Pont-y-Cafnau
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The Pont-y-Cafnau (Welsh, meaning ''bridge of troughs''), sometimes written ''Pont y Cafnau'' or ''Pontycafnau'', is a long
iron Iron () is a chemical element with symbol Fe (from la, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, right in f ...
truss A truss is an assembly of ''members'' such as beams, connected by ''nodes'', that creates a rigid structure. In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so that the assembl ...
bridge over the
River Taff The River Taff ( cy, Afon Taf) is a river in Wales. It rises as two rivers in the Brecon Beacons; the Taf Fechan (''little Taff'') and the Taf Fawr (''great Taff'') before becoming one just north of Merthyr Tydfil. Its confluence with the R ...
in
Merthyr Tydfil Merthyr Tydfil (; cy, Merthyr Tudful ) is the main town in Merthyr Tydfil County Borough, Wales, administered by Merthyr Tydfil County Borough Council. It is about north of Cardiff. Often called just Merthyr, it is said to be named after Tydf ...
,
Wales Wales ( cy, Cymru ) is a Countries of the United Kingdom, country that is part of the United Kingdom. It is bordered by England to the Wales–England border, east, the Irish Sea to the north and west, the Celtic Sea to the south west and the ...
. The bridge was designed by
Watkin George Watkin George (1759-1822) was an carpenter, engineer and ironmaster from Trevethin in Monmouthshire. He rose from humble beginnings as a carpenter to have a major influence on ironworks at Cyfartha and Pontypool and is responsible for the design ...
and built in 1793 for his employer, the
Cyfarthfa Ironworks The Cyfarthfa Ironworks were major 18th- and 19th-century ironworks in Cyfarthfa, on the north-western edge of Merthyr Tydfil, in South West Wales. The beginning The Cyfarthfa works were begun in 1765 by Anthony Bacon (by then a merchant in Lo ...
, to support both a tramway and an aqueduct to carry limestone and water into the works. A Grade II*
listed building In the United Kingdom, a listed building or listed structure is one that has been placed on one of the four statutory lists maintained by Historic England in England, Historic Environment Scotland in Scotland, in Wales, and the Northern Irel ...
and
Scheduled Ancient Monument In the United Kingdom, a scheduled monument is a nationally important archaeological site or historic building, given protection against unauthorised change. The various pieces of legislation that legally protect heritage assets from damage and d ...
, the Pont-y-Cafnau is the world's earliest surviving iron
railway bridge A bridge is a structure built to Span (engineering), span a physical obstacle (such as a body of water, valley, road, or rail) without blocking the way underneath. It is constructed for the purpose of providing passage over the obstacle, whic ...
.


History

The Cyfarthfa Ironworks were founded in 1765 and grew to the world's largest
ironworks An ironworks or iron works is an industrial plant where iron is smelted and where heavy iron and steel products are made. The term is both singular and plural, i.e. the singular of ''ironworks'' is ''ironworks''. Ironworks succeeded bloomeri ...
by the early 19th century. In 1771, the works obtained the right to quarry
limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...
from the
Gurnos Gurnos is a community of Merthyr Tydfil County Borough in Wales, United Kingdom. It consists principally of the Gurnos Estate. The population in 2011 5,280. Background The Gurnos Estate is a large housing estate established by Merthyr Tydfil Coun ...
Quarry for use in the works'
blast furnaces A blast furnace is a type of metallurgical furnace used for smelting to produce industrial metals, generally pig iron, but also others such as lead or copper. ''Blast'' refers to the combustion air being "forced" or supplied above atmospheric p ...
, and a gauge tramway was built between 1792 and 1793 to carry the limestone from the quarry into the plant. Pont-y-Cafnau is situated shortly downstream of the confluence of the Taff Fawr and the Taff Fechan to form the Taff. A
weir A weir or low head dam is a barrier across the width of a river that alters the flow characteristics of water and usually results in a change in the height of the river level. Weirs are also used to control the flow of water for outlets of l ...
had previously been built upstream of the plant on each river, and
leat A leat (; also lete or leet, or millstream) is the name, common in the south and west of England and in Wales, for an artificial watercourse or aqueduct dug into the ground, especially one supplying water to a watermill or its mill pond. Other ...
s were built to convey water into the works. The leat from the Taff Fawr was conveyed in a cast iron elevated aqueduct which ran along the north bank and crossed the Taff Fechan before crossing the Taff at Pont-y-Cafnau and entering the works to power a 50-foot cast iron water wheel known as Aeolus. The leat from Taff Fechan was at ground level and again crossed the Taff at Pont-y-Cafnau. This supplied water to the Cyfarthfa brick works.Rowson, Stephen & Wright, Ian. The Glamorganshire and Aberdare Canals, Black Dwarf Publications 2001, 65,69 The three levels of Pont-y-Cafnau thus carried the elevated Taff Fawr leat, the tramway and Taff Fechan leat across the
Taff River The River Taff ( cy, Afon Taf) is a river in Wales. It rises as two rivers in the Brecon Beacons; the Taf Fechan (''little Taff'') and the Taf Fawr (''great Taff'') before becoming one just north of Merthyr Tydfil. Its confluence with the ...
. The bridge was built between January and June 1793, replacing a previous wooden structure, and is the world's oldest known iron railway bridge. The elevated trough carrying the Taff Fawr leat was removed by 1850, having been replaced by a leat along the south bank of that river.


Design

The present bridge was designed by Watkin George. George had been trained as a carpenter, but in 1792 became the chief engineer of the ironworks and a partner in the business. The bridge is composed of two
cast iron Cast iron is a class of iron–carbon alloys with a carbon content more than 2%. Its usefulness derives from its relatively low melting temperature. The alloy constituents affect its color when fractured: white cast iron has carbide impuriti ...
A-frame An A-frame is a basic structure designed to bear a load in a lightweight economical manner. The simplest form of an A-frame is two similarly sized beams, arranged in an angle of 45 degrees or less, attached at the top, like an uppercase lette ...
trusses A truss is an assembly of ''members'' such as beams, connected by ''nodes'', that creates a rigid structure. In engineering, a truss is a structure that "consists of two-force members only, where the members are organized so that the assembla ...
supporting a rectangular 2-foot by 6-foot-2-inch cast iron trough. This lower trough carried the Taff Fechan leat and acts as a
girder A girder () is a support beam used in construction. It is the main horizontal support of a structure which supports smaller beams. Girders often have an I-beam cross section composed of two load-bearing ''flanges'' separated by a stabilizing ' ...
supporting the plates acting as the railway
sleepers ''Sleepers'' is a 1996 American legal crime drama film written, produced, and directed by Barry Levinson, and based on Lorenzo Carcaterra's 1995 book of the same name. The film stars Kevin Bacon, Jason Patric, Brad Pitt, Robert De Niro, Dustin H ...
, into which the rail chairs are integrally cast. Wooden uprights were attached to the iron risers that passed through the apex of each of the A-frames and these supported the upper trough carrying the Taff Fawr leat. Reflecting its designer's roots in carpentry, the members composing the trusses are joined by dovetail and
mortise and tenon A mortise and tenon (occasionally mortice and tenon) joint connects two pieces of wood or other material. Woodworkers around the world have used it for thousands of years to join pieces of wood, mainly when the adjoining pieces connect at right ...
joints commonly used in wooden structures.


Heritage

On 22 August 1975, the bridge was listed as a Grade II*
listed building In the United Kingdom, a listed building or listed structure is one that has been placed on one of the four statutory lists maintained by Historic England in England, Historic Environment Scotland in Scotland, in Wales, and the Northern Irel ...
(reference number 11408). It is also listed as a
Scheduled Ancient Monument In the United Kingdom, a scheduled monument is a nationally important archaeological site or historic building, given protection against unauthorised change. The various pieces of legislation that legally protect heritage assets from damage and d ...
(reference number GM424). It has been refurbished by the local authority and is used as a
footbridge A footbridge (also a pedestrian bridge, pedestrian overpass, or pedestrian overcrossing) is a bridge designed solely for pedestrians.''Oxford English Dictionary'' While the primary meaning for a bridge is a structure which links "two points at a ...
.


See also

* Gaunless Bridge, an iron railway bridge, built by Stephenson in 1823, and the first iron bridge to be built for a railway, rather than a tramway. *
Old Iron Bridge, Merthyr Tydfil The Old Iron Bridge of 1800, originally known simply as Merthyr Bridge before 1809, in Merthyr Tydfil, South Wales, was a cast-iron bridge across the River Taff. Although an important early example of iron bridge-building and well known as a loc ...
*
List of bridges in Wales This list of bridges in Wales lists bridges of particular historical, scenic, architectural or engineering interest in Wales. Road and railway bridges, viaducts, aqueducts and footbridges are included. List Bridges are listed under the names us ...


References

{{good article Archaeological sites in Merthyr Tydfil Cafnau, Pont-y-Cafnau Scheduled monuments in Wales Cafnau, Pont-y-Cafnau Cafnau, Pont-y-Cafnau Cafnau, Pont-y-Cafnau Grade II* listed buildings in Merthyr Tydfil County Borough 4 ft gauge railways in Wales Bridges over the River Taff 1793 establishments in Great Britain Bridges in Merthyr Tydfil