Update 6.45pm: Irish Rail is accusing its own staff of stopping it from introducing more frequent services.
Irish Rail's Barry Kenny says their resistance means the company could be unable to meet growing demand.
"We have record passenger numbers achieved in 2017 matching the previous high," said Mr Kenny.
"Clearly there is a need for us to respond to our customers needs and the needs of the economy by growing the service.
"So unfortunately, this ballot coupled with the last 20 months are restricting that ability."
Earlier: Train drivers have voted by an overwhelming majority to reject a Labour Court recommendation on pay and productivity measures.
The Irish Rail drivers, who are members of the SIPTU union, voted by 83% to 17% against the measures in a ballot counted today.
More than 93% of drivers from the NBRU union also rejected the 1.15% pay rise awarded by the Labour Court.
The 1.15% pay increase was on top of a 2.5% general yearly increase for the next three years for all Iarnród Éireann staff.
The pay hike would have allowed for driver training which would lead to more frequent services.
NBRU General Secretary Dermot O'Leary said management and unions had to examine why the proposal was rejected.
He also warned that there would be problems if the company "pressed the nuclear button" by unilaterally implementing changes.
- Digital desk