More trains are being put on at weekends to keep up with demand.
Irish Rail says it is continuing to monitor passenger numbers following criticism last weekend for overcrowding on a service from Galway to Dublin.
The extra trains will be on the Cork, Limerick, Tralee, Ennis and Galway lines from Heuston Station in Dublin.
Widespread criticism on social media followed a tweet from an Irish rail passenger on the 15:05 Galway to Dublin service that showed crowded compartment corridors.
50% of the seats are marked off so that people can socially distance - yet every carriage corridor looks like this. Impossible to get to the toilet without being on top of one & other. I don’t mean to sound negative - but this is not right @IrishRail @MichealMartinTD pic.twitter.com/hGhP43Fj5l— Holly Carpenter (@Holly0910) July 19, 2020
Jane Cregan from Irish Rail says they intend to have full services in place before the end of August:
Ms Cregan said: "We intend that we will have all services operating currently.
"We are operating the majority of services but not all services are operating at this time.
"We are working together with the National Transport Authority that we will have full services restored by the end of August."