Rail safety investigations & reports
Failure of wheel on locomotive near Fisher, SA on 28 May 2011
RO-2011-009
Summary
What happened
On Saturday 28 May 2011, intermodal freight train 5MP9 was travelling from Melbourne to Perth when one of its locomotives (SCT class) experienced a catastrophic wheel failure near Fisher, South Australia. The locomotive did not derail but sections of the broken wheel damaged a traction motor and associated components. The train travelled about 1976 m after the wheel failed and caused some sleeper damage and four breaks in the rail.
What the ATSB found
The investigation found that a fatigue crack had initiated at a small indentation on the inside of the wheel rim and then radiated towards the flange and tread regions before the wheel completely failed.
The rate of growth of the fatigue crack was influenced by high in-service mechanical loading of the wheel.
Inspection and measurement after the incident revealed that the locomotive wheel had sufficient rim, tread and flange thickness and was not worn beyond its service life, however it was likely the crack was present at a previous visual inspection and was not detected.
What’s been done as a result
The locomotive owner and maintenance provider has advised that they have implemented a revised program for more regular wheel re-profiling of its SCT class locomotive wheels to remove surface stressors in the wheel rim.
The locomotive maintenance program has also been enhanced to include a focus on visual inspections to detect impact damage to wheels and scheduled ultrasonic testing of locomotive wheels after mid-life is carried out when they are machined to detect cracks that may not be visible to the naked eye.
Safety message
Operators of locomotives that are exposed to high in-service mechanical loadings should be aware of the potential for wheel failure due to fatigue cracking and ensure inspection and maintenance programs include techniques for detecting and assessing wheel defects with the potential to lead to fatigue cracks.
Preliminary
Preliminary Report Release 9 October 2011
At about 0145 on Saturday 28 May 2011, intermodal freight train 5MP9 was travelling from Melbourne to Perth when it experienced a catastrophic failure of a locomotive wheel at about the 849.700track kilometre mark near Fisher, South Australia. There were no injuries. The locomotive did not derail but separated wheel fragments damaged the locomotive traction motor and associated components. The single-line track incurred four rail breaks and broken sleepers over a distance of about 1 km.
Photo
To download, click the link, then right-click and select Save As.
Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations and should be credited accordingly.
Safety Issues
Wheel inspection processes
The wheel inspection processes prior to the failure of locomotive wheel L4 on SCT 008 were not effective in detecting surface damage or cracks
| Issue number: | RO-2011-009-SI-01 |
|---|---|
| Who it affects: | Rail Rolling stock owners, operators and maintainers |
| Status: | Adequately addressed |
Class BM Steel prone to subsurface Cracks
Subsurface cracks appeared to be more common on wheels made with Class BM grade steel while operating under conditions of high speed cyclic loading, such as the SCT class locomotives
| Issue number: | RO-2011-009-SI-02 |
|---|---|
| Who it affects: | Rail Rolling stock owners, operators and maintainers |
| Status: | Adequately addressed |
General details
| Date: | 28 May 2011 | Investigation status: | Completed | ||
| Time: | 0145 CST | Investigation level: | Systemic - click for an explanation of investigation levels | ||
| Location (show map): | near Fisher | ||||
| State: | South Australia | ||||
| Release date: | 03 July 2013 | Occurrence category: | Incident | ||
| Report status: | Final | Highest injury level: | None |
Train details
| Train registration | 5MP9 | |
|---|---|---|
| Type of operation | Freight train | |
| Damage to train | Minor | |
| Departure point | Melbourne, Vic. | |
| Destination | Perth, WA |