Fantastic stuff, and well worth opening this discussion again for.
As can be seen, the mileage of PROPOSED railways ll over Ireland at various times probably equalled the mileage actually built!
While researching Clifden, Achill, Loughrea and one or two other projects that are ongoing, I've come across numerous possible routes to all three. Loughrea was served from Attymon Junction, but at one time there was a proposal to make it a terminus of a line from somewhere around Claremorris or Ballinrobe. Another early proposal had it on a more southerly MGWR main oine, while another again would have seen it as the terminus of a WLWR branch from Gort, or a GSWR line from Portumna!
Both Achill and Clifden had 3ft gauge proposals which came to nothing, as well as 5'3". In the case of the former, Achill was not even supposed to have been the terminus - Mulrany was; and any possible extension to that was to go north to Bangor Erris and Belmullet, not west. In the case of Clifden, one proposal - among the most nonsensical ever seriuously put forward anywhere - would have resulted in a HORSE tramway around Connemara's coastal villages, and the journey from Galway to Clifden would have taken 4-5 hours, even if they had later brought in steam trains.
Then, as now, the hearts of some rule their heads. Same as the chorus we hear today from some insisting that all closed lines should reopen. Some should never have been built in the first place.
While I have no plans at present to write a book on the "might have beens", I may refer to this issue in coming scribblings.