A fault on an overhead power cable in Co Wicklow has caused disruption to the Rosslare to Dublin train and some DART services.
All Dart services from Dalkey to Greystones are suspended as a result.
According to Iarnród Éireann, Dublin Bus will accept rail tickets from passengers travelling to or from affected stations. Passengers on the Rosslare to Dublin train will transported by bus.
Iarnród Éireann said services are expected to return to normal by around 3pm.