Part of NPRN 40590. The double-track tramway incline connected the main working level, Level C (NPRN 408348), with the slate and slab mill at the foot of the steep valley side (NPRN 408357). It was a typical self-acting balance incline, the loaded waggons hauling up the lighter empties under the control of a brakesman at the top. The slope was 30 degrees for most of its 135 metres, except for the lower 15 metres which became progressively less steep. The upper part was embanked on walls of rough slate waste, and the lower part was in cutting. It probably dates from the 1873/74 period of development under the Conglog Slate and Slab Company Limited.
W J Crompton, RCAHMW, 22 October 2008.