The exit tramway from Moelwyn slate mill descends by four spectacular balance inclines to a junction with the Ffestiniog Railway, now under the waters of Llyn Ystradau, the lower reservoir of the Festiniog pump-storage scheme. The grid reference pinpoints the position of the highest drumhouse; the others are at SH6726244279, SH7253244264 and SH6765844279. All are in ruins, the top one having lost one of its side walls, probably owing to the burying of cables which run from Llyn Stwlan to the power station along the line of the tramway.
W J Crompton, RCAHMW, 30 July 2009.