Originally opened in 1877, the line was previously used for freight services and for transferring trains to maintenance depots, as well as for special events like matches and concerts.
The line is now open to commuters for the first time in more than 100 years with the addition of seven new morning trains, serving all stations from Newbridge/Hazelhatch to Grand Canal Dock including Drumcondra, Connolly, Tara Street, and Pearse.
Eight new evening trains from Grand Canal Dock are now also running.
Iarnród Éireann says the service gives a direct public transport connection between stations in south-west Dublin and north Kildare, as well as to the central business district between Connolly and Grand Canal Dock.
The Phoenix Park Tunnel line will also connect customers travelling on longer distance commutes to and from Kildare and Portlaoise, according to Iarnród Éireann.
With €13.7m invested in upgrading the tunnel, Iarnród Éireann and the National Transport Authority (NTA) expect to expand the line’s services in the future to include off-peak and weekend times.
Regular commuter services did not operate through the tunnel in recent years due to constraints at Connolly Station. These constraints have now been addressed by recent resignalling works, Iarnród Éireann says.
Transport Minister Shane Ross said the Phoenix Park tunnel line is a vital part of rail infrastructure.
“I know that it will prove to be of immense benefit to the travelling public, as will other transport projects such as the Luas Cross City line opening in 2017. I am very proud to be one of the first commuters to travel this line and I heartily encourage others to do so.”
Chief executive of the NTA Anne Graham said the organisation is delighted services have commenced. “Together with city centre re-signalling, the new services ensure we will exploit the full potential of existing rail infrastructure at minimal cost, offering more rail travel options for public transport customers.”
Iarnród Éireann chief executive David Franks welcomed new and existing customers to the services. “By offering direct connections from stations between Newbridge and Parkwest to the south city business district, previously unavailable by public transport, we will encourage more commuters to switch from our congested roads to a fast and efficient rail transport alternative.”