Method of estimating the probability of derailment during an earthquake using the seismic waveform

Abstract

This paper describes a methodology for probability estimation of derailment occurrence due to an earthquake by the use of seismic waveforms. Under the method proposed, an index for probability estimation of derailment is calculated using the estimated or measured seismic waveform of a track and the three types of running safety limit of the target railway vehicle to sinusoidal vibrations of tracks. The index is calibrated using dynamic simulations of the vehicle behavior with various seismic vibrations in order to obtain the relation between the value of the index and the derailment probability. The dynamic simulations can be executed previously. Therefore, when the seismic vibration of the track is obtained, the time to estimate probability of derailment using the method proposed is much shorter than using dynamic simulation of vehicle behavior. In the case of the Sinkansen train dealt with in the design standard of railway structures, if the calculated index is equal to 10, it means that the probability of derailment occurrence is about 50 %. If the index is larger than 30, the train running on the seismically vibrating track certainly derails due to the earthquake. The method is applicable to the following cases; (a) Quick extraction of sections with high probability of derailment occurrence from the whole train line, and support for the restoration of derailments in the event of a large earthquake. (b) Quantitative check of the effect of seismic countermeasures taken of the railway vehicles, tracks and structures from the standpoint of derailment occurrence probability.

Keywords

• railway vehicle
• earthquake
• running safety
• seismic vibration of track
• probability of derailment
• evaluation of a whole rail line