Whilst in Porthmadog with the family visiting the WHR(P), I went to look briefly at the route of the Gorseddau Tramway in the town. Time didn't allow wider exploration of this historic slate tramway but I hope one day to return and walk more of the route.
The Gorseddau had a convoluted history and spent most of its physical existence in states of quiet decay. Opened around 1857 as a 3' gauge horse worked tramway, it was older than many better-known slate lines such as the Talyllyn, the Corris Railway, the Croesor Tramway and even than the Cambrian main line through Portmadoc, as the town's name was spelt in those days.
The Gorseddau Tramway was promoted and built by entrepreneurs hoping to make a killing by developing new slate quarries in the mountains south of Beddgelert. Spurred by the profits achieved at better sited quarries, they built a large mill and the streets of a small village in an empty cŵm high in the hills. To move the finished slate they adopted the progressive method of an unusually well engineered narrow gauge railway – the Gorseddau Tramway. At Tremadoc near Portmadoc, the Gorseddau connected to and ran over the disused remains of the even earlier Tremadoc Tramway (one source names it the Portmadoc & Penmorfa Railway), a 1½ mile long horse tramway of 3' gauge dating from the late 1830s originally carrying ironstone to the wharves at Portmadoc. The slate was to be brought down by the Gorseddau for dispatch by ship from Portmadoc alongside wagons from the competing Festiniog, itself still horse worked at the time.
It was an ambitious social and economic scheme to create a profitable local slate industry from scratch. Sadly for the Gorseddau Tramway, the quarry owners, and especially for their shareholders and the inhabitants of the desolate new village, the prospecting (assuming the promoters had done any) had been inadequate. The slate at Gorseddau was poor quality and the quarries were unproductive. The Tramway, its traffic even at its peak in 1860 being counted in wagons per week rather than the hoped-for wagons per day, was out of use by 1870.
Nevertheless in 1872-75 during a further Welsh slate boom, other local quarry owners bought the Gorseddau, rebuilt it as a 2' gauge line under the name The Gorseddau Junction & Portmadoc Railway and extended it to their quarries at Prince of Wales Quarry. They used steam traction in the shape of a solitary De Winton vertical boilered loco, a primitive design even then. Slate from the Gorseddau could now be carried either by main line train (an interchange yard was planned with the Cambrian, though it never amounted to more than a siding) or by ship (the new Gorseddau reached the wharves via the tracks of the Croesor Tramway). But these quarries proved little more productive; the loco was soon replaced by horses and then by manpowered propulsion of single wagons. By 1892 the Gorseddau Junction had lapsed back into sleep, and it had been dismantled before the end of the 19th Century.
The short section of its route pictured here was used for a fourth time between 1903 and 1907 as part of the Moel y Gest quarry tramway. Although that tramway too was soon abandoned, I believe this section may have remained in situ until the 1950s – any clarification would be welcome.
"The Slate Railways of Wales", Alun John Richards, pub. 2001 by Gwasg Carreg Gwalch ISBN 0-86381-689-4
Much more historical detail, present-day pictures and an extensive Bibliography at the Bangor/WHR page about the Gorseddau.
FR Heritage Wiki about the Gorseddau Junction.
"The Slate Industry of North and Mid Wales" at penmorfa.com has images and history on Gorseddau Quarry and Prince of Wales Quarry.
Iain Robertson's superb pictures of Gorseddau Quarry and Prince of Wales Quarry.
Ron Fisher's pics of the route of the Gorseddau in the 1960s and 2000s.
Wiki: Gorseddau Tramway and the Gorseddau Junction and Portmadoc.