It follows all trains nationwide being stopped earlier on Monday evening.
On Monday evening, Irish Rail announced that all lines would be stopped due to a major signal fault:
Due to a major signal fault, All DART and Commuter services are currently stopped. Update to follow
— Iarnród Éireann (@IrishRail) February 4, 2019
Soon after this, they followed up with another statement, saying that the signal fault had been rectified, but that it would have a major knock-on effect on all DART and commuter services around the country:
Update: Signal fault has been rectified, but expect knock on delays of up to 30mins to all DART & Commuter services and Sligo, Belfast & Rosslare services
— Iarnród Éireann (@IrishRail) February 4, 2019
All passengers should be prepared for delays nationwide, and keep an eye on the Irish Rail Twitter page for updates.