Irish Rail website to-day (June 5th, 2019) has notice of a consultation process on possible extension of the WRC to (i) Athenty-Tuam and (ii) Tuam-Claremorris. It appears to be done in conjunction with the Department of Transport. No mention of the NTA. Strange why an operating company should have a role in this and not the National Transport Authority.
This bears out all the suspicions I have about the chaotic governance structures for public transport in Ireland.