The Croesor Tramway was built c1863 by Hugh Beaver Roberts to connect Croesor Slate Quarry, 480 metres (1620ft) above sea level, with quays at the harbour of Portmadoc. It was built without Parliamentary approval, about seven miles long and to a gauge of 600mm (1ft 111/2in). Slate waggons were lowered by gravity down two inclines to the floor of the Croesor valley, where they ran on a level and almost straight course to the summit of two further gravity inclines, the Upper and Lower Parc inclines, which lowered them to the low-lying reclaimed levels of the former Glaslyn estuary. Horses provided the motive power on the level sections. The given location marks a point in the flat-floored Cwm Croesor.

The lower level section of the Tramway was converted to a public railway, the Croesor and Portmadoc Railway, in 1865, but the inclines and upper section remained private. In1866 a link to Rhosydd Quarry by a further incline was made (NPRN 400884). In 1923 most of the lower section became part of the Welsh Highland Railway, which closed in June 1937 but was reconstructed and reopened in 2010.
W J Crompton, RCAHMW, 15 December 2011.