A damning indictment of Irish Rail's Intercity service.

[Thomas Ralph]

Originally Posted by Colm Donoghue

This procedure occurs only in Heuston. In Connolly, Drogheda, Rush and Lusk, Donabate, Westport, Balbriggan, Arklow, Kilcoole, Dun Laoighaire you buy your ticket and go onto the platform to board or wait for your train.

You'll find that there are several other stations which have ticket checks before people enter the platform and people generally aren't let onto an empty platform, for example Limerick (platforms 1 and 2), Waterford, Galway, and Cork. It also happens some of the time at Cobh. Seems to be exclusive to terminal stations.