Viaduct at Slade, Devon, mid-19th century.

UNITED KINGDOM - JUNE 10: Hand-coloured lithograph of a steam locomotive on the Blatchford Viaduct, South Devon Railway. The 101-foot high trestle viaduct with stone piers was one of a series of viaducts of similar design built by Isambard Kingdom Brunel (1806-1859) for the South Devon Railway linking Exeter and Plymouth, which was completed in 1849. Although inexpensive to build, the timber viaducts had a short lifespan, and needed to be replaced by stone or brick structures. This one was replaced in 1893. The South Devon Railway which opened in 1846 and stretched for 53 miles. It was powered by winding engines and pneumatic power but this method of traction was given up in favour of locomotives. The Railway was built as a Broad Gauge railway, but was converted to standard gauge at the end of the 19th century. (Photo by SSPL/Getty Images)