Final Report


What happened

On 9 November 2015, Pacific National train 9150 was travelling from Carwarp in north-western Victoria to Melbourne. The train consisted of two locomotives and 20 wagons, of which 19 were loaded with grain.

At about 1532, the train was travelling through Nunga, 8 km south of Ouyen, at about 80 km/h. The train had almost cleared the Janiels Road level crossing when the trailing bogie of the last wagon derailed. The train was brought to a stand about 1,400 m beyond the crossing with no injuries. The track sustained damage from the derailed wagon.

What the ATSB found

The ATSB found that the derailment was a result of the track buckling during the passage of train 9150. Instability in the track was the result of the rails creeping over time and bunching at the crossing, increasing their vulnerability to lateral misalignment in the hot conditions of that day.

It was found that the asset management systems used to identify problematic levels of rail creep (the longitudinal movement of rail over time) did not incorporate algorithms to flag creep that had accumulated over an extended period. There was a reliance on these systems by track maintenance staff, and in the absence of flags for the identification of cumulative creep, the potential for lateral instability at this location was not identified. General inspections did not provide an effective supplementary means of detecting the potential instability.

It was also found that creep management procedures did not ensure that creep defects were identified and managed in a timely manner and prior to the onset of hot weather.

What's been done as a result

V/Line has updated the network standard for the inspection and assessment of lateral stability. It has also included algorithms within the asset management system for the accurate assessment and generation of remediation work orders for cumulative creep, and to correct for fixed points within track, such as level crossings.

In addition, V/Line has amended its procedures to include a requirement to assess and correct rail creep prior to 1 November each year.

Safety message

Asset management systems that provide the primary triggers for rail creep management should consider all criteria that can affect the creep condition and ensure corrective action prior to the onset of extreme weather conditions.

The occurrence


Safety analysis


Safety issues and actions

Sources and submissions