Highway Construction and Albem Operations are set to build a major piece of BHP-funded road and rail infrastructure near Port Hedland.
That contract, worth $31.5 million, forms part of a $68 million project that will include construction of a 34-metre-long bridge over a nearby, BHP-owned rail line.
BHP will fund the bulk of the works, with the federal and state government kicking in about a third of funding.
Main Roads Western Australia will manage overall project delivery.
In a statement, the state government said the project would create 90 jobs during construction.
Works are due for completion in late 2022.
Premier Mark McGowan said the project would bring safety and economic benefits to Port Hedland.
“The three rail crossings carry a total of 6,000 vehicles per day, and providing bridges not only removes the risk of accidents, but eliminates the need for people to wait in their vehicles while long freight trains pass by,” he said.