The Usk Railway Bridge is a railway viaduct in

Newport city centre Newport city centre is traditionally regarded as the area of Newport, Wales bounded by the west bank of the River Usk, the George Street Bridge, the eastern flank of Stow Hill and the South Wales Main Line. Most of the city centre is containe ...

Wales Wales ( cy, Cymru ) is a country that is part of the United Kingdom. It is bordered by England to the east, the Irish Sea to the north and west, the Celtic Sea to the south west and the Bristol Channel to the south. It had a population in ...

. It crosses the River Usk in an east—west direction, carrying the Great Western Main Line. The original bridge was constructed for the

South Wales Railway The South Wales Railway ( cy, Rheilffordd De Cymru) was a main line railway which opened in stages from 1850, connecting the Great Western Railway from Gloucester to South Wales. It was constructed on the broad gauge. An original aspiration was to ...

and designed by the accomplished railway engineer,

Isambard Kingdom Brunel Isambard Kingdom Brunel (; 9 April 1806 – 15 September 1859) was a British civil engineer who is considered "one of the most ingenious and prolific figures in engineering history," "one of the 19th-century engineering giants," and "on ...

. Brunel's viaduct, which was primarily constructed of

creosote Creosote is a category of carbonaceous chemicals formed by the distillation of various tars and pyrolysis of plant-derived material, such as wood or fossil fuel. They are typically used as preservatives or antiseptics. Some creosote types were ...

-treated

timber Lumber is wood that has been processed into dimensional lumber, including beams and planks or boards, a stage in the process of wood production. Lumber is mainly used for construction framing, as well as finishing (floors, wall panels, w ...

, suffered a catastrophic fire near completion, resulting substantial delay and its rebuilding. The redesigned structure used considerably more

wrought iron Wrought iron is an iron alloy with a very low carbon content (less than 0.08%) in contrast to that of cast iron (2.1% to 4%). It is a semi-fused mass of iron with fibrous slag inclusions (up to 2% by weight), which give it a wood-like "grain" ...

in place of wood, and included the first use of the now-common bow-string-shaped girder. This first bridge was opened to traffic during 1850. During the late 1880s, a second bridge was constructed alongside the first, which benefitted from a simpler design in comparison to the first. During the 1910s, the second bridge was extended to accommodate a quadruple track configuration, enabling the original bridge to be retired during 1925. During 2019, the lines across the second bridge were

electrified Electrification is the process of powering by electricity and, in many contexts, the introduction of such power by changing over from an earlier power source. The broad meaning of the term, such as in the history of technology, economic history ...

as part of the 21st Century upgrade of the Great Western Main Line.

History

Origins and predecessors

The origins of the Great Western Railway Usk bridge are closely connected with the early history of the Great Western Railway (GWR) and its renowned chief engineer,

. The directors of the GWR had resolved to construct a trunk route between

London London is the capital and List of urban areas in the United Kingdom, largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary dow ...

and Swansea, running though various cities and major settlements in between. During the 1840s, Brunel, who had been put in charge of surveying and selecting the line's route, arrived in Newport for the purpose of planning how the

would traverse various geographic challenges, which included a means of carrying the line across the River Usk. Brunel decided that a viaduct would be the optimal means of crossing the river and designed such a structure. Possessing eleven spans and stretching to a length of 1,200 ft, this viaduct was largely composed of

, which was treated with

under pressure as to sufficiently weather-proof them against the prevailing conditions of the location. Construction work commenced during 1846. The total cost of the viaduct's construction reportedly exceeded £20,000. However, its extensive use of wood heavily contributed to the bridge's destruction just prior to completion. On 31 May 1848, as the final arch was being put into place, a heated bolt used to

rivet A rivet is a permanent mechanical fastener. Before being installed, a rivet consists of a smooth cylindrical shaft with a head on one end. The end opposite to the head is called the ''tail''. On installation, the rivet is placed in a punched ...

a beam together ignited the flammable creosote; within the space of six minutes, a catastrophic fire had spread across the whole structure, setting the opening back by years. Brunel swiftly redesigned the bridge explicitly to prevent any recurrence of fire. Recognising that starting from scratch would set the line's completion back even longer, he decided to incorporate the remaining structural elements into the new bridge. While some elements continued to use wood,

plates and girders were also adopted; the remaining wooden elements were subject to a different treating method, known as chyanizing. In his redesign of the bridge, Brunel effectively invented the now-common bow-string-shaped girder to replace several of the wooden sections originally used. By 1850, the Usk railway bridge was effectively complete, and the first trains crossed the structure that same. It would be in service for exactly 75 years, being retired during 1925 and dismantled soon thereafter, having been replaced by a newer bridge alongside.

Current bridge

In 1888, the original bridge was supplemented with a second one, which was made largely of stone. Its deck, made of metal, made use of a

lattice Lattice may refer to: Arts and design * Latticework, an ornamental criss-crossed framework, an arrangement of crossing laths or other thin strips of material * Lattice (music), an organized grid model of pitch ratios * Lattice (pastry), an orna ...

, or criss-crossing, design to enable the supporting girders to resist bending forces; it was considered to be of a simpler and more routine design than its predecessor. By 1911, the second bridge had been widened to accommodate the running of four lines across its deck, in anticipation of the first bridge's retirement. During 2019, the tracks across the second bridge were

as part of the 21st Century upgrade of the Great Western Main Line. For several years prior, the bridge was subject to preparatory and improvement works to renew the structure, which included numerous repairs and all exterior surfaces being repainted during temporary closures.

Citations

External links

Image of the Great Western Railway Usk bridge via geograph.org.uk

Usk Railway Bridge via coflein.gov.uk
* {{coord, 51.59113, N, 2.99453, W, region:GB_source:enwiki-osgb36(ST312885), display=title Bridges in Newport, Wales Bridges completed in 1849 Railway bridges in Wales Bridges over the River Usk 1849 establishments in the United Kingdom