The Iarnród Éireann dispute over training and mentoring of drivers, and alleged breaches of procedures, is to be referred to the Labour Court.
It is understood that management and unions, who failed to reach a solution at the Workplace Relations Commission, have agreed to the referral for adjudication.
In the meantime, the unions will continue to carry out their strike ballot of drivers, the result of which will be revealed on 28 February.
Management has agreed to hold off on the proposed unilateral implementation of compulsory mentoring duties.
A statement on behalf of the National Bus and Rail Union and SIPTU said that despite their best efforts they had been unable to persuade management that the drivers' demand for a shorter working week should have "parity of esteem" with management's focus on the training/mentoring issue.
In a statement, Iarnród Éireann said it was unfortunate that the issues had not been resolved, but noted that both sides have agreed to refer the procedural issue of implementing mentoring to the Labour Court.
The company said it welcomed the WRC's assistance in seeking an early Labour Court hearing as it seeks to ensure driver training can resume.