A commuter train derailed at the Sagamiko station on the JR East Chuo line in September 2013, the main cause being increased wheel load unbalance caused by an automatic air spring level controlling device damaged from human contact. The railcar had been used with the damage gone undetected, and where greater vertical force unbalance occurred on a transition curve, the wheel flange climbed on the rail and finally derailed.
Development of a System to Detect Malfunction by Monitoring of the Air Spring Pressure, H Fukuyama (Paper)
