A three-firm consortium has signed a $2.4-billion contract to build 10 miles of twin tunnels on the planned 56-mile suburban rail loop around Melbourne, Australia. The first trains are scheduled to start running in 2035.

The new contract, between Cheltenham and Glen Waverley, covers the first part of suburban rail loop's 16-mile east section and starts construction on Victoria state's four-phase project, to be delivered over the next few decades.

CPB Contractors Pty Ltd, Ghella Pty Ltd and Acciona Construction Australia Pty Ltd. will start tunneling in 2026, using four tunnel boring machines (TBMs) powered by renewable electricity, according to the state. Work started last year on a 62-ft-deep TBM launch pit under a separate contract.

The two other teams, which were shortlisted for the first contract, are now competing for the remaining 6-mile east tunnel between Glen Waverley and Box Hill. 

Either John Holland Pty Ltd with Gamuda (Australia) Branch or Webuild S.p.A with GS Engineering and Construction Australia Pty Ltd are scheduled to secure the contract next year.

Melbourne's new orbital railroad is planned to loop around the city from Cheltenham, in the east, to Werribbe, in the west, passing through the airport.

The stretch between the airport and Sunshine has a 2029 completion target, while the final western section to Werribee is in early planning. The airport section is planned for completion in 2053. Both east and north stretches will be underground, while the rest will be at grade with elevated sections.