A runaway driverless freight train that derailed in northern Tasmania and injured two people ignored commands before rolling away from a loading facility, a report has found.
The out-of-control 1132-tonne TasRail train was deliberately derailed by authorities on September 21 near the heart of Devonport.
It was being loaded with cement 21 kilometres away at Railton when it became unresponsive to the driver's remote control system, preliminary investigations released on Friday by the Australian Transport Safety Bureau found.
The driver put the train in reverse to line up its final two wagons with loading chutes, but it then became unresponsive.
He tried to reset the remote control system several times to no avail.
As the driver walked to the train to restart the system, it began to slowly roll downhill.
He then tried to activate emergency stop features but the train didn't respond.
The driver reported the runaway train to TasRail Train Control, who called emergency services.
Police were forced to stop traffic at level crossings and warn people of the oncoming 220-metre long train as it sped on without a driver towards Devonport.
The train, loaded with cement, hit a concrete footing and wooden fence at the city's waterfront at 9.09am, nearly half an hour after becoming unresponsive.
A man and a woman were struck by flying debris and suffered cuts and abrasions.
The freight train and eight wagons were significantly damaged.
The train regularly operated between Railton and an unloading facility in Devonport.
TasRail has suspended all use of remote control systems pending final conclusions of the ATSB investigation.