The “Dublin Area Rapid Transit” (DART) service started in 1984, over 30 years ago.
For the first 15 years it ran between Howth and Bray, and then a branch was added at Howth Junction and Donaghmede so that some darts could go to Malahide instead of Howth.
There is talk now of extending the Malahide Dart line all the way to Balbriggan by 2022.
I imagine the people living in Howth and Sutton were worried which the Malahide line was opened that half of the northbound Darts would be diverted to Malahide instead. But the strange thing is that, even after all of these years, this has never happened.
I regularly arrive in a Dart station to see that the next two Darts are going to Howth and the one after that will be going to Malahide.
All I can conclude is that there is a very powerful politician living in Howth.
Here is a picture from one of my favourite apps (“Next Train Ireland”) showing not 2 but 3 Howth Darts between 2 Malahide Darts: