That's according to the National Transport Authority, which says it's been an ongoing issue for over 18 months.
Tim Gaston from the NTA said the gangs were coming to Ireland specifically for the purpose of increasing their social media profiles.
Mr. Gaston says Irish Rail and its security have worked very closely with Gardai, and have arrested several of the graffiti artists.
Wicklow Graduates Among Those On ESB’s Award-Winning Programme
Millions Allocated To Regenerate Town Life in Co. Wicklow
Radio Backing Irish Artists Through Irish Music Month
Significant Rail Disruption For Wicklow Passengers This Weekend
Simon Harris Commits to Four Years of Income Tax Relief