Executive summary
At approximately 0523 on 12 September 2006, the crew of the Pacific National hauled Patrick PortLink freight train number 2CM3 advised train control that their train had parted and the lead bogie of freight wagon CQBY 0130N had derailed.
There were no injuries as a result of the train parting or derailment and only minor damage to the track and rolling stock.
The investigation found that the draft key on the 'A' end of wagon CQBY 0118A had dislodged from the coupler shank allowing the coupler to withdraw from the draft pocket and fall onto the track. The dislodged coupler bounced under the train and derailed the wheel set of a trailing wagon.
Rectification work by the wagon owner to prevent a recurrence of this event includes the fitting of new drop forged steel retainer and locking pins to all wagons in the CQBY fleet.