Well in that case, that statistic is wrong on the Sligo line. The 1705 on that date did not operate beyond Mullingar. There was a 6 car ICR unit parked up on a siding when we went through on the 1805 about 90 minutes late.
I don't know how they resolved that issue on that day, but I guess that if they put all the passengers on the 1715 to Longford and ran it to Sligo, they could state that the service was "reliable". But there is a bit of a smell about the fact that according to the stats there hasn't been a single service that didn't operate so far this year.
In any case, this basically means that the reliability statistics are a complete waste of time.