Here are some pics of the railway tunnel under the Phoenix park. There is even a platform there visible at the Heuston end of the pic, Iarnrod Eireann should reopen that line and make good use of a piece of infrastructure thats already in place.Sorry if u can barely see the tunnel entrance, my camera is crap.On the 2nd pic just follow the railwayn line around and you’ll see the entrance between the apartment buildings.