More than 15 years after it was first mooted, test drilling is finally under way for the proposed MetroLink across the Greater Dublin Area.
Transport Infrastructure Ireland (TII) has been conducting a series of ground investigation works over the past number of weeks, which involve drilling boreholes. To date it has completed almost 80 of these boreholes all around Dublin city and Fingal. There are about 40 more to complete.
Some of the most recent test drills took place at Hume Street and Albert College Park.
TII told the Irish Independent each borehole takes about a week to complete unless there are any technical challenges which might cause delays. However, a spokesperson said these are "very rare".
"Transport Infrastructure Ireland is conducting a variety of surveys along the proposed alignment to inform MetroLink's design, development and Environmental Impact Assessment Report (EIAR), which will form part of the application for a Railway Order," said a spokesperson.
"The surveys gather information on many issues including air quality, flora and fauna, ground conditions, current levels of background noise and archaeological features.
"As part of this process, we are conducting a series of ground investigation works which involve drilling boreholes," they added. The Metrolink will be a north-south railway which will run between Swords and Charlemont, linking Dublin Airport, Irish Rail, Dart, Dublin Bus and Luas services.
There will be 15 new stations, 3,000 additional park and ride spaces, and a journey time of 25 minutes from Swords to the city centre.
It is intended that construction work will start in 2021 and the first passengers will be on board in 2027.
The final cost of the project is still in dispute, with initial estimates of €3bn now believed to be at the lower end of what is likely.
The idea to build some form of underground rail line to connect the main stations in Dublin city centre has been considered for many years.