Iarnród Éireann has warned of service alterations due to engineering work this weekend.
In Dublin a line closure between Connolly and Howth/Malahide/Skerries, means DART services will only be operating between Connolly and Greystones today and tomorrow.
Northern Commuter and Enterprise services are also affected.
With regards to intercity services to and from Dublin Heuston today, bus transfers have been in place since 1pm due to line works between Hazelhatch and Sallins.
Full details of the changes are on the Irish Rail website.