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What happened

On 6 April 2016, Pacific National (PN) grain train 5422N parted at Parkville on the Main North Line. A fractured yoke on the trailing end of the fifth wagon allowed the yoke pin to fall out and the coupler shank to disengage from the wagon. The coupler shank fell into the four foot of the track and damaged the underbelly discharge doors on 10 wagons as the train progressed over the coupler. Approximately 10 tonnes of barley was released from the wagons as a result. The trailing wheelset on the thirteenth wagon was derailed, then ran in a derailed state for approximately 45 metres causing damage to several track sleepers before the train came to a stop. Regular services were able to continue under caution past the incident site via the adjacent crossing loop. Wagon recovery and track repairs was completed without any further incident.

What the ATSB found

A draftgear component (the yoke), that was not compliant with a PN maintenance standard, was not identified during a maintenance inspection and re-entered service undetected. The yoke was an earlier design and susceptible to fatigue failure. PN had identified the issue and completed a programme to replace this yoke design across their grain wagon fleet however, the yoke on this wagon had been overlooked.

What's been done as a result

PN issued an additional Rolling Stock Notice to their maintenance teams to advise of the incident and to mandate that all yokes in the grain wagon fleet were checked to ensure no yoke of this design remained in service.

Safety message

Maintenance systems must ensure that when a non-compliant component is identified as needing replacement, all such units are located and replaced.

Figure 1: 5422N at Parkville

Figure 1: 5422N at Parkville. Source: ATSB

Source: ATSB

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The occurrence


Safety analysis


Safety issues and actions

Sources and submissions



Safety issue

RO-2016-004-SI-01 -  

Preventative maintenance systems

The presence of the earlier design of yoke on wagon NGKF 35898X was not detected during preventative maintenance activities.

Safety issue details
Issue number:RO-2016-004-SI-01
Who it affects:Pacific National
Status:Adequately addressed

General details
Date: 06 April 2016 Investigation status: Completed 
Time: 0236 AEST Investigation phase: Final report: Dissemination 
Location   (show map):Parkville Investigation type: Occurrence Investigation 
State: New South Wales Occurrence type: Rolling Stock Irregularity 
Release date: 04 June 2018  
Report status: Final Occurrence category: Incident 
 Highest injury level: None 
Train details
Line operator: Australian Rail Track Corporation Ltd. (ARTC) 
Train operator: Pacific National 
Train registration: 5422N 
Type of operation: Bulk grain 
Sector: Freight 
Damage to train: Minor 
Departure point:Werris Creek, NSW
Destination:Carrington Grain, NSW
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Last update 04 June 2018