The man was arrested after a suspected firearm was reportedly seen on a train arriving in Dublin on Wednesday evening.

Armed gardaí entered the station in Dublin city centre during the incident.

The works will see 4.2km of track fully replaced from Connolly Station through to Pearse Station.

The Irish government has invested 25 million euro to facilitate the increased number of services on the route.

The first Enterprise train left the station at 8.05am on a journey to Dublin Connolly Station.

In August, Irish Rail warned customers that departure times were proposed to change on many Dart, Northern Commuter, and Maynooth Commuter services.