Part of the Rhiwbach Tramway that linked with the Maenofferen Quarry railway system. The Rhiwbach tramway was built in 1863 to provide an alternative outlet for slates from Rhiwbach, Cwt-y-Bugail and Blaen-y-Cwm quarries. The tramway ran to the former main line of Ffestiniog Railway Diffwys Station in Blaenau Ffestiniog. There are three counter-balance inclines on the route of the Tramway, numbered from 1 (lower) to 3 (higher). Incline 3 ran from the tramway and transported slates from Rhiwbach, Cwt-y-Bugail and Blaen-y-Cwm quarries under gravity down to the level of the Upper Maenofferen Slate Quarry Mills. The incline is some 250m long and 3.5m wide and is a stone built structure. Its associated winding house (NPRN 65652) lies at the upper north end.
