Rolling Stock Irregularity

At about 1802 on 1 August 2012, XPT passenger train ST23 (Sydney to Melbourne) reported loss of air shortly after traversing a level crossing between Longwood and Seymour in Victoria. Initial advice indicated that the coupler between the lead locomotive and adjoining passenger car had failed which led to the brake line and other service connections being damaged.

Discontinuation:

Section 21 (2) of the Transport Safety Investigation Act 2003 (TSI Act) empowers the Australian Transport Safety Bureau (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.

On 1 August 2012, the ATSB commenced an investigation into a separation of train ST23 at 1802 Eastern Standard Time on 1 August 2012 near Seymour, Victoria. Examination of the information collected during the investigation identified that the occurrence had significant similarities to the investigation of the partial separation of train ST24 near Broadmeadows on 11 August 2011 (RO-2011-012). 

Accordingly the ATSB decided to examine the Seymour occurrence as part of the Broadmeadows investigation (RO-2011-012) and therefore investigation RO-2012-008 was discontinued.

Safety summary

What happened

On 11 August 2011, a scheduled Melbourne to Sydney Express Passenger Train (XPT) partially separated as it passed over a dip in the track near Broadmeadows, Victoria. The train suffered a total loss of power and was unable to continue its journey.

What the ATSB found

The ATSB found that the tail pin in the draft gear between the lead power car and first carriage failed as a result of a brittle overstress fracture that was initiated by fatigue cracking. Recent routine ultrasonic testing had not detected the presence of the fatigue crack and post incident material testing established that the mechanical properties of the tail pin were below the required standard.

Following this incident, the ultrasonic testing procedure was revised to improve the detection of smaller cracks in the tail pin. However, the separation of another XPT near Seymour, Victoria, on 1 August 2012 in similar circumstances highlighted the fact that the ultrasonic testing regime was still not detecting all small fatigue cracks in critical areas of the tail pin.

This investigation did not examine how the track irregularities near Broadmeadow may have contributed to the partial separation of train ST24, why the track condition deteriorated significantly in the 6 weeks between when it was last rehabilitated and the day of the partial separation or why the inspection and maintenance regimes in place at the time did not detect the deterioration in track conditions. These issues will be considered as part of the broader safety issue investigation RI-2011-015 Safety of rail operations on the interstate rail line between Melbourne and Sydney.

What's been done as a result

A new batch of tail pins has been manufactured to an upgraded standard which includes improved quality control and acceptance testing and RailCorp, the operator of the XPT fleet, is currently in the process of fitting these new tail pins. RailCorp has also further revised the tail pin inspection regime with the aim of improving its effectiveness.

Safety message

It is important that components are fit for purpose and meet the appropriate requirements for service and that inspection regimes are effective in providing assurance of continuing equipment reliability.
 

Preliminary report released 9 October 2011

This preliminary report details factual information established in the investigation’s early evidence collection phase and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

Abstract

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.

Abstract

At about 2031 on Wednesday 30 March 2011 a southbound Port Kembla to Parkes empty bulk grain train experienced a train parting event at about the 285-track kilometre point near Gunning (Oolong), NSW, on the down main Sydney to Melbourne rail line. There were no injuries or damage as a result of the incident.

Overview

At about 1856 on 24 January 2010 a loaded freight train designated 2224, travelling from Medway Junction to Berrima Junction, derailed one bogie on the second-last wagon at Exeter, NSW.

It was determined that wagon NPZH 35700U derailed due to a 'screwed journal' as a result of a wheel bearing failure. As the bearing failed, it generated and transmitted sufficient heat to the axle journal, to make it 'plastic' and allow the end carrying the failed roller bearing assembly to 'screw off'.

There was insufficient evidence to determine the cause of the bearing failure.

The investigation identified two safety issues in relation to:

• the in-service condition monitoring of the wheel bearing which was ineffective in detecting the failing bearing before it led to the derailment, and,
• bulk hopper wagons loaded with limestone which have been regularly operated at speeds up to 15 km/h higher than the mandated limit for some classes of track.

In both cases the train operator has taken safety action to address the issue.