In 1861 the North Wales Chronicle referred to "Tenders invited to construct a tram-road 5 miles (8.0 km) long from Cwm Eigia [sic] slate quarry to River Conwy".

However, the tramway was initially only built as far as Cedryn, and in 1863 the Caernarvon & Denbigh Herald advertised for a contractor to extend west to Cwm Eigiau Quarry.

The line was built to standard gauge, and largely utilized the route of the former Cedryn/Eigiau Quarry tramway which ran along the lower slopes of Moel Eilio, though at Pwll Du, about half a mile above Coedty reservoir, a small northerly diversion was made in order to avoid a former small incline.

Today, whilst the line of the tramway can easily be followed, and makes a pleasant walk from Eigiau down to the head of the Dolgarrog inclines, there is no evidence of rails or sleepers of any kind.

Towards Llyn Eigiau the Tramway runs along a level path, though the gradients are greater through the woods immediately above Coedty.

It saw occasional use on the Cowlyd Tramway, until September 1973 when it was moved to the CEGB Llanberis contract in connection with cable-laying; it accompanied some ex-Dolgarrog wagons there.