Goods: you are wrong about Portugal. Like Ireland, and with roughly twice the population in a similar area, the Portuguese rail network is almost entirely focused on lines radiating from the capital, and also from Porto. Where services exist between provincial cities of comparable size to Limerick and Galway (50,000+) they are generally on part of an intercity route, e.g. between Coimbra and Aveiro on the Lisbon-Porto main line. South of the Tagus river, the main cities of Faro, Evora, and Beja are all linked to Lisbon by rail, but direct connections are between them are virtually non-existent. I could go on...
What we can learn from the Portuguese is (a) their impressive electrification of most main lines, (b) their big investment in suburban services around the two main cities and (c ) the Porto metro which is like a souped-up version of LUAS and crucially uses tunnels in the city centre (thus avoiding any College Green debacle).