Normal weekday service resumes on the unaffected routes.
Around 20 train services have been cancelled because of Covid-19.
Staff absences has caused disruption to services on Grand Canal Dock and Heuston Commuter routes between today and Friday.
No midlands services have been affected, although there is some disruption in Carlow and Newbridge.
Irish Rail spokesperson Barry Kenny is asking people to check the updated timetables:
Normal weekday service resumes Tues 4th January.— Iarnród Éireann #StaySafe (@IrishRail) January 3, 2022
However, due to current COVID-19 & close contact absence levels, some Phoenix Park Tunnel & Heuston Commuter services will be cancelled Tues 4th to Fri 7th January
Please check https://t.co/r50m2431AZ for full details of services pic.twitter.com/Q8E8sb61do