Lets be clear here its politicians
Metro north is just too big and takes too long like DART underground. Both are needed, the numbers stack up. But as long as we have parish pump politics its going nowhere, mayor for Dublin is the only way forward.
Navan, just isn't workable given the 450 million price tag and the lack of population centres on the route, the northern line in contrast as large towns dotted every few miles which generate large demand.
There is an urban myth about Croke Park, there is no station or provision for such, at the time of plans for the new children's hospital at the Mater there was talk of trying to locate a station eastward of Croke Park but came to nothing