DART and Commuter services have resumed but knock-on delays are expected after they had been suspended earlier this morning.
Iarnród Éireann said services were suspended between Raheny and Dublin Connolly following an incident on the line.
The rail operator added that it anticipates delays of up to 15 minutes as it "regulates services back to schedule".
In a statement, Iarnród Éireann said that bus transfers are in place for Belfast services from Drogheda.
Dublin Bus is accepting valid rail tickets in the capital and a shuttle service is in operation from Howth and Howth Junction.
