On 6 May 2011, the trailing bogie on the 47th wagon of freight train 4PM6 derailed after traversing the Carlton Parade level crossing at Port Augusta, South Australia. The wagon travelled over a second level crossing and re-railed itself when it entered a third level crossing about 1,300 m later.
The train continued towards Adelaide before it was stopped at Winninowie after the network controller had been alerted that the train was emitting sparks and that the half-boom barriers remained down and that warning devices continued to operate at the two level crossings.
What the ATSB found
The ATSB’s investigation found a number of factors affecting the passage of train 4PM6 due to the degradation of the track geometry in a short section of line after the Carlton Parade level crossing. Multiple track defects requiring urgent and priority attention in this short section had been detected by a track geometry car inspection 3 months before the derailment and there was a 30 km/h temporary speed restriction (TSR) in force at the time. However, the defects had not been adequately assessed and controlled in accordance with the Australian Rail Track Corporation (ARTC) Track and Civil Code of Practice and the 30 km/h TSR was probably inadequate to minimise the risk of derailment.
The investigation also found that track geometry defect exceedence reports did not contain fields to record the date and time as confirmation that field inspections had been carried out in accordance with the Code of Practice.
What has been done as a result
The ARTC through its Alliance Partner Transfield Services has undertaken additional training in the ARTC Track and Civil Code of Practice. This includes the responses required when multiple localised geometric defects are found.
The ARTC is also developing an improved reporting format for data from the track geometry car measurements for use in all states following the introduction of the new National Code of Practice - Track Standards.
Multiple geometric track defects that are located in close proximity to each other significantly increase the derailment risk to rail traffic. The track condition should be thoroughly assessed and managed to ensure that appropriate speed restrictions are imposed until the track can be reinstated to design standards.