Brake system for railway vehicles

A brake system for a rail vehicle having at least two bogies comprising:

• a main air reservoir line fed by a compressed-air generating device;
• a compressed-air line connecting the main air reservoir line with a pneumatic brake unit on each bogie;
• the pneumatic brake unit including a relay valve controlling pressure in a spring-loaded brake on an output of the relay valve with pressure at an input of the relay valve in response to an air control signal, an electro-pneumatic pressure control device providing a first air control signal, an emergency pressure device providing a second air control signal, and an electro-pneumatic switch-over device for selecting one of the two air control signals for the relay valve;
• and
• an electrical control system at each bogie controlling the electro-pneumatic pressure control device and the electro-pneumatic switch-over device in response to electrical braking signals, the electrical control system using the electro-pneumatic pressure control device for service and emergency electrical braking signals and controls the switch-over device to select the second air control signal if emergency braking is not correctly initiated by the electro-pneeumatic pressure control device.