Iarnród Éireann has said it was not feasible to run a shuttle train service between Lusk and Dublin city yesterday morning to facilitate commuters after a freight train derailed.
Up to 7,000 commuters suffered severe delays on the journey into the capital after the freight car derailed between Skerries and Lusk at about 11pm the previous night.
The company, which yesterday reopened the line to deal with the evening and weekend rush, said the track would now be closed until at least Monday.
Commuter trains and the Dublin to Belfast service will rely on bus connections between Dublin and Drogheda.
Responding to complaints that Iarnród Éireann could have set up a shuttle bus service around the immediate derailment scene, spokesman Barry Kenny said such a move would have had complex implications for the signalling system.
"We would have had to take trains into Lusk and reverse them out again on the same track which would have been a complex, unwieldy and time- consuming arrangement.
"If you bring a train into a signalling system and reverse out on the same track [ at Lusk] it would result in quite a lot of disruption to the Dart as well," said Mr Kenny.
The situation was made more difficult for commuters by the fact that the Bus Éireann fleet was fully deployed yesterday and spare buses were not available.
The company hired 14 private buses but even so commuters reported two-hour journey times between Donabate and Dublin city.
A Bus Éireann spokeswoman said 235 additional buses were promised to the company under Transport 21 and the majority of these were expected to come into service this year and next.
Iarnród Éireann has launched an investigation into how the derailment occurred.
The train was carrying six wagons of mineral ore from Tara Mines in Co Meath to the North Wall when it went off the tracks at Hacketstown, 3km south of Skerries.
It is hoped that normal services will resume by Monday morning. Iarnród Éireann apologised for the inconvenience caused.
Yesterday passengers travelling from Belfast to Dublin from early afternoon experienced two-hour delays en route, when trains travelling from the capital were given priority on the single line between Malahide and Skerries.
