Some Dart train services in Dublin and Wicklow were cancelled this morning due to the theft of signal cable.
There was disruption to trains from Bray to Dalkey and there was a limited service Dalkey to Dún Laoghaire due to cable theft in Shankill.
Iarnród Éireann said Dublin Bus was accepting rail tickets for customers to and from stations south of Dún Laoghaire.
The rail company said services have now resumed but warned of delays. It apologised for inconvenience caused.