A 24-HOUR strike over pay is to start on Monday by over 150 Translink staff.
Trade union General Municipal Boilers (GMB) confirmed on Thursday that the planned action was going ahead.
It is said the strike was in relation to “an ongoing dispute with the employer over pay and terms and conditions as well as a history of poor industrial relations”.
The workers are employed on the railway as conductors, station and platform staff.
GMB Regional Organiser Michael Mulholland said: “Our members in Translink on Northern Ireland Railways have voted to take part in action, up to and including strike action.
“All other groups have accepted a three-year deal, which has been achieved through the agreement of efficiencies such as changes to company sick pay and increased flexibility.
“GMB members, who are mainly from the Conductor and Station staff grades, believe that they are being asked to give away too much to fund increases for other groups who have not.”
Translink said it is working hard to resolve the situation with the trade union.
A spokesperson said: “Rail services will be affected by this strike action and we will keep our passengers informed as more information becomes available.
“Bus services will not be impacted.”