modification was made to Contracts 1 and 2 to lengthen station platforms to accommodate ten-car express and six-car local trains. In addition to $1.5 million (equivalent to $41.2 million in 2019) spent on platform lengthening, $500,000 (equivalent to $13,719,643 in 2019) was spent on building additional entrances and exits. It was anticipated that these improvements would increase capacity by 25 percent.[12]^:15 The platforms at the 125th Street station were extended 55 feet (17 m) to both the north and south.[12]^:112 On January 23, 1911, ten-car express trains began running on the East Side Branch.[11]^:168[13]

In 1918, the Broadway–Seventh Avenue Line opened south of Times Square–42nd Street, thereby dividing the original line into an "H" system. Local trains were sent to South Ferry, while express trains used the new Clark Street Tunnel to Brooklyn.[14] The services at the station became 2 (West Farms express) and 3 (Lenox Avenue local) in 1948.[15] In 1959, all 2 and 3 trains became express.[16]

On May 23, 1968, poet Henry Dumas was fatally shot by a New York City Transit Police officer on the station's southbound platform.[17]

In 1981, the MTA listed the station among the 69 most deteriorated stations in the subway system.[18] Starting on March 2, 1998, the tunnel was reconstructed along with the cracked tunnel floor. This was done to correct a major water problem that had existed for many years due to the presence of the Harlem Creek and other underground streams, which caused extensive flooding, water damage, and seepage problems that occasionally contributed to severe service disruptions.[19][20] The project cost $82 million and was finished on October 12, 1998.[19][21] During the reconstruction, many 2 trains were rerouted via the IRT Lexington Avenue Line, while the 3 trains were rerouted to the 137th Street–City College station on the IRT Broadway–Seventh Avenue Line. Each of the two Lenox Avenue Line tracks were alternately taken out of service and supplemental shuttle bus service connecting to other lines in the area were provided for much of this time.[22][23]

As with other stations built as part of the original IRT, the tunnel is covered by a "U"-shaped trough that contains utility pipes and wires. The bottom of this trough contains a foundation of concrete no less than 4 inches (100 mm) thick.[27]^:9 The platforms consist of 3-inch-thick (7.6 cm) concrete slabs, beneath which are drainage basins. The original platforms contain circular, cast-iron Doric-style columns spaced every 15 feet (4.6 m), while the platform extensions contain I-beam columns. Additional columns between the tracks, spaced every 5 feet (1.5 m), support the jack-arched concrete station roofs.[4]^:4[27]^:9 There is a 1-inch (25 mm) gap between the trough wall and the platform walls, which are made of 4-inch (100 mm)-thick brick covered over by a tiled finish.[27]^:9

The original decorative scheme consisted of blue tile station-name tablets, pink tile bands, a green terracotta cornice, and dark blue terracotta plaques. The decorative work was performed by tile contractor Manhattan Glass Tile Company and terracotta contractor Atlantic Terra Cotta Company.[27]^:42 The station has new name tablets, although some old "125" terracotta cartouches are still visible.

The artwork in the station is Flying Home: Harlem Heroes and Heroines, by Faith Ringgold, installed in 1996.[28]

Two staircases from each platform lead to the intersection of Lenox Avenue and West 125th Street. The staircases from the southbound platform lead to the western corners, while those from the northbound platform lead to the eastern corners.[29]