Brake control valve arrangement

An electropneumatic brake system for a rail vehicle configured to provide emergency braking, the electropneumatic brake system comprising:

• brake cylinders for applying a brake force;
• emergency regulator valve that has an emergency back-up chamber;
• and
• an emergency magnet valve,
• wherein the emergency regulator valve is adapted to provide an output pressure nominally equal to a variable load pressure and at a tare back-up setting when the variable load pressure is lower than the tare back-up setting, and is coupled to a main relay regulator via direct connection between the main relay regulator and the emergency magnet valve,
• wherein the emergency magnet valve is controlled by a first electronic control unit that regulates brake cylinder pressure,
• wherein the emergency magnet valve is closed when energised,
• wherein, when the emergency magnet valve is de-energised, pressure is allowed into the emergency back-up chamber,
• wherein regulation of a brake cylinder pressure by the first electronic control unit continues during an emergency application such that the brake cylinder pressure applied during an emergency stop does not drop below a predetermined level, and
• wherein, in the event of power-loss during an emergency brake stop, a nominal emergency brake pressure is applied to the brake cylinders.