DART services between Bray and Greystones are suspended this morning due to a landslide on the line.
Services were halted at 3.30 p.m. yesterday. Bus transfers were put in place on the Dublin-Rosslare route.
A spokesman for Iarnród Éireann said it hoped to put such transfers in place again this morning. But he said it would not be able to cope with the normal passenger demand and urged people to make alternative travel arrangements.
The company will not reopen the line until lunchtime at the earliest.