Ballochmyle Viaduct

Ballochmyle Viaduct
Coordinates	55°29′58″N 4°21′45″W / 55.4995175°N 4.3625094°W / 55.4995175; -4.3625094
Crosses	River Ayr
Characteristics
Material	Stone
Height	169 feet (52 m)
Longest span	181 feet (55 m)
No. of spans	7
History
Construction start	March 1846
Construction end	2 March 1848
Opened	9 August 1850
Location

The Ballochmyle Viaduct is the tallest extant railway viaduct in Britain. It is 169 feet (52 m) high, and carries the railway over the River Ayr near Mauchline and Catrine in East Ayrshire, Scotland. It carries the former Glasgow and South Western Railway line between Glasgow and Carlisle.^[1]

Designed by John Miller, the viaduct was built in the 1840s for the Glasgow, Paisley, Kilmarnock and Ayr Railway Company. Work commenced on its construction during March 1846; it was built under contract by Ross & Mitchell and William McCandlish was the resident engineer. It is built of local red sandstone and stronger stone sourced from Dundee was used for the arch rings. On completion on 2 March 1848, the viaduct had the largest masonry arch in the world and remains amongst the largest ever been constructed.

The viaduct was listed in April 1971 and became a Category A listed structure in January 1989. It was designated a "Historic Civil Engineering Landmark" by the Institution of Civil Engineers (ICE) in 2014. Network Rail undertook strengthening work on the viaduct in the 2010s. The Ballochmyle Viaduct is used for passenger and freight traffic through to the present day.