Abstract: A derailment detector for a railway vehicle includes a housing in selective fluid communication with a brake pipe of the railway vehicle to receive compressed air from a pneumatic braking system. A main chamber is disposed within the housing and pressurized by the compressed air. A shock detection assembly is adapted for detecting an acceleration indicative of a derailment condition and activating a main valve disposed within the main chamber upon detection of the acceleration indicative of the derailment condition. A discharge valve is in selective fluid communication with the main chamber, where, upon detection of the acceleration indicative of the derailment condition, the discharge valve is operative for discharging a predetermined amount of the compressed air from the main chamber to indicate that the derailment condition has occurred.

Abstract: Improvements in devices designed to actuate the air brakes of a freight car when a derailment occurs; a device which operates to immediately detect a wheel derailment of a railway train and automatically brings the air brake system of the train into a state of emergency stop; a fail open system and apparatus including an air relief valve attached to a railway car and also connected to the air brake pipe of the air brake system, sensor cylinder and spring assemblies connected to the railroad car body at one end thereof and at the other end to the side frame of a railroad car truck adjacent the railroad car wheels, an oil reservoir in the air relief valve which, when full, maintains the air relief valve closed and not venting air from the air brake pipe, a piston with an elongate piston rod associated with an oil reservoir in each sensor cylinder, the end of the piston rod being attached to the truck side frame, a line communicating between the oil reservoirs of the air relief valve and each sensor cylinder so

Abstract: In order to detect derailment of a railway vehicle each vehicle in a train is provided with an acceleration responsive device which, in response to the vehicle acceleration resulting from derailment of the vehicle transmits a short range radio signal to a receiver installed in the engine to provide a visual or audio alarm. In one practical arrangement requiring no routine maintenance each transmitter unit has a resonant circuit which is energized as a result of the stressing of a piezo-electric crystal upon vehicle derailment, avoiding the need for any separate electrical power source on the vehicle.