This tramway connecting the slate quarry at Cwm Ebol (AditNow entry: https://www.aditnow.co.uk/mines/Cwm-Ebol-Slate-Mine/ ) with a small quay on the River Dovey. It was nearly 2 miles long.
The railway opened in 1865. Its gauge was originally 3', but later converted to 2'. By 1887, the line had been truncated to terminate at the road. The quarry closed in 1906, and the tramway materials were advertised for sale in 1907.
The lower trackbed of the tramway was re-used between 1918 and 1920 for another 2 ft-gauge tramway, serving timber felling operations at Cwm Dwr, 2 miles north of Pennal.
Wikipedia article: https://en.wikipedia.org/wiki/Cwm_Ebol_quarry_tramway