Gardaí were called to an incident on a train in Tipperary on Friday evening.
A train from Cork to Dublin was stopped in Limerick Junction following a dispute on board.
Four Gardaí and a paramedic boarded the train, where there was a 50 minute hold up.
According to a passenger, a row began when another passenger had no ticket and refused to buy one or get off the train.
The individual was then said to have felt unwell following which an ambulance was called.