Jump to Content
Download final report
[ Download PDF: 2.43MB]
 
 
 

What happened

At about 0617 on 28 July 2017, a Bowmans Intermodal containerised ore train (1501S) travelling empty from Port Flat, South Australia (SA) stopped at Dry Creek South in SA. The driver felt the performance of the train ‘very sluggish’, as it was not rolling as it had prior to rounding a curve on the approach to Dry Creek South. The train crew notified the Australian Rail Track Corporation (ATRC) network control officer at Mile End, SA of their situation and that they intended to inspect their train. A short time later, the train crew confirmed to the network control officer that the last three wagons from 1501S had derailed. The train crew were uninjured. However, there was substantial damage to the wagons, track and signalling infrastructure.

What the ATSB found

The ATSB found a vertical split head defect had developed undetected from imperfections introduced during the manufacture of the rail 90 years ago. The defect propagated vertically and longitudinally, roughly through the centre line of the lower leg rail in the curve approaching Dry Creek South.

The passage of a previous train (1122) over this section of track caused an initial rail break, affecting the integrity of the rail and electrical continuity of the associated track circuit, which prevented a signal from clearing for the next train (1501S). The network control officer authorised the driver to pass the signal at stop, with the condition that the train travel at low speed.

However, the rail break was not visually obvious to the train crew as the locomotive rounded the curve. As the rear of that train passed over the break, a 2 m section of rail fragmented causing the last three wagons to derail.

Detailed (ultrasonic) inspection of the track about one month prior to the occurrence recorded a sustained loss of back wall echo at the derailment location, automatically marking the rail with a spray of paint. However, the ultrasonic inspection operator attributed the recorded event to the poor surface condition of the railhead, which is a common condition that can inhibit the testing. There was no retesting initiated or surface condition report lodged in response to the recorded event. The absence of any follow-up missed an opportunity to identify the presence of the vertical split head defect prior to the rail fracture and the subsequent derailment of 1501S.

What's been done as a result

Following the incident, Speno implemented a review of testing techniques used by operators where poor surface condition exists and the procedures for reporting and testing of rail affected by surface condition.

The Australian Rail Track Corporation reaffirmed the adequacy of the Track and Civil Code of Practice for ultrasonic inspections and the reporting requirements in accordance with contractual arrangements with the ultrasonic inspection operator. The rail in the Dry Creek area is programmed for replacement during 2018 as part of the Adelaide to Tarcoola Re-Railing Project.

Safety message

Defects can develop in rails (and welds) due to a wide range of reasons. Early detection and treatment of a defect that could cause a fracture of the rail is of major importance. While poor surface condition of the railhead is a known limit to the effectiveness of ultrasonic testing, its presence can mask internal track defects, particularly when the condition exists over an extended area. If an inspection cannot test or can only partly test rails, maintenance personnel must report the shortfall to highlight operational risk and the requirement for a timely supplementary examination.

Fractured rail section in lower rail of curve

Fractured rail section in lower rail of curve. Source:  ATSBSource:  ATSB

Download final report
[ Download PDF: 2.43MB]
 
 
 

The occurrence

Safety analysis

Findings

Safety actions

Sources and submissions

 
General details
Date: 28 July 2017 Investigation status: Completed 
Time: 0617 ACST Investigation phase: Final report: Dissemination 
Location   (show map):Dry Creek Investigation type: Occurrence Investigation 
State: South Australia Occurrence type: Derailment 
Release date: 31 October 2018  
Report status: Final Occurrence category: Incident 
 Highest injury level: None 
 
Train details
Line operator: Australian Rail Track Corporation (ARTC) 
Train operator: Bowman Rail 
Train registration: 1501S 
Type of operation: Freight train 
Sector: Freight 
Damage to train: Substantial 
Departure point:Pelican Point, SA
Destination:Bemax Siding, NSW
 
 
 
Share this page Provide feedback on this investigation
Last update 14 November 2018