They'll be carrying out some essential works on the tracks.
Irish Rail have warned customers travelling from Heuston Station this bank holiday weekend of planned diversions.
Friday May 3, Saturday May 4 and Sunday May 5 will see multiple diversions and a series of bus transfers to and from Heuston Station as essential track maintenance work is carried out.
Four services to and from Limerick to Heuston have also been cancelled on Saturday with one service from Heuston to Cork and one from Tralee to Heuston cancelled on the Sunday.
There will also be no DART services between Malahide and Howth Junction on Saturday or Sunday.
A statement from Irish Rail reads:
"In particular, customers travelling on Saturday 4th and Sunday 5th May should note that track renewal works between Hazelhatch and Newbridge, and between Clongriffin and Malahide will see bus transfers on all Intercity trains to/from Heuston, and no trains operating between Howth Junction and Malahide.
"Customers on all Heuston routes and connecting services are advised to check times before travel. We apologise to customers for the inconvenience caused by these essential works."
Bus replacements for the majority of services will operate from Heuston at an earlier time than the scheduled train departure.
A full list of diversions for the bank holiday and the rest of the month can be found on
Irish Rail's website.
