Transport Minister Paschal Donohoe has renewed his call for planned strikes at Irish Rail to be called off.
The work stoppages, which are due to begin on August 24, will coincide with the All-Ireland hurling and football finals in September.
Members of the National Bus and Rail Union and SIPTU are taking the action over pay cuts of up to 6%.
Paschal Donohoe said the cost-saving measures are necessary as Irish Rail is facing losses of €500,000 a week.
"These cuts are absolutely essential for the long-term viability of this company," he said. "That is why I'm being very clear the strike should not go ahead."