Rail services between Athlone and Tullamore have been suspended until midday on Monday due to essential engineering work.
Iarnród Éireann said all train services on the Galway-Dublin and Westport-Dublin routes will involve bus transfers between Athlone and Tullamore in both directions until Monday.
The work, which involves the installation of two underpasses on the line between Athlone and Tullamore to eliminate three level crossings, are part of a national strategy to reduce the risk at level crossings.
Iarnród Éireann expects to carry up to 250,000 passengers over the October Bank Holiday Weekend.
A modified timetable giving full details of services on this weekend are available from all Iarnród Éireann stations, and details are available at the Iarnród Éireann Information line on 1850 366222, or online at www.irishrail.ie