The length of Dublin's first underground rail line will be much shorter than originally planned.
Metrolink will only run from Swords to Charlemont, following concerns extending it to Sandyford would have forced part of the green Luas line to close for years during construction.
The National Transport Authority says it will upgrade the existing Luas line so that Metrolink can run along it, but it estimates that won't be needed for "perhaps twenty years or so".
The required tunnel boring works to allow the future connection to the existing Luas line will be completed as part of this current phase.
The location of a number of planned underground stations has also been moved, to avoid road closures.
O'Connell St, Stephen's Green and Ballymun stops have all been moved.
Planners say that will "reduce disruption and make it easier for other public transport services to continue to operate during construction".
The number of homes that will be lost to make room for Metrolink has also fallen from 105 to 85.
Na Fianna GAA club has been told it can keep its pitch, as it will no longer be used during construction.
Home Farm football club will be impacted for three years during construction, but will have its pitch fully restored.
It is expected that a Railway Order application will be made in 2020, with a decision from anticipated the following year.
Construction is likely to take six to seven years.
Anne Graham, CEO of the National Transport Authority said:
Metrolink will finally mean there is "a rail link to Dublin Airport, and with easy interchange with other modes including bus, Dart and commuter rail".
Transport Infrastructure Ireland CEO Michael Nolan said: “Last year we conducted a genuinely consultative process and we listened in an authentic public consultation exercise.
“For the last twelve months our engineers and designers have analysed every aspect of the alignment and developed a Preferred Route, which we believe will deliver the best service with the least impact on the city during construction.
“We look forward now to receiving feedback on this route so we can refine the design and proceed with making an application for a Railway Order next year.”
