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‹ Cof Cymru: National Historic Assets of Wales, Wales

Cof Cymru: National Historic Assets of Wales · Wales

Strainer arches and retaining walls

Llanllyfni, Gwynedd, Wales

The record

Designation
Listed building, Grade II
Broad class
Industrial
Date of designation
21 July 2000
Locality
Nantlle
Community
Llanllyfni
Unitary authority
Gwynedd
Country
Wales
Coordinates
53.05578, -4.23691
Cadw reference
23728

Slide toward Today to fade the historical sheet and see the modern map underneath.

David Rumsey Map Collection, Stanford Libraries

Shown on 5 historical map sheets, the earliest the 1795 "To Sir Watkin Williams-Wynn Bart ... the map of the six counties of North Wales is most humbly inscribed by his obedient humble servant" (Llyfrgell Genedlaethol Cymru – The National Library of Wales).

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This record in Cadw's own full report ↗

Cadw's description

Located to the south of Pen-y-bryn, the strainer arches and walls retain the slate waste tips flanking the route of the Dorothea Quarry branch of the former Nantlle Railway.

The Nantlle Railway opened in 1828 as a 3ft 6in (1.07m) gauge horse-drawn tramway to take slates from the Nantlle Vale quarries to the port at Caernarfon. The Dorothea Quarry opened in 1829 and remained in continuous production until 1970; the branch of the tramway/railway flanked by the strainer arches and retaining walls, which probably date to the late C19, connected the main line of the tramway to the main Dorothea Quarry.

Two very high battered retaining walls built of coursed slate slabs with pair of slate strainer arches, arched above and below with slate voussoirs, holding the walls apart.

Listed as substantial and distinctive structures associated with the former Nantlle Railway, an important early horse-drawn tramway, crucial to the rapid expansion of the Dorothea Slate Quarry during the C19.

Nearby in the register

Other entries of the same register within about three miles of this one, by straight line.

Designated Historic Asset GIS Data, The Welsh Historic Environment Service (Cadw), 2026-09-07, licensed under the Open Government Licence http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/ Cadw, the Welsh Historic Environment Service · Open Government Licence v3.0
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