A parking brake for a body mounted brake cylinder having either a single locking mechanism cooperates with a threaded shaft that is centrally mounted within the brake cylinder or with multiple locking mechanisms that are positioned symmetrically about the centerline of the brake cylinder push rod so that the push or piston rod can still accommodate arcuate motion of the level of the braking system. The locking mechanism may be controlled by a mechanical linkage or through a pneumatic circuit. Activation of the locking mechanisms prevents axial movement of the brake piston. As a result, engagement of the locking mechanism may be used to prevent a release of the brakes after then have been applied to provide an automatic parking brake.