Rail services on the east coast and through Dublin's Connolly Station are due to come to a halt tomorrow as a new phase of industrial action by train drivers begins.
No talks took place over the weekend to head off the strike, which is being conducted by the ATGWU on behalf of more than 100 members of its recently amalgamated branch, the Irish Locomotive Drivers' Association.
The ICTU has appealed to the union to call off the strike pending a hearing of its case for union recognition on Thursday. However, the ATGWU's Irish secretary, Mr Mick O'Reilly, said union recognition was "a separate issue".
Had the company had not initiated disciplinary action recently against seven ATGWU members, he said, the strike would not be going ahead.
He added he was disappointed neither the Labour Relations Commission nor the Labour Court had intervened, and said the dispute could be resolved if the company agreed to talk.
However, a spokesman for Iarnrod Eireann said: "This is essentially an inter-union difficulty and the trade union movement needs to resolve it themselves. We are maintaining contact with the ICTU but would not be particularly hopefully it will be sorted out before Tuesday."
The ATGWU is in dispute with SIPTU and the NBRU, the two recognised train drivers' unions, over its right to represent ILDA workers. Under congress rules, no strike action should be taken while a dispute is being investigated.
Tomorrow's pickets will take place at Dundalk, Drogheda and two Dublin depots, Connolly and Fairview, causing disruption to east-coast services, the northern suburban line and the DART. Further strikes at these depots are planned for May 16th and 22nd.
Disruption to services in Munster and the west can be expected on Wednesday when the first of three days of picketing will take place at Cork, Mallow, Waterford, Inchicore, Limerick, Athlone and Portlaoise stations. The other two days of picketing for these stations are May 15th and 21st.
On Thursday, depots at Sligo, Ballina, Westport and Mullingar will be picketed, disrupting services in the midlands and northwest. Further picketing at these stations is due to take place on May 14th and 23rd.
Fine Gael's spokesman on enterprise and tourism, Mr Jim Higgins, urged the Minister for Public Enterprise, Ms O'Rourke, to ask the Labour Court and the LRC to intervene to head off the dispute. Mr Higgins said the tourism industry was "already on its knees" from the effects of the foot-and-mouth crisis. However, a spokesman for the Minister said it was not her function to intervene.