Rio Tinto’s autonomous train network in the Pilbara has gained safety approval.

The Office of the National Rail Safety Regulator’s approval is the latest step in Rio’s bid to haul ore from pit to port autonomously by the end of this year.

Rio Tinto said in a statement that over 65 per cent of movements on its WA rail network have been completed autonomously, but it still has human drivers on board to monitor the trains and intervene in case of emergencies.

The miner says one train ran in full robot mode over a 100km distance.

The rollout of driverless trains on Rio’s entire 1,700 kilometres of rail will be completed in stages.

The budget for its ‘Autohaul’ project has climbed to more than $1 billion since it was initially announced in 2012.