Running Safety of Railway Vehicle as Earthquake Occurs

Takefumi MIYAMOTO Researcher, Vehicle Dynamics Lab., Fundamental Research Department
Hiroaki ISHIDA Manager, Vehicle Dynamics Lab., Fundamental Research Department
Masaki MATSUO Senior Chief Engineer, Engineer Dept., TESS Co. Ltd.

We have studied the dynamic behavior of railway vehicles on track vibrated due to earthquake etc., by using numerical simulations. We developed a new simulation program which is adapted to a large displacement as the railway vehicle does, i.e., derailment or overturn. The dynamic behavior of vehicle was analyzed as the track was vibrated in the lateral and vertical directions by using the new simulation. We proposed the tentative running safety limits corresponding to the frequency response of the vehicle system which runs on vibrating track, that show the critical amplitude of track vibration at each frequency. The influence of vertical vibration added to lateral vibration on these running safety limits is investigated.
As a result, it is found that the lateral vibration is dominant in the vehicle behavior near the running safety limit, although the vertical track vibration promotes jumping of wheels. In the low frequency area, the rolling motion of the carbody is excited gradually, and then the vehicle overturns when the amplitude of track vibration exceeds the running safety limits. In this case, the displacement of track is large, but the acceleration of lateral track vibration is comparatively small. In the high frequency area, the wheel flange comes into collision with the rail in a few number of vibration, and it causes jumping of wheels and a derailment, and the acceleration of lateral track vibration at the running safety limit is comparatively large.