The idea of Farranfore as a rail-connected airport is a total joke and its almost a waste of time discussing it.
There is a train to Killarney or Tralee roughly every 2 hours. Do you really expect someone to walk 1.4km with luggage or take a taxi, for a mean expected wait time of one hour?
I don't expect Farranfore to handle any significant level of traffic making long-distance onward land connections: it's basically a Co Kerry airport and getting to anywhere in Kerry by train from Farranfore is likely to appeal to very few people.
Why is it that so much agitation for rail projects are for totally hopeless ones? The greater Dublin area is crying out for increased capacity yet we hear about people in the middle of nowhere complaining about things like the DART getting more money than the WRC.