An axle bearing failure on a train wagon contributed to the derailment of a freight train near Hugh River in the Northern Territory on 23 December 2014.
The wagon, carrying distillate fuel, remained upright and there was some minor damage to the track (sleepers and rail clips). Fortunately, there were no injuries.
The ATSB found that the journal and bearing on the wagon seized and lost interference fit. This generated high levels of frictional heating between the bearing and axle journal, and the subsequent torsional shearing failure of the axle (a ‘screwed journal’). The axle failure immediately caused the leading axle of the trailing bogie to derail.
The ATSB concluded that a loss of lubrication or an internal bearing cage failure 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 day of the occurrence.
Safety message
Bearing failures leading to derailment continue to occur within the Australian rail network. Rail operators must continue to be vigilant and ensure axle bearings, and in particular axle box type bearings, are correctly installed, maintained and monitored throughout their life.
Read the report: Derailment of freight train 2AD1, near Hugh River, Northern Territory, on 23 December 2014