The Australian Transport Safety Bureau has concluded that a runaway train incident in Tasmania was caused by problems with its remote control system.
The train in question was a bulk cement carrier that “is operated as a driver-alone operation in a push-pull configuration with motive power provided from one locomotive.”
“To facilitate this push-pull configuration, a portable remote control system is used to control the locomotive,” the Bureau’s report states.
“The portable remote control system can be used both from outside of the train driver’s cabin during loading or unloading operations, and from within the leading driver’s cabin.”
But on September 21st, 2018, the remote failed.
“The driver was situated within the cement loading facility, and was remotely controlling the train to align wagons to the loading chutes,” the investigation report states.
“While the last pair of wagons were being aligned, the train came to a stop past the intended stop location.”
“The driver recalled that, at approximately 0842, he selected reverse to re-align the final two wagons with the loading chutes.
“However, after selecting reverse, the train became unresponsive to his remote commands.”
The driver “attempted multiple times to reset the remote control equipment with the portable remote transmitter. After allowing time for the remote control system to recover, the locomotive continued to be unresponsive to his commands.”
The driver therefore tried to board the train to reboot the remote control system, but before he could get aboard “the train slowly began rolling away towards Devonport”.
“The driver recalled trying to activate the emergency stop features of the remote system by removing power to the portable remote control system’s transmitter,” investigators said.
“However, the train did not respond to these commands and gradually gained speed as it rolled away from the loading facility.”
21km later, the train was routed into a dead-end siding, where it crashed. Two people were injured.
The Bureau has not yet figured out why the remote control failed. But TasRail has suspended all use of the remote control system from its operations, pending the conclusion of investigations.
It will be some time before the Bureau offers an opinion on exactly what happened: its initial report is the result of evidence collection. Examination and analysis of that evidence is yet to take place, and a draft final report is likely months in the future.