While rail is the obvious solution to the gridlock in Dublin and has been for years the car lobby is very powerful and well connected which is why solutions like rail to Navan and an airport line cannot attract political attention. When M50 was being built it would have been simple to run a luas type ssystem to the airport similar to other capitals. Opening up Phoenix park tunnel was like drawing teeth as CIE resisted with every possible argument. When Croke park was built it cleverly included a rail platform on the canal side but has yet to be used. The money is in motorways!