Does Heuston have a secure bike parking facility?
It is such a pity that bikes can't be taken on off peak commuter services (I have sometimes seen people bring them on Sunday Maynooth services though).
I've seen people carry huge surfboards on trains but a bicycle is a no-no unless on an inter city train (and even only then with a good fight from ourselves
http://www.railusers.ie/passenger_info/bikes.php)
I wonder what the official reason for banning them on off peak commuter services is?