Plans for a Dart tunnel under Dublin have been knocking around in some form for almost 50 years. Periodically they are picked up and played with by the government of the day, but ultimately Dart underground has always been discarded in favour of less costly options.
Its day appeared to have come in 2005, when the number of zeros at the end of a bill seemed of little importance. Dart “interconnector”, as it was then known, was part of an expansion programme to bring the Dart to Drogheda, Celbridge and Maynooth, with a price tag of more than €4 billion.
The tunnel element was to run in a semi-circle under the city with stations at Spencer Dock, Pearse Station, St Stephen's Green, Christ Church and Heuston. By the time Irish Rail applied to An Bord Pleanála for the line in 2010 its prospects appeared doubtful. In November 2011 the project was shelved.
The underground, while listed in the Transport Strategy for the Greater Dublin Area 2016-2035, was not in the 10-year National Development Plan published in 2018. Last year, the National Transport Authority (NTA) published plans for the Dart expansion priced at €2.6 billion, but again the underground project was not included and its prospects appeared ever more remote.
However, the NTA has recently begun planning for its development, with consultant engineers engaged to devise route options for the line. Questions might be raised about the need for this line, given the reopening of the Phoenix Park tunnel which takes commuters from the west of the city to Connolly. However, it has limited capacity and for most people Heuston is the last stop before they have to switch to the Luas or bus. This makes it more difficult to persuade people to leave their cars at home.
Digging a tunnel through the city centre would be expensive, but it offers a real prospect of alleviating traffic congestion from the west. It is worth considering as part of the major investment programme now planned for public transport.