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Cof Cymru: National Historic Assets of Wales · Wales

Incline and Drumhouses

Llanddeiniolen, Gwynedd, Wales

A Grade II listed building in Gilfach Ddu, Caernarfon, Llanddeiniolen, Gwynedd, designated on 4 November 1999.

Ordnance Survey six-inch map, 2nd edition (1888–1913) covering the location of Incline and Drumhouses, Llanddeiniolen, Gwynedd, with a pin at the register's coordinates
Ordnance Survey six-inch map, 2nd edition (1888–1913), covering this location. Courtesy of the National Library of Scotland. The pin is ours, placed from the register's coordinates.

The record

Designation
Listed building, Grade II
Broad class
Industrial
Date of designation
4 November 1999
Locality
Gilfach Ddu
Town
Caernarfon
Community
Llanddeiniolen
Unitary authority
Gwynedd
Country
Wales
Coordinates
53.12341, -4.11528
Cadw reference
22661

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

David Rumsey Map Collection, Stanford Libraries

5 historical maps cover this location, the earliest the 1896 map "Sheet 7. Ordnance Survey of England and Wales." (David Rumsey Map Collection, Stanford Libraries).

Historical maps covering this location

  • 1896 · Sheet 7. Ordnance Survey of England and Wales. (David Rumsey Map Collection, Stanford Libraries)
  • 1899 · 106 Bangor (Hills) (David Rumsey Map Collection, Stanford Libraries)
  • 1899 · 106 Bangor (Outline) (David Rumsey Map Collection, Stanford Libraries)
  • 1901 · Sheet 9 and 10. (David Rumsey Map Collection, Stanford Libraries)
  • 1919 · Sheet 41. Anglesey. (David Rumsey Map Collection, Stanford Libraries)

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This record in Cadw's own full report ↗

Cadw's description

Incline and drumhouses rising from the old floor (now car park of the Welsh Slate Museum) to the top level of the former Vivian Slate Quarry; massive slate retaining wall located immediately to the north of the reconstructed section of incline.

The Vivian Quarry, an open hillside quarry worked on 6 levels, formed part of the Dinorwic Quarry, first established in 1787, taking over existing workings in the area, the first incline being built in 1789. By the 1830s there was a tramway system on each terrace of the quarry, steam locomotives being introduced in the 1870s. The eventual scale of the quarry was such that its output of c100,000 tons p.a. in the late 1890s put in on a par with Penrhyn, representing almost a quarter of the total production of Welsh slate. The quarry finally closed in 1969. The first drumhouse and lowest pitch of the incline above the former Padarn Railway has been restored to full working order (based on the form of the incline in 1910) by the Welsh Slate Museum and is not included on this List.

Incline runs in 5 tandem pitches, the lower 3 (including the section reconstructed by the Slate Museum) with much of the track and gear intact. The 4 unrestored drumhouses are of rubblestone and slate slab construction with gable-ended slate roofs. All retain their brake-drums and cabling, the brake mechanisms to the lower inclines being of massive cast-iron construction, operated via spur gears and "ship's wheel" controls with elaborate remote control crimp sprags. Double drumhouse on top level.

Included as a remarkably well-preserved incline with drumhouses and counter balances forming an integral part of the former Vivian Slate Quarry and particularly important for the impressive physical evidence it provides for the distribution of slate away from the quarry.

Scheduled Ancient Monument (198).

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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