Abstract: A retaining valve includes an inlet and a valve member downstream from the inlet, wherein the valve member has first, second, and third positions. A first passage through the valve member allows fluid flow through the retaining valve when the valve member is in the first position. A second passage through the valve member allows fluid flow through the retaining valve when the valve member is in the second position. A third passage through the valve member allows fluid flow through the retaining valve when the valve member is in the third position. A slide moves with respect to the valve member in response to pressure at the inlet. A spring engaged with the slide biases the slide toward the inlet. A seal located at an axial midpoint of the slide prevents flow through the third passage when pressure at the inlet is less than a predetermined pressure.

Abstract: A brake cylinder pressure retainer valve device for a railway car having a "direct" exhaust position, a "slow direct" exhaust position, and a "high pressure" retention position. A cavity in the retainer valve body has a central pedestal on which a rotary type disc valve is mounted. The disc valve has different sized ports via which pressure is connected from an inlet port (in the retainer valve body) to an outlet port depending upon the position of a manually operated handle to which the disc valve is connected. One such port is associated with a spring loaded check valve to provide the "high pressure" retention of the brake cylinder exhaust pressure. A laterally flexible sidewall of the disc valve member is formed with 180.degree.

Abstract: A hold-back valve for single release air brakes includes a plug valve member in a chamber of a valve body and rotatable between at least two positions to establish paths of different resistance to flow between air inlet and outlet passages in the valve body. The plug has spherical central portion with a flattened surface and the spherical central portion is sealingly engageable with one end of a hollow cylindrical flexible packing surrounding the opening of the air inlet passage to the chamber in the valve body. The rotatable plug has passages therethrough to define two or three different flow paths when particular passages of the plug are connected between the air inlet and outlet of the valve body.