The placement of three empty rollingstock platforms immediately behind the locomotive was one of a number of key factors that combined to cause a freight train to derail at Glenalta, South Australia on 21 November 2004, according to an ATSB investigation report released today.
The Australian Transport Safety Bureau report states that the accident occurred after a single freight wagon bogie derailed over a set of points at Belair. A wheel contacted and lifted on top of a check-rail. The check-rail is designed to guide a wheel in the correct direction through the points. However, in this case the wheel was no longer retained by the check-rail and it travelled in the wrong direction subsequently derailing. No one was hurt as a result of the derailment. There was extensive damage to property, both public and private.
The ATSB engaged experts in advanced rail simulation modelling to test the hypothesis that the marshalling of the train and the placement of the empty platforms was the major factor in the derailment. The simulation provided compelling data to suggest that the weight configuration of the train was not of itself sufficient to cause the derailment. Other factors such as braking in such a way that compressive forces were accentuated, the suspension of the empty platforms, and a track geometry which resulted in wheel oscillation, also combined to induce the derailment.
The crew was not immediately aware that a bogie had derailed, and the freight train continued for 3.7 km, progressively derailing other bogies before the derailment became apparent. The locomotive drivers realised that some wagons had derailed as the train reached Glenalta and immediately applied braking. The train finally stopped some 200m beyond the Glenalta railway station. A total of 10 freight wagons were derailed, with five obstructing TransAdelaide's passenger line and four coming to rest down an embankment into private residential properties.
While the report concludes that safety actions implemented immediately following the derailment are likely to have prevented any similar accidents, the investigation identified further opportunities to improve railway operational safety and made seven safety recommendations.