Minister for Transport, Martin Cullen, has announced the proposed routes and launched the consultation process for the second phase of the Metro which will serve west Dublin and connect with the Metro North to Dublin Airport.
The two proposed routes will branch off the Metro North line at the Metro Park station south of Dublin Airport. Minister Cullen described the new route as a much needed orbital route which would provide "a public transport alternative to the M50" which would significantly increase the connectivity of the current public transport system.
Route 1 would then follow the line of the M50 until it branches off to serve Blanchardstown town centre, Liffey Valley Shoppping Centre, Clondalkin Village and terminating in Tallaght village near the current end of the Luas Red Line.
The second proposed route would serve Blanchardstown Institute of Technology, Blachardstown town centre, skirt east of Lucan town centre before following the new Outer Ring Road to finish in Tallaght.
Both route options would interchange with Iarnrod Eireann's Kildare and Maynooth commuter lines and Railway Procurement Agency chief executive Frank Aiken stressed that the final route was likely to be a mixture of both proposals based on the consultation process.
It is hoped that the new line which will be between 24 and 28 kms long will be completed in 2014 with construction taking four to five years.
The RPA hopes that process would be completed "as early as possible in the New Year" and when completed an appication for a Railway Order would be submitted to the Minister for Transport within 12 months.
Minister Cullen declined to give an estimated cost of the new Metro as it will be built using a public private partnership agreement.