Abstract: A hydraulic brake system for vehicles, particularly light rail vehicles, includes at least one brake actuator for engaging the brake by means of a group of springs and disengaging the brake by hydraulic pressure. The system comprises an electric drive motor and pump for supplying pressurized hydraulic fluid to the actuator, and a safety valve and solenoid valves for controlling the pressure of the hydraulic fluid in the actuator. An accumulator is connected to the electric drive motor and pump for delivering the pressurized hydraulic fluid via valves and restriction for adjusting the pressure in the accumulator to a value substantially inversely proportional to the load of the vehicle. It is connected to the actuator by shuttle valves controlled by the pressure of the accumulator when the control safety valve and solenoid valves are actuated to relieve hydraulic fluid from the actuator.