Measures to Prevent Accidents Such as Derailments at the Sagamiko station 

A commuter train derailed at the Sagamiko station on the JR East Chuo line in 2013, due mainly to increased wheel load imbalance caused by an automatic air spring level controlling device that had been damaged in an accident caused by a person on the tracks. The railcar had continued use with the damage undetected and the damaged automatic air spring level controlling device caused one corner of the car to be pushed up into an abnormal position.

To detect increased wheel load unbalance caused by malfunctions in air spring devices, we developed a system to detect malfunctions by monitoring the pressure and implemented it on JR East’s newer models.

We also devised a method to detect excess wheel load imbalance through the wheel load measured in passing trains using a strain gauge attached to the rails. We developed a system for detecting excess wheel load imbalance using this detection method and started trials by prototype with a view to implementation.