A proposed multibillion transport project to connect Dublin Airport and Swords to the city centre is not expected to be completed until after 2030.

A new Metro North plan was one of six projects on a shortlist of options for the transport link, which was revealed by Minister for Transport Paschal Donohoe on Monday. About €165 million was invested in the original plan for Metro North before it was shelved in 2011 during the economic downturn, money that could be lost if the scheme is not chosen.

The other options include Dart links from Clongriffin, Maynooth railway line, a Luas line from Cabra through a tunnel under Glasnevin, a number of Bus Rapid Transit services and a combination of different transport services.

National Transport Authority chief executive Gerry Murphy told The Irish Times the design and planning stage would normally take about four years, before tendering and construction. “We want [the chosen project] in place in the early 2030s,” he said.

Mr Murphy said construction completion time was dependent on the scheme chosen and its complexity.

He added that it was not the last time the public would have a say in the process. However, he encouraged people to have a look at the plans before January 19th. “People should say what they think. The objective is to find the project that best meets the needs on a value-for-money basis of such an important area of the Dublin region.”

Scaled-back metro

Metro North’s scaled-back plan is from St Stephen’s Green to the airport and Swords, with an estimated cost of €2.8 billion, €460 million less than the original plan.

Savings would be made through having fewer Dart stations, smaller stations, and no tunnel through Ballymun (as the train line would be at surface level).

The Minister said the population growth estimate for the original plan was incorrect. “Metro North was clearly a project of its time. That’s why I’m so eager to have a process that will look at all of the options afresh.”

Mr Donohoe said the project would need to be decided on before he could identify where the money would come from to build the new transport links.

“We do remain in difficult financial circumstances,” he said. “It’s difficult to say at this stage; it depends what the project is going to be.”

Mr Donohoe said the Fingal area was one of the fastest growing areas in the country and the public transport needs of north Dublin were not being met.

To see the details on the full study go to nationaltransport.ie

Six proposals

Two heavy rail:

1. Dart link from Clongriffin to the airport and Swords (HR2): Projected cost: €790 million

2. Dartlink from the Maynooth Railway Line to the airport and Swords via a tunnel under Glasnevin (HR8). €2.1 billion

Two Luas/metro:

3. Luas line from Cabra to the airport and Swords via a tunnel under Glasnevin (LR3); €1billion

4. A metro proposal from St Stephen’s Green to the Airport and Swords (LR7); €2.86 billion

One Bus Rapid Transit (BRT) Option:

5. Combination of a number of proposed Bus Rapid Transit services (BRT 5); €330 million

One Combination Option:

6. Combination of a Dart link from Clongriffin to the airport and a Luas line from Cabra to Swords (C1). €1.3billion