Difficult choice of locations, though:
Westport: most operationally interesting with a junction to the Quay Line plus the "main" route over Altamont Street bridge
Newport: fairly cramped site, plus the challenge of the Seven Arches viaduct and two small connecting bridges either side, and St. Patrick's above the station.
Mulrany: high up on the hillside, with the possible need to replicate the Great Southern Hotel on the adjacent site below
Achill Sound: needs space for the sea around it, I'd have thought....