I was on the same train this morning, although whether it was the Cork train or the Portlaoise train was debatable.
Some people thought it was the Cork train that had been delayed and arrived at 8.11 in Kildare (the same time as the Portlaoise train). However, the train stopped in both Hazelhatch & Sallins, which would suggest it was the Portlaoise train that was on time when it reached Kildare and the Cork train had not arrived.
Either ways, the train was jammed. I "just" managed to get a seat in the first class carriage after walking the entire length of the train. By the time it stopped at Newbridge, there were people standing in the aisles of the carriages (including the first class carriage!)
