Overloads are mainly installed at formation stations, section stations, and entry and exit signal locations at stations with cargo inspection operations. Used to determine if a railroad car is overloaded and off-loaded. It is an important equipment for the National Railway Group to control the safety of railway freight. The product is divided into normal over-deflection load applicable to trains of 60km/h and high speed over-deflection load of 100km/h. The over- and off-load detection device is mainly for monitoring and warning the over-weight, off-weight and off-load loading status of key cargoes (such as: coiled steel, glass, alumina, heavy rail, etc.) that are prone to tumbling, breaking, collapsing and crosstalk during railway wagon transportation, to prevent and eliminate to freight safety belt.