Travel detector for empty/load brake control

An empty/load brake control system mountable on a sprung and an unsprung member of a railway car and disposed between the car brake control valve and brake cylinder. Such system includes an empty/load sensor valve device (10) with an inlet passage connected to the brake control valve (60) and an outlet passage connected to the brake cylinder. It further includes a sensor arm (6) coupled to a sensor cable (12) whose movement is controlled by a sprung member (40) and a terminal member (42) disposed on an end of sensor cable, in contact with sprung member. A piston, under pressure, urges the sensor arm (6) to rotate and retract sensor cable but must overcome resistance of a spring. The system includes a load proportional valve (50) having a proportioning mode of operation when the valve device is in an empty setting and a non-proportioning mode of operation when the empty/load sensor valve is in load setting.