Pneumatically piloted retainer valve for rail cars

A pneumatically piloted brake cylinder pressure retaining system, comprising:

• a retainer valve moveable between a release position where a source of brake cylinder pressure is connected to an exhaust and a bottle position where the source of brake cylinder pressure is isolated from the exhaust;
• a first pneumatic pilot for biasing the retainer valve from the release position to the bottle position;
• a first spring providing a first force biasing the retainer valve from the bottle position to the release position;
• a pilot valve moveable between a first position where a source of brake pipe pressure is provided via a first outlet directly to the pilot of the retainer valve and a second position where the source of brake pipe pressure is provided to the pilot of the retainer valve through a second outlet having a check valve with a predetermined cracking pressure;
• a second spring providing a second force biasing the pilot valve from the first position into the second position;
• and
• a second pilot for biasing the pilot valve from the second position to the first position that is connected to the first and second outlets of the pilot valve.