A Bay platform is a terminal platform at a railway station that is located on a through railway line. Historically, such platforms existed at stations where a branch line starts/ends. There was a bay platform at Mallow, Co. Cork, called the “Waterford Bay” as it was used by trains travelling to/from Waterford. A similar platform existed at Portlaoise for trains to Kilkenny running via Abbeyleix.
Nowadays, bay platforms can be found at Ballybrophy for trains to Limerick, Manulla Junction for Ballina trains and Clonsilla for M3 Parkway trains.
A modern day equivalent is the ‘turnback siding’ where a bay platform is provided at a station to allow a commuter service to travel to that station and clear the running lines before ‘turning back’ to its original location. Turnback sidings exist on the Kildare Route at Adamstown and Hazelhatch & Celbridge.