Computer glitch blamed for chaos on commuter trains
A software upgrade is thought to have caused a signalling fault that affected around 20,000 rail commuters.
Many people were left stranded and waiting for information on Tuesday morning after first hearing about the problem on the radio.
And although the matter has now been resolved, Irish Rail said it couldn't guarantee that it wouldn't happen again.
Company spokesperson Jane Cregan told the Herald that new software designed to increase the network's signalling efficiency did the exact opposite.
As a result, the computer at Central Traffic Control in Connolly "just went blank".
"Every signal controlled by this computer automatically went to red and stopped working," she said.
"There were a number of updates carried out in recent days on the system and we think one of them caused this fault to occur."
Ms Cregan added that during the crisis 15 to 20 operators were deployed around the country with manual access to signalling panels.
A team of IT experts managed to resolve the issue later that morning.
However, the fault caused knock-on delays for passengers coming in and out of Heuston Station throughout the afternoon.
Some InterCity services were running an hour-and-a-half late while there was reduced capacity on some services.
"I'm not aware of the ins and outs of how they got it back working again, but what's important is that it's fixed, and the updates have been completed," Ms Cregan added.
"We can't say that it will never happen again, but I have no reason to believe it will."
There was anger among some commuters that Irish Rail failed to provide bus transfers for affected passengers, some of whom said they were two hours late arriving at work on Tuesday morning.
Among those whose travel plans were thrown into chaos was Aisling Toms, who was with a group from Musgraves Wholesalers.
"We actually heard it on the radio before anyone in the station told us," she said.