Representatives of SIPTU, the NBRU and Irish Rail are to attuned Labour Court talks on Thursday.
It comes just a day after a strike at the company, with more actions planned on Tuesday November 14th, Thursday November 23rd and Friday December 8th.
The November 14th strike date will clash with the Ireland v Denmark World Cup play-off at Lansdowne Road.
Tens of thousands of commuters are facing disruption.
Management say they offered a 1.75% pay rise, based on new productivity measures.
However, unions rejected the deal - with Irish Rail workers saying they still have not been offered a 'no-strings' attached deal.
Workers are calling for a pay increase of 3.75% a year for the next three years - with unions saying staff have not been awarded a pay rise since 2008.
SIPTU transport division organiser, Greg Ennis, said: "SIPTU representatives have been invited by the Labour Court to attend a full hearing tomorrow morning with regard to the ongoing Irish Rail dispute.
"We have confirmed that SIPTU representatives will attend the hearing with a view to achieving an acceptable resolution of the pay dispute".
NBRU General-Secretary Dermot O'Leary said while the talks are "a potential step forward", he added: "It should be borne in mind that the intransigence displayed by Irish Rail management, led it should be said the CEO, together with tacit support from the Department of Transport, will make an overall resolution to this dispute more difficult than it might otherwise have been".
Iarnród Éireann says it welcomes the invitation and has accepted it.
The company says it has been "consistent in its position that the industrial relations machinery of the State provides the only forum where the current issues can be addressed and resolved.
"While at this time Iarnród Éireann has not been advised of a withdrawal by trade unions of the further dates of industrial action (14th and 23rd November, 8th December), the company hopes that the issues can be resolved in a manner that ensures customers suffer no further disruption to services".