Update 5.40pm: Disruption to DARTs between Dalkey and Greystones is expected to continue for the rest of the weekend.
The line is closed after a fire caused by a technical issue, which damaged signalling equipment in the relay room in Bray.
Iarnrod Eireann spokesperson Barry Kenny says there will be no services tomorrow either.
"Certainly, Saturday and Sunday there will be no services between Dalkey and Greystones," said Mr Barry.
"Dublin Bus will be accepting rail tickets for customers affected while the Dublin-Rosslare services will have transfers between Connolly and Greystones.
"We will be doing all we can to ensure we have some services for Monday morning peak."
These arrangements will continue throughout Sat 19th & Sun 20th May.
DARTs are operating between Howth/Malahide and Dalkey.
Service arrangements for Monday morning will be confirmed as soon as possible.
Earlier: Dalkey to Greystones Dart line shut following fire
The Dalkey to Greystones line on the southside of Dublin remains shut this afternoon after a fire.
An investigation is underway into the cause of the blaze, which broke out in the relay room in Bray and damaged signalling equipment.
Iarnrod Eireann's Barry Kenny says they do not think it was caused by criminal damage.
He said: "We are investigating the cause of the fire. We do believe it was a technical issue rather than anything vandalism related or criminal damage.
"Within the relay room there is significant damage so we have to clean out that area and repair it because it is crucial equipment and the damage is significant."
Update 10.58am: Fire which has caused disruption to Dart service being investigated
A fire which has caused disruption to some Dart services on the southside of Dublin is being investigated.
The Dalkey to Greystones line is shut after it broke out in the relay room in Bray.
❗️Fire damage to signalling equipment at Bray: line closed Dalkey to Greystones
⚠️No DARTs between Dalkey & Greystones, Dublin Bus accepting tickets, transfer at Dun Laoghaire for buses
⚠️Bus transfers btwn Connolly & Greystones for Dublin to Rosslare trains— Iarnród Éireann (@IrishRail) May 19, 2018
The blaze damaged signalling equipment.
Iarnrod Eireann's Barry Kenny says a lot of damage has been caused.
He said: "The fire took place in a signalling relay room which houses a lot of the equipment that regulates the signalling of the network at 11.30 last night.
"The damage is quite significant and that's why unfortunately the line is closed this morning and will remain so at least for Saturday and Sunday."
Earlier: Dalkey to Greystones Dart closed as fire damages signalling equipment
The Dalkey to Greystones Dart is closed after a fire damaged signalling equipment.
The fire happened in the relay room in Bray.
It's not believed to have been a result of vandalism or criminal damage.
Disruption to the DART service is expected to continue at least across the weekend until further notice.
- Digital Desk