The Government has given approval for work on key Dublin Metro stations at the Mater hospital and the airport to begin ahead of the main Metro North contract.
Tenders for the work are to be published within months.
The aim of the early start is to avoid cross-over construction with a new hospital on the Mater site and with Terminal 2 at Dublin airport.
Minister for Transport Noel Dempsey said yesterday that exchequer funding would be used in advance of the public-private partnership contract to allow "enabling work" to begin immediately.
The decision is in response to fears in the Department of Transport that if the Railway Procurement Agency waited for the main contractor to build these stations, it would cause significant disruption at both the newly developed Mater and airport sites.
The Government believes that by giving the green light to the agency now, it will minimise disruption at both locations. "You can't tunnel under a 'live' hospital," a spokeswoman said.
The Railway Procurement Agency will now prepare a tender for the construction of the underground "station boxes". This is expected to be ready within months.
Work cannot get under way, however, until the agency receives a railway order from An Bord Pleanála. Last night the agency said it would be in a position to apply for such an order this autumn, with the hope of a positive outcome in 2009. According to Transport 21, Metro North is to open in 2012.
The Department of Transport has also revealed that the Government has now agreed the financing structure of the PPP in a move that allows the railway agency to proceed with the bidding process.
This week four international consortiums that have pre-qualified to tender for the Metro North project are to engage in a technical workshop, in advance of inviting them to bid formally for the project.
The metro and the green Luas line are designed to create a major new north-south rail route through the city. Critics have warned it will have a much larger catchment area than the existing Dart, while having less than two-thirds of the capacity.
The proposed route for Metro North will serve areas of Fingal where the population is expected to double in the next 20 years.
Dublin airport alone catered for 22 million passengers last year and Terminal 2 will facilitate growth to in excess of 30 million. The economic zone around the airport contains more than 14,000 employees. The metro will also serve other high-density centres such as Swords and Dublin City University.
Passenger traffic on Metro North is predicted to be 34 million in the first year of operation and the system will have capacity for 18,000-20,000 passengers an hour in each direction, based on 90-metre underground trams arriving every two minutes.
