A brake system for a rail vehicle including a brake cylinder having a housing, a port on the housing for receiving fluid pressure signals, a pressure piston carried inside the housing, and a shaft inside the housing. The shaft is connected at one end to the pressure piston and at the other end to a device to apply and release the brakes of the rail vehicle. A parking brake locking mechanism is located inside the housing and includes first and second elements cooperating to lock and unlock the parking brake locking mechanism. Further included is means for unlocking the parking brake locking mechanism from the locked position.