Rail workers in the south west are to stage a 24-hour strike on Monday next in protest at changes to work practices at Iarnród Eireann.
The move by line inspection and maintenance staff at the company is likely to cause major disruption to train services in Cork, Mallow, Tralee and Limerick.
Siptu, which represents the workers, served Iarnród Eireann with notice of industrial action which it said would take effect from midnight on Sunday until midnight Monday in the south west region.
The union said: "Rail workers are being forced to take industrial action because management is continuing to forge ahead with plans which undermine existing working conditions without agreement".
SIPTU branch organiser Willie Noone said: "Management is progressively introducing a five-day week spread over seven days for certain categories of workers and utilising contract workers to carry out essential work which should be done by our members".
"As no resolution could be found, after exhaustive negotiations our members had no option but to serve notice of industrial action on September 7th", he said.
Mr Noone said the staff regretted any inconvenience their action might cause the travelling public and remain available for talks over the week-end in an effort to resolve the issue in dispute.