13 July 2017
At about 1050 on 31 October 2015, Genesee & Wyoming Australia train 6DA2 derailed near Marla, South Australia. The derailment resulted from a package bearing failure on wagon FQWY 12-F. The wagon and three other container wagons were significantly damaged and there was significant damage to the track. There were no injuries.
The ATSB found that the journal and bearing on wagon FQWY 12-F had seized and lost interference fit. The loss of interference fit generated high levels of frictional heating between the bearing and the axle journal, and the subsequent torsional shearing failure of the axle (commonly referred as a ‘screwed journal’). The axle failure caused the axle and wheels to stop rotating, resulting in one wheel skidding along the railhead for approximately 50 km, before derailing.
On the balance of the available evidence, the ATSB concluded that a loss of lubrication was the most likely contributor to the bearing breakdown and seizure. Evidence also suggested the breakdown developed relatively rapidly, given the absence of a positive fault detection from two bearing acoustic monitoring systems (RailBAM) passed on the previous day of the occurrence.
Bearing failures leading to derailment continue to occur within the Australian
rail network. Rail operators must continue to be vigilant and ensure axle
bearings are correctly installed, maintained, and monitored throughout their
Investigation report: Derailment of freight train 6DA2 near Marla, South Australia on 31 October 2015