Patent ID: 8919892

Claim:
A locomotive brake system comprising: a brake controller operable by an operator to generate brake signals and including an emergency output port which provides an operator emergency pneumatic signal on the emergency output port when the brake controller is in an emergency position; a brake valve responsive to brake signals from the brake controller for generating brake signals on a brake pipe; a brake pipe vent valve including a housing having brake pipe, emergency input and exhaust ports, a first valve that connects the brake pipe port to the exhaust port and opens in response to a greater pressure in a first volume than pressure in a second volume connected to the brake pipe port, the first and second volumes being connected by a choke and a second valve that connects the brake pipe port to the exhaust port and opens in response to a smaller pressure in a third volume connected to the emergency input port than pressure in a fourth volume connected to the brake pipe port; and the emergency output port on the brake controller being fluidly connected to the emergency input port of the brake pipe vent valve; wherein the first valve opens in response to the second valve being open and also in response to an emergency pressure in the brake pipe.