Iarnród Éireann has cancelled Dart and rail services between Bray and Greystones for the rest of the day after a fire broke out on Bray Head.
Wicklow Fire Service said the fire started in front of a tent and “spread along steep ground east of the cliff walk at around 1am.”
The fire has now been brought under control – but the fire service said railway infrastructure has been damaged and is now being assessed by Iarnród Éireann.
It said the steep cliff face handed the fire a “protected route” down to the railway track to the track while crews fought the fire from above.
Iarnród Éireann said the line will remain closed for the rest of the day due to fire damage to signalling and telecoms cabling.
Spokesperson Barry Kenny said Dublin Bus will accept valid tickets until the line re-opens to passengers.
"Customers can use their rail tickets on Dublin Bus services and that would also impact on people travelling the Dublin to Rosslare line so we are going to have bus transfers between Bray and Greystones for people travelling on those particular trains," he said.