A runaway train laden with iron ore has been deliberately derailed by BHP after it travelled for more than 90 kilometres without a driver in WA's remote Pilbara region.

The Australian Transport Safety Bureau (ATSB) said the fully laden train, made up of four locomotives and 268 wagons, was travelling from the mining town of Newman to Port Hedland at 4:40am on Monday, when the driver hopped out to inspect a wagon near Hester siding.

But the train took off from the siding before the driver could get back on board.

It travelled 92 kilometres in about 50 minutes, until it was derailed at a set of points about 120 kilometres from Port Hedland.

That means the train reached average speeds of about 110 kilometres per hour.

BHP said the derailment was implemented from its Integrated Remote Operations Centre in Perth.

Staff at BHP's operations Centre in the Perth CBD executed the derailment. ( Supplied: BHP Billiton )

The centre controls the company's Pilbara operations, including rail and port facilities.

The ATSB has begun an investigation into the incident, and a spokesman said it was hoping to interview the train driver as soon as possible.

BHP said no-one was injured in the derailment and it had suspended all train operations while the investigation was carried out.

"We are working with the appropriate authorities to investigate the situation," a company spokesperson said in a statement.

Cost 'might register in millions': analyst

Business analyst Tim Treadgold said the derailment would not have a major effect on BHP's cashflow or share price.

BHP is counting the cost of the derailment and the disruption to its iron ore transport route. ( AAP: BHP )

"In the overall scheme of things, this is a very small event," he said.

"Even if they lost three days of access to the rail line, which is possible, it's not a major event.

"We're talking about a company that deals in the billions of dollars, and this might register in the millions, but almost certainly not in the tens of millions."

The incident comes amid a push for driverless train technology, with fellow miner Rio Tinto making its first autonomous iron ore delivery in July.

Three locomotives carried around 28,000 tonnes of iron ore over 280 kilometres from Rio Tinto's mining operations in Tom Price to the port of Cape Lambert.

The load was monitored remotely from Rio Tinto's Operations Centre in Perth, more than 1,500 kilometres away.