Its primary purpose was to bring quarried slate down to the main line for onward transport.
It opened in July 1884, and a local passenger service was run as well as trains for the mineral traffic.
The slate was conveyed to Port Penrhyn, immediately east of Bangor for onward transport to market.
The line was duly built by the LNWR and opened for passenger traffic on 1 July 1884,[1] and for goods trains on 1 September 1885.
Occasional excursions ran after that date, as the area had a certain beauty, but the line closed completely on 7 October 1963.