RUSH-HOUR commuter services were delayed by up to 30 minutes this morning after a truck hit a bridge in Clontarf.
It is understood that the driver failed to stop after the incident, which happened just after 8am.
Gardai are investigating.
A bridge inspection took place immediately afterwards, and the structure was declared safe.
Cross-city and inter-city train services resumed within the hour.
However, Irish Rail said there were ongoing delays of between 20 and 30 minutes across the network as they tried to clear the backlog of commuters.
The Belfast to Dublin Enterprise service suffered minor delays, with the train due in to Connolly at 9.04am arriving 14 minutes late.
Irish Rail issued a tweet in the aftermath of the bridge strike to the driver of the vehicle.
It read: "To the trucker who hit bridge, failed to report it and left scene: we have your reg and company you drive for. Talk soon, lots to discuss."
They later wrote: "It's a basic rule of the road for hauliers. They must know their load heights and plan route accordingly."
Meanwhile, there were two separate traffic accidents around Firhouse early this morning.
One crash was cleared on the M50 northbound after J12 Firhouse, but delays continued through to the Red Cow.
Another crash, southbound after J12 Firhouse in the hard shoulder, caused slight delays in the area.