RO-2007-115

On Wednesday 7 November 2007, at about 0140, the trailing bogie of wagon UK10696, on Auckland to New Plymouth express freight Train 533, derailed at 103.848 kilometres (km) on the Stratford - Okahukura Line. The derailed wagon was dragged a further 2.75 km until the leading bogie also derailed.
The wagon tipped on its side, derailing the wagon immediately in front and behind it.
There were no injuries.
The cause of the derailment was not conclusively established, but the circumstances point to dynamic interaction between the track and the wagon, with the condition of both being at the upper limits of their working tolerances being a factor.
Safety issues identified included:
• recurrent derailments resulting from a combination of track geometry and wagon bogie condition at
or near current maintenance limits
• the quality and consistency of documented standards, rules and codes relating to the handling of
derailed wagons conveying liquid petroleum gas tanks
• the emergency response to the derailment.
Three safety recommendations have been made to the Chief Executive of the New Zealand Transport Agency to deal with these safety issues.