The Dublin to Cork rail service is to get 67 new carriages providing an hourly service starting this winter.
Iarnród Éireann is to get a further 156 new carriages over the next three years which, it says, will transform the fleet from being the oldest in Europe to one of the most modern.
The Dublin to Limerick line is to also get an hourly service by 2008 while the Galway, Waterford and Sligo routes are due to be running at least every two hours.