Dart Plus West is the section which runs from Maynooth and the M3 Parkway into the city centre.
Planning permission for the Dart Plus West is live.
Irish Rail says two separate judicial review processes taken against the planning board's decision to grant it have been withdrawn.
The line includes remodelling Heuston Station, adding a new Station at Spencer Dock and a new entrance for Connolly Station.
Irish Rail expects the Dart Plus series of projects to double passenger capacity in the greater Dublin Area.
Dart Plus West is the section which runs from Maynooth and the M3 Parkway into the city centre.

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