It's a general Irish Rail thing. The 06:15 from Longford is a shade over 70 miles and again a shade over two hours. Even the 0545 from Sligo which doesn't stop between Maynooth and Drumcondra takes an hour and 50 minutes.
The bus is about the same for me but the level of comfort on the train tips the balance so long as I can avoid 29Ks. I generally arrive into work with an hour's work done already which I couldn't do on the bus.
Journey time isn't everything and it is hard to see how Irish Rail can feasibly compete on journey time given their present economic constraints. They can however compete on comfort if they avoid shooting themselves in the foot but cutting back on capacity.