A public consultation is to be held on the proposed €3bn MetroLink connecting Swords to Sandyford via Dublin Airport.
Once operational in 2027, it will be able to carry 30,000 passengers an hour in both directions.
Some 4,000 jobs will be created during its construction.
The proposed MetroLink route | Image: metrolink.ie
The emerging route - which has not be finalised - is to run between Swords and Sandyford, connecting key destinations including Dublin Airport and the city centre along a 26km route.
— Juliette Gash (@JulietteGash) March 22, 2018
A large proportion of it will be underground, including where it passes under the city centre area and the airport.
Under the plans, the Luas Green Line will be upgraded to metro standard.
MetroLink will have a total of 25 stations, including 15 new stations, and a journey time of approximately 50 minutes from Swords to Sandyford.
Under the National Development Plan, the previously proposed Metro North and Metro South are the one project - known as MetroLink.
Around 100 properties and at least two sports clubs will be affected by the project.