The 125th Street station is an express station with four tracks and two island platforms. It is the northernmost Manhattan station on the IRT Lexington Avenue Line of the New York City Subway. Located at Lexington Avenue and East 125th Street (also known as Dr. Martin Luther King, Jr. Boulevard) in East Harlem, it is served by the 4 and 6 trains at all times, the 5 train at all times except late nights, and the <6> train during weekdays in peak direction. This station was constructed as part of the Dual Contracts by the Interborough Rapid Transit Company and opened in 1918. A planned northern extension of the Second Avenue Subway would connect with this station and with the Metro-North Railroad's Harlem–125th Street station, located one block west.
