Six more strikes have been threatened by Luas workers.
Union chiefs at Siptu said the operations company Transdev were being given lengthy notice in the hope of creating a window for talks.
Five 24-hour strikes are planned on the tram lines for Thursday April 28, Wednesday May 4, Friday May 13, a week later on May 20 and a week after that on May 27.
A separate four-hour stoppage is also planned for Thursday May 26.
Owen Reidy, Siptu negotiator, said: "The reason why we did this today and gave such lengthy notice is to create the space and opportunity for talks in the hope that the strikes won't have to happen."
But the union representative said there had been no contact from industrial relations mediators at the Workplace Relations Commission since talks broke down before Easter.
Mr Reidy described relations between workers and management as fraught.
"There's a window now. There's a good two-and-a-half weeks before the next strike to try and fix this and resolve it. It would be our hope that it would," Mr Reidy said.
There have been eight strikes to date and two others have already been notified to Transdev for April 23 and 24.
The increasingly bitter row centred on original pay claims ranging from less than 10% for some workers to 52% for those on lower scales.
Transdev claimed the deal put on the table would have given "substantial increases", including a driver on €42,247 earning €50,000 by January 2019, alongside a bonus of €3,250.
The company's offer that would have given existing staff increases of up to 18% over 33 months was pulled after it was rejected by workers.