At about 0623 on 2 March 2013, Pacific National freight train 9501V, travelling from Appleton Dock to Tottenham Yard, derailed at South Dynon Junction near Melbourne, Victoria. Due to a track closure, the Network Control Officer (NCO) had been routeing all train movements via an alternative route through the South Dynon junction area via the North Dock line, signal DYN114, and 113 points. All of these train movements were standard-gauge trains. The NCO set the same route through South Dynon for train 9501V, a broad-gauge train. However, the route selected was for a standard-gauge train only as it did not contain a broad-gauge rail beyond signal DYN114, other than the 40-metre length leading to its truncation.
Having detected the train as broad-gauge and therefore incompatible with the remainder of the established route, the signal interlocking system prevented signal DYN114 from clearing. Train 9501V stopped at signal DYN114 and, through discussion, both the NCO and the locomotive crew assumed a signal failure. The NCO subsequently issued a verbal authority to the driver to pass signal DYN114. The locomotive crew then proceeded past signal DYN114 for a distance of about 40 m where the broad-gauge rail ended, resulting in train 9501V derailing at low speed.
What the ATSB found
The ATSB found that when the NCO established the route, the train control system provided no indication that sections of it were dual-gauge and sections were single-gauge. When train 9501V approached signal DYN114, there was minimal indication to the NCO that the train gauge and the selected route were incompatible. As the train proceeded past signal DYN114 and 113 points, it derailed because the configuration of the dual-gauge points assembly led to a truncated broad-gauge rail in the selected turnout direction.
The ATSB also found that there were deficiencies and ambiguity in the procedures for authorising movement past signals that display a Stop indication. There were also deficiencies in the route knowledge information provided to drivers and no additional indications to a train driver that the broad-gauge track terminated.
What's been done as a result
ARTC has modified the train control system to alert network control officers when a route is set that is not compatible with the gauge of the train, and has amended processes regarding authorising train movements past signals that are displaying a Stop indication.
This report emphasises the need for rail transport operators to provide adequately designed system displays that are not provocative of decision-making error by operators. It also highlights the need for train crew and NCOs to ensure they have considered the possibility that an unexpected Stop indication is not always due to signal failure.