The Nenagh branch, and Junction - Waterford, should have a five year plan tested with a train every hour and a half, widely advertised and at discounted fares, giving connections to get people to limerick, Waterford and Dublin and back at reasonable times, especially for students and commuters. After give years, if it hasn't worked, then shut them.
Ennis to Athenry will never come close to being economically viable, but a railway is a social service too. If enough people use it, a case can be made for funding it. If they don't, it can't, and it has to close, or at least be mothballed. And if mothballed, adjacent farmers told that if they destroy or move the boundaries, or build over it, their structures will be removed without notice, and they'll be billed for the demolition work!
In order to determine REAL demand, Ironroad Eireann must first provide a good service, at realistic speeds, for a period of several years at least.