Transport experts say it is becoming increasingly hard to justify rural rail routes that are losing money.
The warning follows yesterday's report by the National Transport Authority and Iarnród Éireann which shows almost €500,000 in funding is needed to run the network.
The service is losing around €100m each year.
Among the worst lines is the Limerick to Ballybrophy route which is costing the State €550, per passenger, per journey.
Dr. Sean Barrett Transport Economist at Trinity College it may not be sustainable: "I think the case for them is very weak, like Ballybrophy, like Limerick, Waterford.
"Railways need built up areas and ones that take an hour longer than a railway running parallel to it, don't really make much sense."