The Limerick to Ballybrophy via Nenagh railway route will be closed for two weeks from Saturday, January 29 to Sunday, February 13.
It will replace two miles of track, which along with last year’s work will reduce travel time.
During the track replacement, all railway services will be replaced by bus transfers.
Except for the 07:45 Nenagh to Limerick route, which departs at 7:30, serving Birdhill at 07:52 and Castleconnell at 08:05.
Affected customers have been contacted by Iarnród Eireann.