Abstract: A system for indicating whether a hydraulic--pneumatic cushioning unit mounted on a railway car to cushion impacts contains sufficient hydraulic fluid to cushion impacts includes a signal assembly mounted on the body of the cushioning device, the signal assembly unit including a pressure indicator and a signal unit which is removably mounted on the pressure indicator. A cable connects the signal unit to a radio mounted on the railway car. An actuator in the pressure indicator moves when sufficient hydraulic fluid is lost from the cushioning device to impair the ability of the device to cushion shocks. Movement of the actuator operates a switch or load cell in the assembly to send a signal through the cable to the radio which then broad-casts a signal indicating that the cushioning unit is inoperative.