Gauge: 1ft 11½in (600mm)
The Croesor Tramway was opened in 1864 from Portmadoc to the head of Cwm Croesor. Eight miles long and 1ft 11½in gauge, the line was built by Hugh Beaver Roberts, proprietor of the Croesor Quarry. The quarry was linked to the tramway by a precipitous 750 foot incline. Unlike earlier tramways the Croesor used chaired T-section rails, mounted on wooden sleepers.
Several other slate quarries were linked to the tramway along the valley to Croesor village. From there, the line ran to Parc incline which dropped the line down onto the flood plain of the Afon Glaslyn. Having crossed the river, it then ran the four miles to Portmadoc harbour. A branch to Beddgelert was planned but never built. Likewise the introduction of locomotives from Portmadoc out to Parc incline also never happened. Like the Nantlle Railway the Croesor Tramway was a rail turnpike with quarry owners paying to run their own wagons along the line and hiring the Tramway’s horses and drivers.
Apart from carrying slate the Croesor Tramway had an important role as a general carrier, transporting vital goods to the otherwise isolated Croesor village, farms and houses in the roadless valley. It fulfilled this role until the 1930s when the line fell into disuse.