1.

Gorseddau Slate Quarry (NPRN 40557) was first opened in 1807, but its main period of working was between 1854 and 1857, when it was developed by the Bavarian mining engineer Henry Tobias Tschudy von Ulster. The visible remains include tiered workings and spoil tips set into a south-west facing hillside. It includes the remains of an incline, several ruined structures and a workers' village.
This tramway was built during the main phase of working in 1854-7, but was dismantled by 1920. It ran W from Gorseddau Slate Quarry, to Gorseddau Junction, turning SW towards Porthmadoc. At the NGR given, the former tramway consists of a wide grassy track 2.3m wide. From here it runs east then curves north to the bottom of a quarry incline. In the opposite direction it is now a vehicle track as far SW as Tyddyn Mawr farm.
Additional source:
Ordnance Survey record SH54NW26.
Associated with Ynyspandy slate mill (40572).

Recorded as part of RCAHMW Uplands Initiative Project, W B Horton, H & H, 11/03/2013.

2.

The railway systems serving the two quarries and connecting them to Porthmadog harbour exemplify different approaches to construction – the well-engineered horse-and gravity-worked line of 1857 on a constant down-gradient to assist movement of the load, by James Brunlees (1816–1892) to Gorsedda quarry, and the very light and cheaply-built locomotive-worked formation of 1875 to Prince of Wales quarry, the Gorseddau Junction & Portmadoc Railways. Brunlees had already worked on the Londonderry and Coleraine Railway and on the Ulverston and Lancaster. Once he had completed the Gorsedda contract, Brunlees sent his assistant Daniel Makinson Fox (1830-1918) to survey the challenging São Paulo Railway in Brazil. Fox spent most of the rest of his career in Brazil.

Statement of Significance:

The Gorsedda railway formed the link between the quarry, the Ynysypandy slate-slab mill and the sea, and survives as a relict component of this important slate-quarrying landscape. One of the second-generation horse- and gravity-worked systems serving the slate industry, it is also significant as the work of Sir James Brunlees, a major Victorian engineer who worked in Brazil, Switzerland and New Zealand. The Gorseddau Junction & Portmadoc Railways is a lightly-engineered system that reflects the short-lived optimism in the slate industry in the 1870s, and evolving views about the construction of inexpensive locomotive-worked industrial railways. 

In both cases the railways serve to emphasise the functional linkages in a dispersed industrial-cultural landscape. 

This site is part of the Slate Landscape of Northwest Wales World Heritage Site, Component Part 4: Gorseddau and Prince of Wales Slate Quarries, Railways and Mill. Inscribed July 2020. 

Sources:

Louise Barker & Dr David Gwyn, March 2017. Gwynedd Slate Industry Transport Routes. (Unpublished Report: Project GC401 for Gwynedd Archaeological Trust) 
Tirwedd Llechi Gogledd Orllewin Cymru / The Slate Landscape of Northwest Wales. Nomination as a World heritage Site (Nomination Document, January 2020) 
Wales Slate World Heritage Site https://www.llechi.cymru/

Hannah Genders Boyd, RCAHMW, January 2022

Site Record

Gorseddau Slate Quarry, Tramway