Discontinuation notice

Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the ATSB to discontinue an investigation into a transport safety matter at any time. Section 21 (3) of the TSI Act requires the ATSB to publish a statement setting out the reasons for discontinuing an investigation. This statement is published as a report in accordance with section 25 of the TSI Act, capturing information from the investigation up to the time of discontinuance.

Overview of the investigation

At 0415 Eastern Standard Time on 24 August 2020, a Pacific National containerised waste train, 1221, travelling from Clyde to Tarago, came to a stand near Lake Bathurst (248.400 km). Upon inspection, the train crew reported that the train had derailed the trailing wheels of the lead bogie of the 34^th wagon. The derailed wagon, RQEY1962D, suffered damage to the lead bogie and frame. The train had travelled approximately 2.7 km in a derailed state which resulted in damage to track infrastructure. There were no reported injuries to staff or members of the public.

John Holland Rail was the rail infrastructure manager for the line.

ATSB’s preliminary evidence collection revealed:

• A package unit bearing assembly on the R2 wheel of the trailing axle of the lead bogie of wagon RQEY1962D seized. After the seizure, the axle journal continued to rotate within the seized bearing as the wheelset rolled on. This caused significant frictional heat and wear of the journal which resulted in the journal shearing off and separating from the wheelset. This is known as a screwed journal. This caused the bogie to collapse under the 34th wagon.
• The remains of the failed bearing were inspected at Bearing Engineering Services at Auburn on 14 September 2020. The inspection found that the class D package unit bearing that had failed was effectively destroyed in the incident. The screwed journal section was not recovered from the derailment site however the outer ring and bearing adaptor were recovered from the bogie. The adapter, bearing cup, bearing cones, spacer, outer seal wear ring and cages were fused together and most bearing rollers were lost.
• An inspection of maintenance records found the bearing was previously reconditioned on 4 March 2019. Maintenance was completed on the wagon, bogie, wheelset and bearings as required by Pacific National’s wagon maintenance manual.
• There were no issues identified with the train management of train 1221.
• There were no identified track defects in the region approaching the derailment site.
• Wayside detectors that monitor wheel impacts and elevated bearing temperatures did not report impacts or temperatures above alarm limits. Immediately prior to the derailment at Burradoo the R2 bearing temperature was recorded as 60°C, 20°C higher than all other bearings on the wagon, this is below the alarm limit for warm bearings.

Reasons for the discontinuation

The ATSB considered the contributing factors to the derailment were a result of a failed bearing. The reasons for that failure were unable to be conclusively determined.

In response to the incident, Pacific National have proposed the following safety actions be initiated:

• Conduct a review of current Pacific National audit programs on bearing overhauler practices with respect to verifying that systems are in place to ensure correct grease quantities are applied to bearings.
• Conduct a review of current Pacific National audit programs on wheelset overhauler practices with respect to verifying systems are in place to ensure that axle journals are within the specified limits for diameter.
• Review the wagon maintenance manual (WMM 01-12) to determine if the impact levels and allowable response periods are appropriate to manage the risk of bearing failure for D class wheelsets.
• Develop data analytics capability to assess if combining the various wayside monitoring measurements could provide an improved insight into the risk of asset failure.

Based on this information, the ATSB considered it was very unlikely that further investigation would identify any systemic safety issues or identify opportunity for the enhancement of transport safety. Consequently, the ATSB has discontinued this investigation.

The ATSB is investigating the derailment of Pacific National operated freight service 1221 (loaded garbage waste train).

The train derailed in a John Holland Rail controlled network near Lake Bathurst (adjacent to Inveralochy Siding Road). The derailment site is located between Goulburn and Tarago, NSW.

A wheel bearing assembly of the trailing axle of the lead bogie of wagon RQEY1962D failed. This caused the trailing wheel/axle of the lead bogie to derail for a distance of approximately 2,500 m. There were no reported injuries to staff or members of the public. Wagon RQEY1962D suffered damage to the lead bogie and frame with minor damaged to track infrastructure.

This investigation is being led by the  NSW Office of Transport Safety Investigations (OTSI). OTSI conducts rail investigations in NSW on behalf of the ATSB under the Transport Safety Investigation Act 2003. Investigators have commenced collecting evidence from involved parties.

Should any safety critical information be discovered at any time during the investigation, the ATSB will immediately notify operators and regulators so appropriate and timely safety action can be taken.

A final report will be published at the conclusion of the investigation.