Iarnród Éireann has announced significant rail works will take places at several locations across the country this weekend.
As a result a number of rural and intercity services will be impacted on Saturday and Sunday, the 24 and 25.
"Due to a series of track and signalling works taking place, the line between Portarlington and Limerick Junction is closed," Irish Rail said in a statement.
"All services between Dublin and Cork, Kerry and Limerick will see partial or full bus transfers, and to a revised schedule, with other services also affected."
Services between Cork and Dublin Heuston will operate between Cork and Limerick Junction only, in both directions, and to a limited timetable.
However, customers should note that for those travelling between Cork and Dublin Heuston, a bus transfer will be provided for the full journey.
Customers travelling from other stations, including will have bus transfers between Limerick Junction and Heuston. Please check times before travel.
Direct services between Limerick and Dublin Heuston will be replaced by bus transfer for the full journey in both directions, and operate to a limited timetable.
Journeys between Limerick and Dublin Heuston, involving a change at Limerick Junction, will have bus transfers between Limerick Junction and Heuston, and operate to a limited timetable, in both directions.
Services between Tralee and Dublin Heuston will involve bus transfers between Limerick Junction and Heuston, in both directions.
Services between Tralee and Mallow, and between Tralee and Cork, will operate as normal, with some minor time changes.
Commuter services between Portlaoise and Dublin Heuston will involve bus transfers between Portlaoise and Portarlington in both directions.
Limerick to Ballybrophy (via Nenagh) and Limerick Junction to Waterford services in both directions will operate to a revised timetable.
Meanwhile, due to signalling and coastal protection works, the line between Dun Laoghaire and Wicklow will be closed.
There will be no DART services between Dun Laoghaire and Greystones.
Dublin Bus and GoAhead will accept rail tickets to and from affected areas. DART services will operate between Howth/Malahide and Dun Laoghaire only.
The Dublin Connolly to Rosslare Europort Intercity services will involve bus transfers between Connolly and Wicklow, in both directions.
"Customers are advised to check times before travel, with full details at www.irishrail.ie and at the Iarnród Éireann app,” Irish Rail added.
“We apologise to customers for any inconvenience from these essential works.”