The Court Square–23rd Street station is a New York City Subway station complex on the IND Crosstown Line, the IRT Flushing Line and the IND Queens Boulevard Line. The complex is located in the vicinity of One Court Square in Hunters Point and Long Island City, Queens, and is served by the 7, E, and G trains at all times; the M train on weekdays; and the <7> express train during weekdays in the peak direction. The complex comprises three originally separate stations, formerly known as the 23rd Street–Ely Avenue station (Queens Boulevard Line), Long Island City–Court Square station (Crosstown Line), and 45th Road–Court House Square station (Flushing Line). The Flushing Line station was the first to open, in 1916. The Crosstown Line station opened in 1933, followed by the Queens Boulevard Line station in 1939. Two passageways were built to connect the three stations. The first was built in 1990, following the opening of the Citigroup office tower at One Court Square. In December 2001, this passageway came into greater use when G trains started to terminate at Court Square. A second passageway was completed between the Crosstown and Flushing Line stations in 2011. The Crosstown and Flushing Line stations were renamed "Court Square" with the latter being made fully ADA-accessible. The Queens Boulevard Line station, which is not ADA-compliant, was renamed "Court Square–23rd Street". From Wikipedia
