Final Report


What happened

On 24 July 2015, container freight train 6MC2 lost two containers from the train as it passed through Bowser, north of Wangaratta. The two containers lost from the train landed clear of the track on the eastern side. The train continued its journey with the crew unaware of the incident.

At about 0430 the following morning, the driver of another freight train noticed a container and reported it to train control.

What the ATSB found

The ATSB found that it was very likely that the twist locks that secured the containers to the train were ineffective prior to the incident. This condition allowed the unsecured containers to fall from the train. It is probable that strong winds contributed to the movement of the unsecured containers. Other external forces, such as train and track dynamics, may have also contributed to the movement. However, there was no evidence of such contribution.

Given the containers were located some distance behind the locomotives, and that no other train operational systems were affected when they fell from their respective wagons, the train crew were not aware of the incident.

What's been done as a result

As a result of the incident, Pacific National undertook an internal investigation into the incident and has taken action to:

  • initiate a process to include checks for twist lock operation as part of wagon maintenance and inspection
  • develop a twist lock inspection manual
  • update freight loading manuals to include methodology for identifying defective twist locks
  • update wagon maintenance manual to include methodology for identifying defective twist locks
  • update twist lock training materials to include identification of defective twist locks
  • initiate a review of twist lock integrity history
  • initiate a review of twist locks currently in service – supply and type
  • calculate the failure rate of twist locks across the Intermodal fleet for probability and risk mitigation considerations.

Safety message

Rail operators should satisfy themselves that their procedures can ensure that all twist locks are effective at securing freight containers to their respective wagons before the transit of trains.

The occurrence

Safety analysis

Safety actions