The 81st Street–Museum of Natural History station is a local station on the IND Eighth Avenue Line of the New York City Subway. It is served by the B on weekdays, the C train at all times except nights, and the A train during late nights only. History The station opened on September 10, 1932, as part of the city-operated Independent Subway System (IND)'s initial segment, the Eighth Avenue Line between Chambers Street and 207th Street. Construction of the whole line cost $191.2 million (equivalent to $ million in . While the IRT Broadway–Seventh Avenue Line already provided parallel service, the new Eighth Avenue subway via Central Park West provided an alternative route. The station was renovated in 1998–2000, in coordination with building the new Hayden Planetarium, within the Rose Center for Earth and Space. The floors were replaced, new lighting was installed, the token booth was upgraded, and the walls and staircases were re-tiled. Structural improvements were also made during the renovation. In 2019, the Metropolitan Transportation Authority announced that the station would become ADA-accessible as part of the agency's 2020–2024 Capital Program. Station layout This underground station has four tracks and two side platforms. On this section of the line, the local tracks are stacked, uptown above downtown, and the express tracks are stacked in the same order to the east of them, so both platforms are on the west side, one above the other. The station is at Central Park West and 81st Street, rather than the major crosstown 79th Street, in order to accommodate the American Museum of Natural History, which largely fills the area of what was once called the Manhattan Square. The 79th Street Transverse Road, through Central Park, exits the park here. South of this station are storage/lay up tracks between the local and express tracks on each level. Both ends of the tracks merge with the express tracks, with switches to the local tracks. Exits There are two fare control areas, both on the upper platform. One is at the station's extreme south end, on Central Park West midblock between 77th and 81st Streets. From this fare control, a passageway leads to a staircase on the west side of Central Park West, just south of the American Museum of Natural History's front entrance. This fare control also has an underground entrance directly into the museum's lowest level. The other is at the