An abusive passenger delayed nine trains while he hurled insults at an inspector who confronted him for travelling without a ticket.
Kelvin Boye (30) - a data security analyst - held up mainline rail services for more than four hours as he falsely accused the inspector of asking for his ticket "because I am black".
After what was described as one of the worst "customer incidents" rail staff have had to deal with, Boye was taken off the train saying he had had his "moment of fame".
It was one of a series of incidents in which he either had no ticket or verbally abused staff.
Boye failed to appear at Dublin District Court, where Judge John O'Neill fined him €2,650 in his absence.
The judge said Boye was an "angry man" and staff had tried to reason with him.
Irish Rail inspector Daniel Kelly said he was on board the Maynooth train at Clonsilla at 9.36am last June 17 when he asked Boye for a ticket.
Boye had none, but told Insp Kelly he had a picture of the ticket-vending machine which he said was not working.
The photo was a selfie. Boye then started asking other passengers to look at his phone.
He became aggressive and angry and started "turning on people".
"He said, 'You called me a n***er. I know you don't like black people'," said Mr Kelly. "He called me a skinhead white guy. He was calling people drug addicts and saying customers looked like they were on drink."
The court heard there were 30 children on a school trip and Boye "just wouldn't get off" the train.
The train driver approached and Boye "wanted to have a go at him".
Everybody had to get off and it caused a 282-minute delay, with nine trains held up.
In another incident, on May 5, inspector Conor Daly said he was at Drumcondra Station at 6.30pm when Boye turned to him and said: "What are you looking at? You ain't gonna do s**t."
When told being abusive was an offence, Boye said: "F**k off, you are only stopping me because I am black."
Mr Daly said he called staff "dimwits" and remarked that "no wonder the English had taken us over".
Boye chopped down with a clenched fist on his wrist, saying: "Don't touch me."
Inspector Simon Kelly said that on May 25, Boye came through Drumcondra station with no ticket.
When confronted, he said: "Don't touch me, I will f***ing drop you."
When Insp Kelly called the gardai, Boye - of Parkgate, Verde-mont, Blanchardstown -pushed him over and ran off.