B service ends early each night. Coney Island -bound D trains skip 155th Street.
FASTRACK was introduced in January 2012, devoting four straight weeknights to perform maintenance work in tunnels, stations and on tracks, completely suspending service within a given line segment for a seven-hour period between. This gives free access to the system, allowing an army of maintenance workers to perform dozens of tasks without the concern of having to "clear up" to allow trains to pass.
The next FASTRACK overnight closure will be August 12-16 on the Queens Blvd Line between 5th Avenue-53rd Street E, M and Roosevelt Avenue and between 21st Street-Queensbridge F and Roosevelt Avenue.