This incline was built by the Conglog Slate and Slab Company after the grant of a lease of November 1874 by Cwmorthin, allowing Conglog to build a tramway through their quarries to join the existing Cwmorthin tramway at the Mill level. The lease was conditional on the head of the incline being at a level which allowed a new tramway from Cwmorthin's Lake Mill to join it. By 1900 the incline was owned by the Cwmorthin company. The double-track balance incline was 90 metres long, and crossed the stream by a wooden bridge at the lower end. The drum was 2.7 metres long and 1.1 metre diameter; it lay for many years by the side of the drumhouse, of which part of the lower walls survive.
W J Crompton, RCAHMW, 17 December 2008.