Iarnród Éireann has launched a website that aims to encourage DART customers to take small changes to increase capacity on the network.
Speaking on RTÉ's News at One, Barry Kenny of Iarnród Éireann said that one in six weekday journeys on the DART are made between 8am and 9am.
He added that with schools and universities also back, mornings between now and the middle of December are the busiest commuting time of the year.
Mr Kenny said the new peaktime.ie website gives commuters information about how busy each train is. He said that this will allow commuters who have flexibility in their schedules to check which trains are quieter and to take those.
While he said it is reasonable to assume most people travelling in the peak time are doing so because of fixed work schedules, Iarnród Éireann have been engaging with employers and he said there is an increase in flexible working options out there.
He said that in some instances a change of one train, which is a ten-minute interval change on a DART commute, can help increase capacity.
"There will be people who realise with quite small changes there is greater comfort out there and hopefully encourage more people to travel by rail," he said.
Mr Kenny said the idea of the campaign was to try maximise the volume that can be carried on DART services within the capacity they have at present.
He added that the company is also investing in new trains, but added that these cannot be delivered at once and it would be years before they arrive.
He said when additional services are provided the aim is not to provide more space for existing customers but to encourage more people off the road network and onto public transport.