Ancient Monuments

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Cegin Viaduct (Penrhyn Railroad)

A Scheduled Monument in Bangor, Gwynedd

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Latitude: 53.2298 / 53°13'47"N

Longitude: -4.1098 / 4°6'35"W

OS Eastings: 259265

OS Northings: 372388

OS Grid: SH592723

Mapcode National: GBR 5Q.0J54

Mapcode Global: WH547.V24R

Entry Name: Cegin Viaduct (Penrhyn Railroad)

Scheduled Date: 27 July 2004

Source: Cadw

Source ID: 4153

Cadw Legacy ID: CN380

Schedule Class: Transport

Category: Viaduct

Period: Post Medieval/Modern

County: Gwynedd

Community: Bangor

Traditional County: Caernarfonshire


The monument is a well-preserved example of an early railroad bridge, built between 1798 and 1800 to carry the Penrhyn railroad over the lower reaches of the Afon Cegin. It is likely that the Cegin Viaduct is the oldest known multi-arched railway bridge to survive above ground in Wales and possibly the world. It comprises a stone-built three arched bridge measuring about 26m in length between each abutment and 5m in width and 3.2m in height. Each arch has a span of between 5m and 6m and height of about 1.8m. The arches are well constructed, with each voussoir being of similar size and shape and with even soffits. There is a slate-roofed sluice at the N end (measuring 1.2m in width and 2m in height) and an artificial pitched stone surface to the riverbed beneath the bridge and extending E, immediately upstream.

The earliest known record of the bridge is found in an estate map of 1803, which shows the Penrhyn railroad crossing the Afon Cegin on the site of the present bridge. Work had begun on the railroad in 1800 and comprised laying a then very ambitious length of cast iron rails (designed for use with double-flanged wheels). This edge railway was a longer construction than those already in existence in the South Wales valleys and, as such, marks an important stage in the evolution of the modern railway system. The bridge was almost certainly constructed sometime between 1798 and 1800 and it has been suggested as typical of the work of a local architect and builder, John Foulkes (c. 1765 - 1850). The new Penrhyn Quarry Railway (with a new bridge, the pillars of which still stand immediately to the E, carrying a timber footbridge) superceded the Penrhyn railroad in 1879.

The monument is of national importance as a rare and well-preserved example of an early railroad viaduct. The structure may be expected to contain archaeological information in regard to chronology and building techniques.

The area to be scheduled comprises the remains described and an area around them within which related evidence may be expected to survive. It is irregular and measures 34m from N to S by 5m transversely.

Source: Cadw

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