Commuters are to be given free bottles of water as the high temperatures continue.
Irish Rail say 50,000 bottles will be distributed to rail customers.
The company says hot weather protocols are in place for its fleet and infrastructure maintenance.
Fleet maintenance will focus on cooling systems on board, and on ensuring air-conditioning is operating well on equipped fleets.
This will be monitored remotely and in maintenance centres.
It has advised customers to stay hydrated when travelling during the hot weather spell.
The bottles are being distributed to customers free of charge at major stations over the coming days.
— Alex O' Keeffe (@Rocheeffe) June 27, 2018
On social media, the company is sharing a video with customers on tips for travel during the hot spell - including advice to always carry water.
Some track maintenance works are also being deferred, as unsettling the track bed can increase the risk of rail buckling in the heat.
However, engineers say rail heat levels have not approached levels to cause concern or to require speed restrictions.