Gardai in Howth received a call at around 6pm advising them of a public order incident in progress.
It is understood a large group, mainly of young people, were causing disruption at Bayside Dart station. It is believed up to 50 youths began a fight.
A Garda spokesperson told Independent.ie that the crowd was dispersed, and that no arrests were made. There were knock on delays due to the incident.
Irish Rail tweeted: "17:45hrs Howth Bray currently running 30mins late due to awaiting the arrival of Gardaí at Bayside. It will terminate at Connolly"
Just three weeks ago, the station was badly damaged in a vandalism incident.
In that incident. witnesses said the gang of around six teens went ‘absolutely berserk’ and just smashed the windows and doors for no reason at all.
The gang were then said to have ran onwards to Baldoyle where they destroyed a shop and attacked the discount supermarket store.