Gauge: 3ft (915mm) and 1ft 11½in (600mm)
The Gorseddau Tramway was an 8 mile line, built in 1857 to bring slate to the harbour at Porthmadog. Following closure in 1872, it reopened as the Gorseddau Junction and Portmadoc Railway, finally closing by 1892.
The 3 foot gauge Gorseddau Tramway was built in the slate boom years after the Crimean War. Completed in 1857 it linked the quarry and its village of Gorseddau to Portmadog, eight miles away. Quarry access to the Tramway was via an incline, from where the line went to an impressive mill, unusual in having several floors, for finishing the slate as roofing material or slabs. At Tremadog the Tramway joined the route of the old, disused Portmadoc and Penmorfa Railway, built in the 1830s to serve an ironstone mine, which used the 3 foot gauge Portmadoc Cob tramway made redundant by the Festiniog Railway. At Portmadog the Tramway left the old route to make its more direct way to join the Festiniog tracks at the harbour.
One of the best engineered tramways, the Gorseddau was the least used. Like the Penrhyn and Dinorwic railways it was the private line of the quarry. It did carry goods up to the quarry village but never passengers, at least not officially. Gorseddau Quarry’s very brief career was ended within ten years.
In 1875 the defunct line was relaid as the Gorseddau Junction and Portmadoc Railway with a gauge of 1ft 11½in and extended four miles to serve the newly opened Prince of Wales Quarry. A De Winton locomotive, Pert, was used, the only one to run across open country rather than in a quarry. This venture was defunct by 1892.