More talks are taking place this afternoon to try and avoid another rail strike.
Drivers are expected to walk off the job for three hours on Friday morning, after holding a similar stoppage last month.
The Workplace Relations Commission is holding exploratory talks with management and train drivers unions to see if a basis for renewed discussions can be found.
Meanwhile, Irish Rail is informing passengers of arrangements in the event that Friday's industrial action goes ahead.
If it proceeds, it will affect DART, commuter and intercity services between 6 and 9 a.m..
Iarnrod Eireann says trains will operate before and after the strike, although those after 9 a.m. may be hit with delays.
Passengers booked to travel on trains during the hours of industrial action can use their tickets on Thursday, later on Friday, or on Saturday - or receive a refund.
