Fluid parking brake for a rail vehicle air brake cylinder

The present invention relates generally to rail vehicle air brakes and more specifically, to a fluid operated parking brake therefore. A fluid parking brake for a rail vehicle having a brake cylinder with a first piston responsive to fluid signals to apply and release the brakes on the vehicle. The parking brake includes a housing having a second piston in the housing and which is coupled to the first piston. An apply port in the housing receives a pressure signal to move the second piston to an apply position. A locking clutch is provided for locking the second piston in the applied position.