New tunnel to bring train passengers into city - but don't get off at Heuston
Passengers travelling through the new Phoenix Park tunnel will have no option of exiting at Heuston Station - because of a lack of connectivity between platforms.
Up to four services per day will use the tunnel from the autumn 2016, as part of an investment of just under €14m.
The development will allow commuters travelling from Kildare to loop around the North Inner City and depart at Connolly Station or Grand Canal Dock for the first time. "This is a service that will be moving through this station, and will be moving through Heuston and then beyond," said Transport Minister Paschal Donohoe.
"The point of this work here is to provide additional services for people coming through Kildare. They'll move through this station and then onto the city centre stations," he said.
"The benefit of this is to an additional one million people, who are travelling in cars coming from Kildare and beyond, will be able to avail of an Irish Rail service that will take them into the city centre."
But Mr Donohoe admitted that such services will not initially stop at Heuston.
This is because the relevant platform - platform 10 - is too far from the central station.
However, the Fine Gael TD said this may change over time.
Mr Donohoe said that the new development will provide an incentive for passengers to take the train and leave their cars at home.
And he insisted that the Phoenix Park tunnel is not being seen as a replacement for the proposed Dart underground.
The new route will connect Kildare, Sallins, Hazelhatch and Cherry Orchard to Connolly Station, Tara Street, Pearse Street and Grand Canal Dock in Dublin 4.