Workers sent to assist the driver of an iron ore train mistakenly went to the wrong train prior to a runaway and eventual derailment last November, the Australian Transport Safety Bureau (ATSB) has said.
A loaded train on BHP’s Pilbara railway reached 162km/h during its 91-kilometre runaway early on the morning of November 5, 2018.
To end the runaway, the mining company’s Perth-based control team forcibly derailed the train at a crossover 120 kilometres south of Port Hedland, destroying two locomotives, 245 ore cars, and two kilometres of track infrastructure. No injuries were reported.
The incident began when the train, heading north loaded with iron ore for export at Port Hedland, stopped 210 kilometres from its destination when communication between the lead locomotive and the combined end of train monitor was lost, triggering an automated 120 per cent ECP emergency brake application.
After radioing Hedland control, the driver placed the train’s reverser control to the centre (neutral) position, turned the generator field off and fully applied the locomotive independent brake before exiting the cab, according to a preliminary report released on Tuesday by the ATSB.
He was told via radio that due to the loaded nature of the train, and the track declining at 1.5 per cent, 101 per cent handbrakes were required to secure the train. He disembarked to begin applying the handbrakes to the train’s 268 ore cars.
Around the same time, personnel from the Redmont maintenance gang were sent to assist the driver. Roughly 30 minutes later, the Redmont gang told train control they had arrived at what at the time they thought was the train in question. It was suggested they begin applying handbrakes to ore cars starting from the back, working their way towards the driver, who was working from the front.
According to the ATSB report, the Redmont gang then began mistakenly applying handbrakes along the wrong train, an unloaded train on the southbound track; a train which had been stopped by the blocking protections set up by train control to protect the loaded train which needed attention.
Approximately 50 minutes after the loaded train had originally stopped, the driver – still alone – reportedly heard air venting from the ore car brakes, and shortly after noticed the train beginning to move forwards.
Drivers of nearby trains were ordered to stop and move to a safe place while the runaway took place.
BHP’s control team derailed the train by setting the crossovers at Turner South and Turner North to switch the train between adjacent tracks.
The train’s two head end locomotives entered the crossover at Turner South travelling at 144km/h. They, along with the first ore care, remained coupled and on track, travelling roughly 1.6 kilometres before stopping.
Ore cars in position 2 to 134 of the first rake, the pair of remote locomotives in the middle of the train, and ore cars 1 to 112 from the second unit rake derailed near the crossover. The remaining 22 ore cars of the second unit rake remained coupled and on track.
According to a statement published by Fairfax, BHP believes the mix-up by the Redmont gang was not a factor in the eventual runaway of the train. The mining company has blamed the incident on equipment failure and driver error.
“Our initial findings show that the emergency air brake for the entire train was not engaged as required by the relevant operating procedure,” a company spokesperson said in the fortnight after the incident. “In addition, the electric braking system that initially stopped the train, automatically released after one hour while the driver was still outside.”
The ATSB, which does not look to attribute blame through its investigations, said it is continuing to gather information ahead of a final report into the incident. A range of other factors will be investigated in coming months.