The NEWest Alliance will deliver the Yanchep Rail Extension and the Thornlie – Cockburn Link, which have a combined budget of AU$1.056bn (£558m).
The alliance-style contract is funded by the Western Australian and Australian governments. Revenue to each contractor will be confirmed at contract execution.
The Yanchep Rail Extension extends the Joondalup line north from Butler to Yanchep and involves the construction of three new stations to support the area’s growing population.
The Thornlie – Cockburn Link connects the Mandurah and Armadale lines and involves the construction of two new stations and improved public transport services to the city’s southern suburbs.
CPB Contractors managing director Juan Santamaria said: “CPB Contractors is proud to be playing this key role in the landmark Metronet project and to support the ongoing development of Perth as a vibrant, world-class city.”
Downer chief executive officer Grant Fenn said: “We look forward to working with our partners to deliver this important project for the Western Australian government and the people of Perth.”
Work on the project is due to start this year and is scheduled to be completed in 2023.