| 摘要 |
A brake control valve device for a railway vehicle having a service valve piston assembly subject to a pressure differential between the brake pipe and a single reservoir acting on a first piston and to brake cylinder delivery pressure acting on a second piston of the assembly. A brake pipe reduction actuates the service valve assembly, toward service application position, in which position, the single reservoir pressure is connected to a pilot chamber of a brake cylinder exhaust control valve for actuating a brake cylinder exhaust valve to its closed position, while concurrently, connecting the single reservoir pressure to the car brake cylinders. Pressure limiting means is provided to assure that sufficient pressure remains in the single reservoir following a full service or overreduction application for the purpose of providing additional braking pressure during an emergency brake application. |
