The New South Wales (NSW) government in Australia will start the tender process later this month to build 15.5km of tunnels as part of the A$8bn ($7.96bn) North West Rail Link in Sydney, Australia.
The tunnels will be built between Bella Vista and Epping to allow trains to pass through them as first part of three phase project.
Over the next four years, the NSW government will invest A$3.3bn ($3.36bn), which the state government has earmarked in its budget, while the authority plans to spend A$360m ($367m) in this year alone.
The other phases of the project include surface construction works, rail systems, trains and operations, which the state government will float a tender for.
The North West Rail Link will be a 23km line, built along the outskirts of Sydney and will deliver eight proposed new stations and regular rail services.
Barry O'Farrell, NSW premier and minister for Western Sydney, said that the trains operating on the North West Rail Link would be a new generation of single deck vehicles, delivering a fast, safe and reliable journey for commuters.
"There will be no need for a timetable, customers will just turn up to one of the eight new stations proposed for the north-west and catch the next train," O'Farrell said.
According to NSW government, the single deck trains will run from Sydney's north-west to Chatswood every three minutes in peak times.
Construction work on the North West Rail Link is scheduled to begin later this year and the tunnelling work is on schedule to start in 2014.
As part of Sydney's Rail Future, the NSW government has announced that planning will start on a second heavy rail crossing of Sydney Harbour.
Upon completion, trains from the north-west will use the second harbour crossing to transport customers directly to the Sydney CBD via Chatswood and beyond.
In July 2011, an AECOM-led consortium had won a contract from the NSW government to plan and design the North West Rail Link.
The project will add six new stations and regular rail services to the CityRail network from Epping to Rouse Hill, in north-west Sydney, by linking the region with more than 300 other city rail stations.
Under the agreement, AECOM will deliver the planning, project definition, design definition, systems assurance, design concept approval, reference design, contract documentation and tender assessment phases.
The consortium also includes Parsons Brinckerhoff, Grimshaw Architects and Cox Architects.