What happened

On 11 July 2014, train ST24, a scheduled XPT passenger service, returning to Sydney Central Station from Melbourne Southern Cross Station, derailed at turnout MYD887 near North Melbourne station in Victoria. Turnout MYD887 was installed as part of the Regional Rail Link project. While certified for standard gauge revenue operations earlier that week, it had not been used by XPT services until the day of the derailment.

As a result of the derailment, there were minor injuries to some passengers and the train’s crew, as well as damage to track and rolling stock.

What the ATSB found

The ATSB found that the derailment of ST24 occurred at a type 37 mixed gauge turnout (MYD887), as the wheelset of a carriage (probably XAM2176) transitioned from the standard gauge short stock rail onto the broad gauge switch blade through the transfer area. It was determined that there were design deficiencies of the type 37 turnout with respect to transfer area width, guard rail protection, and capacity of the tie bar to resist elongation, that contributed to the derailment.

Earlier that morning the same train, travelling from Sydney as ST21, derailed at a similar type 37 mixed gauge turnout (MYD882) but re-railed a short distance later. The train crew felt the train bounce but were unaware that it had derailed, so continued into Southern Cross Station. The incident was reported to operational staff and the track was being inspected at the time ST24 derailed at turnout MYD887.

Post-derailment, an examination of the type-approved design of the type 37 turnout determined that it was lacking, in that it had been assumed that the type 37 turnouts would perform safely in service based solely on the performance of a similar (type 29) dual gauge turnout, although there were significant differences between the two turnout types.

The ATSB determined that there were no maintenance deficiencies with train ST24 that contributed to the derailment.

What's been done as a result

V/Line has actively managed the redesign, alteration and validation of the type 37 turnout, to support the safe operation of standard gauge rolling stock having wheel rim widths of 127 mm, including a comprehensive review of contractual arrangements, testing and commissioning processes.

Safety message

Proposed infrastructure changes, including those put forward by contractors, need to be thoroughly assessed at the design stage to ensure that they meet all operational and safety requirements.

Once constructed, infrastructure needs to be rigorously tested as part of the commissioning process to ensure that the changes are safe and perform to the original design intent.

On 11 July 2014, train ST21, a scheduled XPT passenger service, was travelling from Sydney to Melbourne. At Broadmeadows station (about 18 km north of the Melbourne CBD), a pilot boarded the train for the final part of the journey into Southern Cross station. The pilot was required to provide route familiarisation training for XPT drivers who were operating over the newly commissioned section of dual gauge track leading into and out of the Southern Cross station.

At about 0738, train ST21 entered the dual gauge ‘up’ fly over track and passed over MYD882 (dual gauge ‘up’ turnout), which was part of the newly commissioned track. As the train traversed the turnout, it bounced heavily. The pilot described it as ‘a short sharp dip in the track, similar to a short deep bog hole (mud hole)’ and explained that if the train hadn’t kept rolling, he would have thought they had derailed. The pilot immediately rang Southern Cross number 1 signal box and reported the occurrence. Number 1 signal box advised that they would arrange for a track inspection. The train continued into Southern Cross, where it was fuelled and joined by passengers and new crew, in readiness for the return journey to Sydney as train ST24.

At about 0830, train ST24 departed Southern Cross and travelled along the dual gauge ‘down’ fly over track on its journey towards Sydney. As the train approached signal MYD987, the driver observed a clear medium speed with ‘S’ indication. To the driver, this meant that the route was correctly set and that the train could traverse MYD887 (dual gauge ‘down’ turnout) at up to 25 km/h. As the train traversed the turnout at about 20 km/h, the driver and pilot felt several large jolts, followed by a series of fault indications on the driver’s display screen as the train came to a standstill. The pilot then rang the train controller and advised that train ST24 had derailed on the fly over. When the site was secured, the driver walked back to inspect the extent of the damage. Recovery personnel arrived shortly thereafter and commenced disembarking passengers.

Investigators from the ATSB and the Chief Investigator Transport Safety (CITS) Victoria attended the site and began gathering/protecting perishable evidence, including site data, photographs, measurements, CTC data logs and train data logs.

The investigation is continuing and will include an examination of the following:

• Design, quality control, commissioning and acceptance testing processes for dual gauge turnouts.
• The process for identification and examination of potential infrastructure or rolling stock defects that may result in derailment, following reports of suspected infrastructure irregularities.