Full-scale derailment tests on freight wagons

Abstract

Reducing derailments of freight trains is of utter importance for improving railway transportation since derailments lead to large service disruption, economic losses and risk related to transported goods. The present paper studies low-speed (below 30 km/h) derailment of freight trains, performing experimental full-scale tests, using an instrumented wagon equipped with a commercial derailment detector. Specifically, the dynamics of a freight wagon during wheel-climb derailment and the motion with one axle derailed are investigated. During the tests, accelerations were measured at the bogie and at the carbody. Moreover, the intervention of the derailment detector was monitored to assess possible causes of false tripping or miss-detections. Two loading conditions were analysed: empty and loaded wagon. Main achievements may be summarised as follows: (1) the activation of the derailment detector is always triggered by impacts between the axle-box and the rail; (2) if the wagon is empty, vibrations induced by a derailed axle over the sleepers strongly depend on vehicle speed and they may not trigger the derailment detector in the range 15–25 km/h; (3) derailment detectors must be installed at both ends of each wagon. This information may be used to develop derailment detection algorithms integrated into electric control units with computing capabilities..

KEYWORDS:

• Full-scale derailment test
• freight train
• derailment detector
• derailer

Acknowledgements

The authors kindly acknowledge the JRC (Joint Research Centre) Transportation for having funded this research project and all the other partners, especially the ones involved in the task.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Notes

1 Note that this is not the peak value measured during the tests. This result justifies the choice of the measurement range of the accelerometers: a lower measurement range would lead to a possible saturation of the signal; this compromises the measurement.

2 Similar considerations can be drawn considering the empty wagon test.

3 Readers are invited to view the videos supplied in the electronic version of the paper to have a clearer illustration of the derailment process.