When travelling at speeds near 90 km/h on track having particular track irregularities, the WOE class wagons appear to be susceptible to harmonic oscillations of sufficient magnitude to produce wheel unloading, flange climb and derailment.
At the time of this report release, the safety actions advised by Brookfield Rail and Aurizon had not yet been fully implemented.
In response to this safety issue, Brookfield Rail and/or Aurizon have advised of the following proactive safety action:
While the ATSB is satisfied that the actions proposed by Aurizon and Brookfield Rail will, when fully implemented, adequately address this safety issue, there remains a broad opportunity for rolling stock providers and rail transport operators to address the future risk associated with the development of resonant dynamic vehicle behaviours. The ATSB is therefore issuing the following Safety Advisory Notice.
The Australian Transport Safety Bureau encourages all rail rolling stock providers and rail transport operators to note the circumstances of the derailment outlined in this report and to consider the use of computer modelling, along with traditional field testing, in predicting the dynamic behaviour of rolling stock over combinational cyclic cross level/lateral track irregularities.
