Release valve apparatus capable of being actuated by the vacuum that can be created in a main air line (1) for indirect air brakes of rail vehicles, comprising a release valve (12) in a connection (pipes 8, 9) from the brake control valve (3) to the brake cylinder (10). The release valve (12) contains a piston controlled two-way valve (24, 27, 28), which unblocks the passage in the off position of the release valve (12). In the actuated position, on the other hand, it blocks passage and vents the connecting segment (pipe 9) on the brake cylinder side. The piston (13) of the release valve (12) is loaded in the off position operating on a smaller piston area by main air line pressure, and by opposing pressure in an admission area (15) which is under atmospheric pressure in the off position and during the switching process to the operating position, and in this position is impacted by pressure in the connecting segment (pipe 8) leading to the brake control valve (3). The release valve apparatus assures switching back from the operating to the off position when the pressure rises again in the main air line only after the brake control valve (3) has been switched to its release position; the release valve apparatus is therefore capable of being used both for graduated air brakes and for direct-release air brakes without having to accept an unnecessary pressure loss.
An end of train railroad air hose having audible warning device which is powered by air from the air brake line and is actuated by the operator from the end of the train. The audible warning device may be located remotely from the operator via an elongated flexible conduit.
