This will be the first industrial action at Rio's Pilbara operations in Western Australia since 1992.
A Rio spokesman said the company had received a notice of protected action, providing the three days notice required under the federal Workplace Relations Act.
The document indicated that train drivers would stop work for 12 hours, commencing midnight on Friday, he said.
The action could continue beyond Saturday in a series of work stoppages, Construction Forestry Mining and Energy Union (CFMEU) mining division secretary Gary Wood said.
Wood said Rio's 39 train drivers, CFMEU members, voted unanimously in favour of the 12 hour stoppage at a meeting in Perth last night.
They had also "endorsed a campaign of action" at the meeting but would wait for Rio's response to Saturday's stoppage before deciding on further action, he said.
The drivers are seeking an annual pay rise of 4.75 per cent, plus $20,000 a year for employees affected by Rio's plan to introduce driverless trains at its Pilbara operations by 2012.
Rio announced the ambitious automation plan in January.
Its Pilbara mines would be controlled from a new centre in Perth, about 1,300 kilometres from the miner's railways.
Wood said a 4.75 per cent salary increase was in line with consumer price index (CPI) adjustments to the end of June.
Train drivers faced a $20,000 reduction in earnings if Rio moved to driverless trains on its main rail line to the Dampier Port, leaving them with only guard work, he said.
The union wants this amount added to the train drivers' base salary.
"Clearly, the workforce believe it is time for a change," Wood said.
"The claim that has been put forward by the union is in the form of a modern, flexible agreement that delivers for both parties."
The Rio spokesman said he hoped the action could be avoided.
"We continue to talk to all workers, as we did before," he said.
"We have been directly engaged with our staff since 1992 and not lost a day to industrial dispute since then."
Wood said the industrial action would affect Rio's iron ore output, but some trains would still run to Cape Lambert and from Pannawonica.
However, the Rio spokesman said any talk of the impact of the action "was purely hypothetical".
