One rail link from Heuston to Belfast line via Phoenix Park rail tunnel is essential to link up whole rail network. This line from Heuston via the existing Park Rail tunnel via Brombridge to Blanchardstown (half way to Airport) then alongside M50 to Airport then to Swords and joins Belfast line at Donabate. This links up the whole rail network. With standard rail gauge trains can go direct to all areas. The Dart line from Malahide can go direct to the Airport. This gives a Direct Belfast to Cork link. Direct link for Maynooth to Airport & Wexford via Adamstown. All areas of Ireland have direct access to and from the Airport. Adamstown Station has direct access to all areas in O3. See proposal on O3 leaflet where the city rail network slots in adequately for all areas. Standard gauge allows Dundalk rail to more than treble train use. This can’t happen if Metro North is built because of difference in the rail gauge. Country users can access trains at outskirt stations for convenience etc. Phoenix Park tunnel is more important than ever for a rail link to Belfast via Dublin Airport. Standard rail gauge is more important as it allows country trains to more than double, links Airport, links Malahide Dart line direct to the Airport & links up full rail network in Ireland.