A rail vehicle braking system with brakes that have at least one lining or at least one block, comprising: - a body (2; 102; 202; 302; 402); - 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 (8; 108; 408) which is movable relative to said body to act on said braking linkage and delimits with said body a service brake pressure chamber (13; 113; 413) configured to be supplied by a first source of pneumatic pressure agent (50, 51, 53) 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 braking piston is disposed in said body and has two sides, respectively a first side (17; 117) configured to act on said braking linkage and a second side (18; 118) which is an opposite side to said first side and which is turned towards said service brake pressure chamber; - said service brake further comprises a piston rod (21; 121; 221; 321; 421) disposed in said service brake pressure chamber and attached to said second side of said braking piston; - said parking brake is disposed in said body and comprises a blocking device (20; 120; 220; 320; 420) disposed in said service brake pressure chamber, which device is movable relative to said body to act on said piston rod and having a first position and a second position, as well as an actuating device (23, 24; 123, 124, 180; 223, 280; 323, 380; 423, 424) which is movable relative to said body, delimiting with said body a parking brake pressure chamber (25; 125; 225; 325; 425) configured to be supplied by a second source of pneumatic pressure agent, and having a stable position; said blocking device and said actuating device being configured such that: - when said braking piston is in its service braking position and said parking brake is in working configuration, said actuating device acts on said blocking device until the latter immobilizes said piston rod so as to block said braking piston in its service braking position, said blocking device then being in its second position and said actuating device in its stable position; and - when said parking brake is in resting configuration, said actuating device acts on said blocking device until the latter frees said piston rod so as to unblock said braking piston from its service braking position, said blocking device thus being in its first position; whereby the braking force applied to said braking linkage when said parking brake is in working configuration is directly related to the braking force applied to said braking linkage by said service brake in its service braking position, independently of the force applied by said blocking device on said piston rod. - a body (2; 102; 202; 302; 402); - 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 (8; 108; 408) which is movable relative to said body to act on said braking linkage and delimits with said body a service brake pressure chamber (13; 113; 413) configured to be supplied by a first source of pneumatic pressure agent (50, 51, 53) 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 braking piston is disposed in said body and has two sides, respectively a first side (17; 117) configured to act on said braking linkage and a second side (18; 118) which is an opposite side to said first side and which is turned towards said service brake pressure chamber; - said service brake further comprises a piston rod (21; 121; 221; 321; 421) disposed in said service brake pressure chamber and attached to said second side of said braking piston; - said parking brake is disposed in said body and comprises a blocking device (20; 120; 220; 320; 420) disposed in said service brake pressure chamber, which device is movable relative to said body to act on said piston rod and having a first position and a second position, as well as an actuating device (23, 24; 123, 124, 180; 223, 280; 323, 380; 423, 424) which is movable relative to said body, delimiting with said body a parking brake pressure chamber (25; 125; 225; 325; 425) configured to be supplied by a second source of pneumatic pressure agent, and having a stable position; - when said braking piston is in its service braking position and said parking brake is in working configuration, said actuating device acts on said blocking device until the latter immobilizes said piston rod so as to block said braking piston in its service braking position, said blocking device then being in its second position and said actuating device in its stable position; and - when said parking brake is in resting configuration, said actuating device acts on said blocking device until the latter frees said piston rod so as to unblock said braking piston from its service braking position, said blocking device thus being in its first position;