The general secretary of the National Bus and Rail Union (NBR), Dermot O’Leary has repeated a call for a dedicated transport police force.
He was responding to a report that Irish Rail has received 105 complaints of anti-social behaviour on the Dublin-Cork line since the beginning of last year.
According to documents released under the Freedom of Information Act to Newstalk, many of the complaints relate to drug activity on trains.
In one complaint, a passenger called on Irish Rail to address "junkies dealing drugs" all day outside Heuston Station.
Other complaints included two passengers going to and from the toilet taking drugs openly and a verbal attack by someone "out of their mind" on drink and drugs.
Another passenger claimed that on two Saturday evening trains, large gangs were carrying hurleys and knives while another commuter said a drunken passenger seemed to be taking ecstasy tablets on board.
Further complaints included a man “high on drugs shouting and roaring” at a woman - and another man making death threats.
But Irish Rail spokesperson Barry Kenny said these type of incidents are rare.
"We do have 4.5 million journeys during that timeline".
Dermot O’Leary told Newstalk Breakfast that he was very concerned about the figures.
He described last Friday’s crackdown on violence on public transport by Gardaí as “tokenism.”
On Friday up to 50 Gardaí boarded DART, LUAS and commuter rail services from 3pm for the remainder of the evening in an effort to deter crime.
Mr O’Leary added that text alerts and CCTV did not address the fundamental issue of anti social behaviour, he said which was “downright thuggery.”
“The bottom line is there needs to be transport police. It won’t fix the problem 100% but evidence has shown in other countries that it has led to a reduction in crime.
Mr O'Leary said members of his union feared that public transport, especially the Cork-Dublin train was effectively being used as a "drug corridor".
Gardaí have limited resources so a dedicated transport force was required, he said.