Iarnród Éireann has said commuters will face "significant" rail service disruption throughout the week between Greystones and Dalkey due to damaged signalling equipment.
The company has said services will be suspended between Greystones and Bray, while a reduced timetable will operate between Bray and Dalkey.
It comes as a result of significant fire damage to signalling equipment in Bray last Friday.
The company has said the fire occurred in a signalling relay room, and saw services suspended between Greystones and Dalkey throughout the weekend.
In a statement, the company said that limited bus transfers will be provided between Greystones and Bray for DART services.
It said that services will also be running at reduced capacity and speeds, adding that a service will operate every 30 minutes from Bray to Dalkey at morning peak, and from Dalkey to Bray at evening peak times, with reduced capacity.
Bus transfers between Greystones and Bray, Dún Laoghaire and Dublin Connolly will be provided for services between Rosslare Europort/Wexford and Dublin Connolly
After evening peak times, no services will run from Dalkey to Bray to allow repair works to take place.
Dublin Bus will be accepting rail tickets at all times for journeys to and from areas south of Dalkey.
