Subsidence on a section of rail between Dublin's Connolly Station and Clontarf Road has caused severe disruption to train services in the north-east.
Limited services are currently operating from Drogheda, Dundalk, Howth and Malahide, but they cannot get any further than Clontarf Road.
Fairview DART depot has also been cut off due to the subsidence, forcing the company to limit its services between Connolly Station and Greystones.
Iarnrod Eireann spokesman Barry Kenny said it will take some hours to repair the damaged line. He advised people travelling into Dublin city on northern routes to make alternative arrangements.