A system for maintaining brake cylinder pressure includes a brake cylinder passage configured to be in fluid communication with a brake cylinder, a brake pipe passage configured to be in fluid communication with a brake pipe and a brake cylinder, a first valve member moveable between a first position and a second position, and a second valve member in fluid communication with a reference pressure. The second valve member is configured to move the first valve member from the first position to the second position based on a differential between a pressure within the brake cylinder passage and the reference pressure, where the brake pipe passage is configured to only supply air from a brake pipe to a brake cylinder when the first valve member is in the second position.