Abstract: The system comprises a brake cylinder with incorporated spring brake (1), associated with each wheel of at least one axle and able to perform air braking when both its inlets (1a, 1b) are under pressure, spring braking when a second inlet (1b) thereof is discharged, and release of spring braking when pressurised air is supplied again to the second inlet (1b); a valve control unit (7) including a relay valve (8) having a control inlet (8a) connected to the air line or pipe (3) for braking while parking, a further inlet (8b) connected to the first line or pipe (2) for service braking, and an outlet (8c) connected to the first inlet (1a) of the brake cylinder (1) associated with each wheel of said at least one axle; and a double non-return valve (11) having a first and a second inlet (11a, 11b) connected to the outlet (8c) of the relay valve (8) and, respectively, to the service braking line or pipe (2), and the outlet (11c) connected to the first inlet (1a) of the abovementioned brake cylinders (1).