Irish Rail has received several complaints of harassment and abuse towards passengers on the Dublin-Westport railway line.
A schoolgirl claims she was threatened with 'sexual punishments' by drunk men.
This is among 40 complaints of antisocial behaviour on the line in 2018.
Irish Rail says there were nearly 600-thousand journeys on this route last year and the limited number of complaints were 'regrettable.'
Fianna Fáil's transport spokesman, Sligo based Marc MacSharry, says this behaviour cannot be tolerated.