By Matt O'Sullivan
The cost of a new metro rail line running mostly through tunnels between Sydney's CBD and Parramatta is set to exceed the $12.5 billion price of the railway soon to be built under Sydney harbour.
While insisting it was too early to put a figure on the cost of the proposed CBD-Parramatta line, Transport Minister Andrew Constance said it would be a "much bigger project" than the second stage of the government's current metro rail project.
That second stage requires digging twin tunnels between Chatswood and Sydenham, and then over-hauling the existing Bankstown Line, at an estimated cost of $11.5-$12.5 billion.
"It's a 25-kilometre tunnel between the CBD and Parramatta – and that's a twin tunnel – so that's potentially 50 kilometres of tunnel you are looking at," Mr Constance said of the Sydney Metro West project, which he wants built by the second half of next decade.
The new line from Sydney's CBD to Parramatta will be mostly underground.Credit: Geoff Jones
Mr Constance said the likely cost would be better known over the next 18 months as the project was fine tuned.
The number of stations on the line – likely to be between eight and 12 – will help determine the final price tag; a typical underground station can cost from $400 million to $500 million.
The tunnelling itself is relatively affordable. The tunnelling contract for the line between Chatswood and Sydenham, which includes demolition of buildings above station sites in the CBD and North Sydney, is $2.8 billion – less than a quarter of the overall cost of that metro project.
The government did not set aside any funding in the state budget this month for the new metro line, along which driverless, single-deck trains will run.
But it has said it will use funds from the sale of electricity company Ausgrid last year and value capture – placing levies on homes and other properties close to stations – to pay for the project.
Mr Constance said he expected contributions from value capture to amount to between 10 and 15 per cent of the capital cost.
The Bays Precinct near the inner-city suburb of Rozelle, and Olympic Park, have been named as "must have" locations for stations on the line. Passing loops will also be considered to ensure express trains are not hindered by all-stops services.
Sydney Metro director Rodd Staples said he was "open minded" about where in Sydney's CBD a new station for the line was built.
"Obviously there are some advantages of it going to Central [Station] but there are advantages for it going to Barangaroo or Martin Place," he said. "If it comes through the Bays Precinct it's more near the northern end of the city."
Councils such as Burwood's have been clamouring for stations to be built within their boundaries, while large property owners are eagerly awaiting the final route design because of the expected uplift in values it will bring.
Mr Constance said the new line was a "must build" because the existing T1 Western Line would reach full capacity by 2031, which "means quite literally you will not be able to get people physically onto the trains".
Meetings will be held over the next two weeks to canvass ideas about the project from industry and the wider community.
The government has left the way open for the line to eventually be extended westwards from Parramatta, as well as eastwards from Sydney's CBD.