The Government is considering a revised metro system to run between Dublin city centre and the airport and Swords in north county Dublin.

The metro plan, which would run from St Stephen’s Green, had appeared to have been effectively killed off on cost grounds a number of years ago. However, it is understood a revised, less expensive “optimised” metro system has now been proposed to Minister for Transport Paschal Donohoe by the National Transport Authority (NTA) following an assessment of the transport requirements of Fingal and north Dublin.

A number of sources said the metro has emerged as the preferred option, but stressed no final decisions have been made. Mr Donohoe’s spokeswoman last night declined to comment but said the final decision will be announced next week “in the context of the capital plan”.

The Government’s capital plan was due to be announced on Wednesday but has been postponed until next week. The rail link to the airport is expected to be the centrepiece of the plan.

Mr Donohoe was presented with a list of six options by the NTA last year, including two different Dart links, a Luas from the city centre to Swords, a rapid bus system, the revised metro plan and a combination of a Dart and a Luas line.

While the Luas to Swords and Dublin Airport was the favoured option earlier in the year, sources said the revised metro plan is now more likely.

Mr Donohoe’s spokeswoman confirmed the chosen project will be one of the six options presented to him by the NTA. The NTA estimated the original Metro North would cost about €2.5 billion, with the so-called “optimised Metro North” coming in €452 million cheaper. Some sources suggested the cost of the revised metro could be as low as €1.8 billion.

Cost considerations

The new metro would follow a similar route to that proposed in the original plan, running from St Stephen’s Green to Swords via Drumcondra, Ballymun and the airport.

The original plan, which was granted planning approval in 2010 , was deferred on cost grounds by the Government on taking office in 2011.

The vehicles used would be similar to Luas trams, only longer, allowing for them to carry more passengers.

The proposed stations would therefore be smaller than originally envisaged, which the NTA report last year said would save €79 million. The rolling stock of vehicles could also be reduced by one-third, saving €46 million. Fewer stations are envisaged, saving €131 million. For example, the plan put forward by the NTA last year cut stations at O’Connell Bridge and Parnell Square in favour of one at Upper O’Connell Street.

Another difference is running the track overground for greater distances, saving €196 million.

The Cabinet on Tuesday decided to defer plans for a Dart underground system, linking the northern line near Connolly station with Heuston station and Inchicore on the south side. The Government has decided the proposed €3 billion tunnel under the River Liffey and the city centre, which formed a key element of the Dart underground plan, should be redesigned.

It gave the go-ahead for other elements of a blueprint to expand the Dart service including extending the existing line from Malahide to Balbriggan and electrifying other rail lines. Mr Donohoe said the extension to Balbriggan will be completed by 2022.