A rail vehicle braking system with brakes that have at least one lining or at least one block, comprising: - a body; - a braking linkage configured to act on at least one said brake that has at least one lining or at least one block; - a service brake comprising a braking piston which is movable relative to said body to act on said braking linkage and delimits with said body a service brake pressure chamber configured to be supplied by a first source of pneumatic pressure agent (50, 51, 53, 57; 153; 253) to put said braking piston into a service braking position; and - a parking brake configured to act on said braking piston of said service brake and having a working configuration and a resting configuration; said rail vehicle braking system being characterized in that said parking brake comprises: - a blocking device which is movable relative to said body to act on said braking piston and having a first position and a second position in which said blocking device is configured to immobilize said braking piston in service braking position, said parking brake then being in working configuration; - an actuating device (23, 24) movable relative to said body, delimiting with said body a parking brake pressure chamber configured to be supplied by a second source of pneumatic pressure agent (50, 51, 54, 58; 154; 254), and having a stable position in which said actuating device (23, 24) is configured to hold said blocking device in its second position; said rail vehicle braking system being configured such that, when said actuating device (23, 24) is in its stable position, said service brake pressure chamber is supplied by said second source of pneumatic pressure agent (50, 51, 54, 58; 154; 254), of which the pressure is greater than that of said first source of pneumatic pressure agent (50, 51, 53, 57; 153; 253), in order to apply, when said parking brake is in working configuration, a greater braking force than the braking force applied when said braking piston is in its service braking position and said parking brake is in its resting configuration. - a body; - a braking linkage configured to act on at least one said brake that has at least one lining or at least one block; - a service brake comprising a braking piston which is movable relative to said body to act on said braking linkage and delimits with said body a service brake pressure chamber configured to be supplied by a first source of pneumatic pressure agent (50, 51, 53, 57; 153; 253) to put said braking piston into a service braking position; and - a parking brake configured to act on said braking piston of said service brake and having a working configuration and a resting configuration; - a blocking device which is movable relative to said body to act on said braking piston and having a first position and a second position in which said blocking device is configured to immobilize said braking piston in service braking position, said parking brake then being in working configuration; - an actuating device (23, 24) movable relative to said body, delimiting with said body a parking brake pressure chamber configured to be supplied by a second source of pneumatic pressure agent (50, 51, 54, 58; 154; 254), and having a stable position in which said actuating device (23, 24) is configured to hold said blocking device in its second position;