Parking locking brake cylinder for rail transit vehicle

The invention discloses a parking locking brake cylinder for a rail transit vehicle. The parking locking brake cylinder comprises a brake cylinder body, a brake cylinder cover, a parking locking cylinder cover, a locking mechanism, a manual relieving mechanism, a piston assembly, a gap adjusting mechanism and a main shaft lead screw. The parking braking function is the core function of the braking clamp unit, and parking braking force is generated. For a parking brake function, a spring energy storage type parking brake cylinder is mostly adopted for achieving the parking brake function, when parking brake is relieved, compressed air is filled into the parking brake cylinder, and a spring is compressed; when the parking brake is applied, compressed air in the parking cylinder is discharged, and the spring force is released to apply the parking brake; and when the parking brake is manually relieved, the parking brake is relieved through the manual relieving mechanism. A novel locking mechanism and a manual rel