The man in his 50s who was arrested in relation to a firearm incident at Connolly Station has been released without charge.
Gardaí said a file will be prepared for the Office of the Director of Public Prosecutions.
The man was arrested after a suspected firearm was reportedly seen on a train arriving in Dublin on Wednesday evening.
Gardaí said that shortly after 6:20pm it received a report of a male passenger with a suspected firearm on a commuter rail service arriving into Connolly Station.
The person is not alleged to have made any threat towards any passenger on board.
A large scale response involving several Armed Response Units was deployed to the Dublin station.
Connolly Station was evacuated “to ensure full public safety”, gardaí said, and a security sweep of both the station and the train on which the person was a passenger was conducted.
The station reopened at around 7.25pm as there were “no ongoing public safety issues”, gardaí said.
Investigations are ongoing.
