It would seem that you can't book anything on-line to / from a Dart station or the Maynooth line to other stations unless it happens to be an actual stop for the intercity / suburban train. Oddly, you can on Cork line, eg Hazlehatch to Cork, and some of these journeys require 2 changes.
They probably assume you will use a leap card for the suburban part of the journey.
From my local southside Dart station ticket machine, I can buy a ticket to any northside or southside station between Rosslare and Dundalk, but I don't know if the reverse is true.
Last edited by Eddie : 14-08-2021 at 11:29.