A decision will be made by June on a rail link. A number options were conaidered and being looked at. The following are front runners.
The DART spur between Howth-Airport/Swords with a 15 minute frequency to the city and routes such as Cork and Belfast running while the new cross city tram (opening) 2017 (Green Line) would be extended from Broombrdge and operate under ground to the airport to allow high speed.
If you ask me both will go ahead as the whole city and commuter belts would have acces and the DART will only cost 300 million. Basically Belfast-Rosslare would be connected.