Irish Rail says Intercity trains to Dublin have almost sold out ahead of the papal mass in Phoenix Park later this month.
The transport company says trains must be booked in advance for Sunday 26th August, and is urging anyone who needs a ticket to book now.
Extra trains will operate to/from Dublin on all routes, while extra DART services will also be operating on the day.
It comes as preparations mount ahead of the World Meeting of Families.
A mass celebrated by Pope Francis is the centerpiece of the event, with 500,000 people expected to attend.
Margaret Gormley from the Office of Public Works said: "It's actually the largest event taking place in Europe this year. It's the equivalent of six Croke Parks on All-Ireland final day."
Measures are being put in place across areas such as transport, security and health.
More than 1,000 doctors and nurses will be on hand to help, while there's also a mortuary being set up among the other medical facilities.
There will be 1,600 stewards on the day and 3,000 people in the choir.
31,000 litres of milk and 25,000 sliced pans, meanwhile, will be used to look after the food and drink needs of people.
👇The view from the stage 👇
Here's what Pope Francis will see from the Phoenix Park stage when he's looking out at half a million people during the closing mass in just under 2 weeks #PopeInIreland pic.twitter.com/YQLAw30PoS
— Stephen Murphy (@Stephen_Murphy5) August 14, 2018
You can see a full list of current availability on Intercity trains, as of Tuesday lunchtime, below:
- Cork-Dublin: Almost sold out, last few seats available
- Tralee-Dublin: Sold out
- Limerick-Dublin: Almost sold out, last few seats available
- Waterford-Dublin: Sold out morning Waterford-Dublin, last few seats available evening Dublin-Waterford
- Sligo-Dublin: Still availability, book ASAP
- Galway-Dublin: One train sold out, limited availability on others, book ASAP
- Westport/Ballina-Dublin: One train sold out, limited availability on others, book ASAP
- Rosslare-Dublin: Still availability, book ASAP
- Westport/Ballina/Athlone to Claremorris (for Knock event): Still availability, book ASAP
