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.
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.