The release device for multiple release compressed air brakes of railborne vehicles comprises a pressure reduction valve (12) which responds in the case of rapid brake applications and optionally of full brake applications, which in order to facilitate the brake release procedure and to accelerate the pressurization of the brake cylinder (13) feeds compressed air from the reference pressure chamber of the triple pressure control valve (2) into the brake cylinder (13). In addition, a sensor valve (25) is provided which, being monitored by an overflow valve (23) which only responds after at least full brake applications having been applied, is adapted to feed brake pressure from the brake cylinder (13) into the main air pipe (1). A feed valve (47) ensures in this context that any air supplementation from the air storage vessel (9) into the brake cylinder (13) through the triple pressure control valve (2) which is still in the brake application position, due to an interruption of that connection, is prevented; such air supplementation facility is not released by the feed valve (47) before the triple control valve 2 has been switched to its released position. The release device facilitates brake release and brake acceleration, in particular in the case of long trains, while saving air.
A pre-engagement unit for a braking pressure modulator for a pressure regulating circuit includes a first pneumatic inlet, a second pneumatic inlet, a first pneumatic output terminal, and a second pneumatic output terminal. The unit includes an electrically actuated valve system having a plurality of solenoid valves and a plurality of electrical terminals connected to output terminals of an electronic control unit. An electric braking command signal transmitter delivers a driver initiated electric brake value setting to an input of the electronic control unit. Under normal conditions, a supply pressure and a redundancy pressure are delivered at the first pneumatic output terminal to be converted by an air quantity augmenting relay valve to a braking pressure. In case of failure of the electronic braking system, the redundancy pressure is delivered at the first pneumatic output terminal to be converted by the air quantity augmenting relay valve to the braking pressure.
