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What happened

On 2 December 2015, BHP Billiton (BHPB) train M03544 was loaded with iron ore at Yandi, Western Australia (WA). The train departed Yandi at about 2211 Western Standard Time (WST) and travelled north towards Port Hedland, WA, on the Newman main line.

At about 0530 on 3 December 2015, the train controller based in Perth was alerted to a dragging equipment detector (DED) alarm at the 67 km mark at Walla. Seven seconds later, train M03544 recorded a loss of brake pipe air pressure before the train came to a stop with the lead locomotive positioned near the 64.188 km mark, about 3 km from the DED.

The train controller contacted the train driver, advising that DED alarms had activated on both the east and west tracks. The train driver informed the controller that a loss of brake pipe air pressure had resulted in an uncommanded brake application bringing the train to a stop.

Shortly afterwards, as the driver walked towards the rear of the train to determine the cause of the loss of air pressure, he found that the train had separated and derailed.

What the ATSB found

The ATSB investigation identified that train M03544 derailed due to a broken rail. A fracture of the rail was probably initiated by the rapid growth of a detectable, yet unidentified, fatigue‑related transverse defect(s) in the west rail near the 67 km mark during the passage of the train.

The investigation also identified that the condition of the rail in the vicinity of the fracture contributed to relatively frequent failures in that area.

Finally, ultrasonic defect testing of the rail was undertaken in the heat of the day, potentially masking defects due to compressive forces in the rail.

What's been done as a result

In response to this occurrence, the operator of the train and track, BHP Billiton, took measures to improve track condition and reduce in-service rail defects by:

  • accelerating the re-railing of 833 kilometres of track, including replacement of the track in the vicinity of the fracture
  • the introduction of processes to:
    • reduce the initiation of rolling contact fatigue cracks in rail track
    • improve rail defect detection to prevent fatigue cracks from progressing to track failure.

Safety message

Early detection, assessment, and effective management of track defects is critical to minimising the risk of derailment and maintaining safe rail operations. Therefore, it is essential that track maintenance and infrastructure fault detection be of a high standard.

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[ Download PDF: 1.75MB]

The occurrence


Safety analysis


Safety issues and actions

Sources and submissions


Safety issue

RO-2015-023-SI-01 -  

Rail condition

The general condition of the rail on the west track, in the vicinity of the rail fracture, contributed to relatively frequent failures in that area.

Safety issue details
Issue number:RO-2015-023-SI-01
Who it affects:Users of the affected rail track
Status:Adequately addressed

General details
Date: 12 March 2015 Investigation status: Completed 
Time: 0525 WST Investigation phase: Final report: Dissemination 
Location   (show map):near Walla Investigation type: Occurrence Investigation 
State: Western Australia Occurrence type: Derailment 
Release date: 12 October 2018  
Report status: Final Occurrence category: Serious Incident 
 Highest injury level: None 
Train details
Line operator: BHP Billiton 
Train operator: BHP Billiton Iron Ore 
Train registration: M03544 
Type of operation: Freight 
Sector: Freight 
Damage to train: Substantial 
Departure point:Yandi, WA
Destination:Port Hedland, WA
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Last update 14 November 2018