Iarnród Éireann has said DART services could be disrupted for the rest of the day due to a power issue with overhead lines at Grand Canal Dock.
Rail services between Pearse and Dún Laoghaire are suspended until further notice while staff work to repair a “significant issue to overhead line equipment”.
“Disruption is expected to continue for an extended period of time, including during this evening’s peak service,” a statement from Irish Rail said.
Iarnród Éireann’s Head of Corporate Communications Barry Kenny said the cause of the damage is unknown and staff are investigating.
DART services are continuing to operate between Howth/Malahide and Pearse, and between Dún Laoghaire and Bray/Greystones, but commuters are advised to expect delays.
The Rosslare intercity service has also been impacted by the disruption, with bus transfers in place from Connolly Station to Bray where there will be trains operating to Wexford and Rosslare Europort.
However, Iarnród Éireann said significant delays may result due to availability of buses and traffic conditions.
It added: “Northern commuters shall operate to/from Connolly/Pearse-Drogheda.
“Maynooth/Hazelhatch services will operate to/from Connolly/Pearse.
“Knock-on delays to all services in the city centre can be expected due to congestion on the line.”
Irish Rail has also apologised to commuters for the disruption, adding that Leap Cards can be used on all TFI transport in the affected area, subject to capacity.