A rail incident in Tralee occurred when a draw-bar on a train carriage gave way, an investigation has found.
The draw-bar on Sunday's 13.48 train to Dublin gave way between the fourth and fifth carriages of the nine-carriage train as it was pulling out of Casement station. About 100 passengers were on board.
Automatic brakes applied in both parts of the train, as part of the train's safety mechanism.
The draw-bar, which connects the coupling mechanism to the undercarriage, gave way, Iarnród Éireann spokesman Mr Barry Kenny said.
Stressing that investigations were continuing, Mr Kenny said this was "an isolated incident", and the company had not come across anything like it before in what are some of the more modern carriages on Irish railways.
Mark 3 carriages, made by British Rail, have been in use on Irish tracks since the 1980s and are still widely used in the UK and elsewhere. They have not caused problems for Iarnród Éireann.
"We have one of the best railway safety records in Europe and this is down to staff maintenance," Mr Kenny said. Carriages are checked every 48 hours, and given the equivalent of a car service. Detailed examinations are undertaken every six months.