Would it be possible to mitigate the risk by ensuring that there is a backup diesel locomotive on hand?
The cancellation of scheduled services to allow for specials is ludicrous and counter-productive. For people from Longford and points further on the Sligo line, the fact that there is an hourly service down in the afternoon makes the train very attractive for holiday-time outings to the city since you don't really have to plan your return too seriously. With the 1600 gone for the summer, this makes the service dramatically less flexible.
A friend missed the 1505 by 5 minutes a few weeks ago and was dismayed to discover there was no 1600. She eventually got to Edgeworthstown (70 miles) at 1915 after the 1705 was delayed by more than half an hour. Well, delayed by 15 minutes since it is always 10 to 15 minutes late to Edgeworthstown. I could just about cycle the journey in that time.