Detection of derailment of freight cars using mechanical contact sensors

In a long freight train, if some freight wagons derail away from the locomotive, there may be a delay in noticing the derailment. In such cases, there is a concern that the wagons may continue to run while derailed, causing significant damage to track components. Therefore, early detection of derailment is strongly required. On the other hand, it is difficult to apply the conventional derailment detection method with vibration acceleration sensors for passenger cars to freight wagons due to the specific characteristics of freight wagons. This is because freight wagons run in various conditions and on various tracks. Therefore, a derailment detection method with mechanical contact sensors has been investigated. The advantage of contact sensors is that derailment detection is easy to determine. Previous studies and findings have also indicated that specific parts of the bogies of freight wagons come in contact with other parts or rails during derailment. In this study, based on simulation results considering the results of previous studies, two suitable locations on the bogie were selected for the installation of the contact sensors. Furthermore, derailment tests were carried out on a real track by actually derailing a bogie with contact sensors installed and the detection performance was evaluated. The results showed that the contact sensors could detect the derailment immediately after it occurred.