These pictures are from a tour I took of the abandoned City Hall subway station in New York City. The station was the South terminus of the original (Interborough Rapid Transit) IRT subway line that stretched all the way uptown to 145th street.
The City Hall Station was permanently closed on December 31st 1945, but the tracks in the station are still used by the 6 train to turn around from the southbound to the northbound track of the Brooklyn Bridge/ City Hall station.
The station was closed for a number of reasons, chief among them was that the City Hall station is a tight loop that left a huge gap between the platform and the train once trains with side doors started being used. Originally, subway cars only had entrances at the front and rear of the car, so having a large gap in the center of a car wasn’t a concern. Other factors also played a role in the closing of the City Hall station, including the inability to lengthen the station once longer trains started being used, the close proximity to an express station, and the location right under City Hall, making it inconvenient to get to by anyone except people in City Hall.