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Rolling stock managers at Pacific National have revised their maintenance and inspection procedures and engaged an independent consultant to review repair methodology after a structural crack in the underframe of a wagon resulted in a derailment.
On 20-21 April 2018, a Pacific National freight train was travelling from Melbourne via Adelaide to Perth. A short time after commencing the downhill grade from Mount Lofty to Belair, South Australia, the train derailed and eventually separated before both portions of the train came to a stop near Glenalta.
The ATSB found that a pre-existing structural crack in the underframe of a wagon likely expanded due to in-train forces, causing the platform's deck to bend and change angle. As the train negotiated a series of tight curves on the descending grade, a combination of wheel unloading and increased lateral forces resulted in derailment.
The ATSB found that multiple train examinations and maintenance inspections did not identify the crack, nor did Pacific National's inspection processes identify key structural points for inspection on wagons of the type that failed.
"This incident highlights the importance of rolling stock managers considering the key structural risk areas of their rollingstock and establishing guidance methods for ensuring that these risk areas are given an appropriate level of priority when undertaking inspections," said ATSB Director Transport Safety Dr Mike Walker.
As a result of the investigation, Pacific National altered its inspection and maintenance procedures to ensure that similar wagon types are less susceptible to this type of underframe failure, and that where detected, such cracks can be repaired.
You can find here the investigation report RO-2018-009: Derailment of freight train 6MP4 near Glenalta, South Australia on 21 April 2018
Last update 23 December 2020
