services between Sligo and Dublin will be hit by today’s strike.
Workers are seeking pay increases and a series of five one day strikes are planned, including Tuesday next.
Iarnrod Eireann estimates that €900,000 could be lost nationwide in revenue today.
Both unions, SIPTU and the National Rail and Bus Workers Union, support today’s stoppage.
Staff have also been warned that their individual losses could be over €1,200 if the series of one day strikes proceed.
Unions want an annual pay increase of about 3.75 per cent, unions say.
This figure is similar to the increase secured by workers at both Dublin Bus and Luas after strikes last year.
Iarnrod Eireann offered a 1.75 per cent increase for one year, in return for performance management and absenteeism management.
Also sought from workers are revisions to redeployment policy and payroll.
Meanwhile, the pickets today are likely to close all inter city and Dublin suburban train services.
The DART train service will not operate either, the company has advised passengers.
The company points to its 160 million euro in accumulated losses and says conceding the union claim would cost an extra 43 million over three years and push the company into insolvency.
Talks broke down a fortnight ago and there's no sign of any intervention to break the deadlock.
Irish Rail workers picketing a deserted Mac Diarmada Station this morning. Photo: SligoToday.ie
Four further 24 hour strikes are scheduled, including 14 November - the day of the Ireland/Denmark World Cup playoff.
And if the dispute isn't resolved with five stoppages, unions aren't ruling out an escalation in the run-up to Christmas.
Bus Éireann and Dublin Bus have confirmed that Irish Rail tickets are non-transfferable for their services.
Pickets in Sligo have so far today confined their activity to the rail station only leaving the bus station to operate as normal. This differs from the bus drivers strike earlier this year who also blocked entry to the adjoining rail station thereby causing maximum disruption to the travelling public..