page_title: Cornwall Railway viaducts
section_title: Carnon
hierarchical_section_title: Cornwall Railway viaducts / Viaducts from Truro to Falmouth / Carnon
caption_attribution_description: The original timber Carnon Viaduct near Perranwell station on the Falmouth branch in Cornwall.
context_page_description: The Cornwall Railway company constructed a railway line between Plymouth and Truro, England, opening in 1859, and extended it to Falmouth in 1863. The topography of Cornwall is such that the route, which is generally east-west, cuts across numerous deep river valleys that generally run north-south. At the time of construction of the line, money was in short supply due to the collapse in confidence following the railway mania, and the company sought ways of reducing expenditure.
  On the advice of the Victorian railway engineer Isambard Kingdom Brunel, they constructed the river crossings in the form of wooden viaducts, 42 in total, consisting of timber deck spans supported by fans of timber bracing built on masonry piers. This unusual method of construction substantially reduced the first cost of construction compared to an all-masonry structure, but at the cost of more expensive maintenance.
  Replacement of the timber viaducts by all-masonry structures began in the 1870s but a few remained in service until the 1930s.
context_section_description: A Class A viaduct 96 feet (29 m) high and 756 feet (230 m) long on 11 piers. The soft nature of  valley floor meant that some piers had to have a foundation built for them by sinking a temporary caisson and removing the mud within it. It was replaced by a new stone viaduct on 13 August 1933.
  This viaduct crossed Restronguet Creek and the Redruth and Chasewater Railway near its Devoran terminus. This disused railway line now forms part of the Mineral Tramway Trails.
caption: Carnon viaduct
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