Over 25,000 homes and businesses have been reconnected after being hit by a power cut in Clonshaugh.
50 customers in Finglas are also affected by the outage this morning.
Irish Rail says services are back up and running after they were initially affected but there are delays.
Update: Services have now resumed on the northside. Expect delays due to earlier power outage
— Iarnród Éireann (@IrishRail) February 23, 2018
It's the second major outage in Dublin in a week after 4,500 customers were left without power on Monday.