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Rail fracture blamed for 2013 derailment

<span class="" id="parent-fieldname-description"> The August 2013 derailment of Pacific National freight train 9101 between Tempy and Bronzewing on the Mildura line in Victoria occurred due to fatigue in a mechanical rail joint according to the Australian Transport Safety Bureau (ATSB). </span> <div>Nine wagons located mid-consist derailed and separated from the consist with three wagons ending on their side during the incident. The train’s two locomotives, leading 21 wagons and final 10 wagons stayed on the track.<br /><br />There were no injuries to train crew in the incident. Around 300m of track was destroyed as a result of the incident.<br /><br />A recently-release ATSB report found that the cause of the derailment was the failure of mechanical rail joint.<br /><br />“The mechanical rail joint failed due to the development of fatigue cracks in both fishplates resulting in their subsequent overload fracture,” ATSB said.<br /><br />“The fatigue cracks had originated in the top surface of each fishplate and it is possible that differential sleeper support may have contributed to higher than normal cyclic tensile stress in the fishplates.”<br /><br />Lower than required fishbolt torque was also identified by the ATSB, and it was possible that movement within the joint may also have contributed to the development of the fatigue cracks, and the subsequent joint failure, the Bureau said.<br /><br />Fatigue cracks developed over a period of time and the overload fractures occurred prior to the passing of freight train 9101.<br /><br />“Movement of the separated rail ends during the passage of train 9101 resulted in a lateral discontinuity in the running rail at the joint and the train’s derailment,” the ATSB explained.<br /><br />Condition deterioration wasn’t detected by track inspections.<br /><br />“In the 27 months preceding the derailment, visual inspections of this section of track had been conducted solely from rail vehicles and track walking inspections had not been conducted at intervals specified by maintenance procedures,” according to the Bureau.<br /><br />As a result of the incident, V/Line has updated its maintenance system to generate automated work orders for track walking inspections.<br /><br />In order to improve the detection of track defects, maintenance staff have been provided with specific inspection criteria for track infrastructure including joints and fastenings in their work orders.<br /><br />“The implementation of effective inspection and maintenance regimes for the early detection and management of track defects is critical to the safety of rail operations,” the ATSB advised.