Part of a sandstone core removed from Ballochmyle Viaduct (1846 – 1850) during upgrade works carried out by Carillion for the client Network Rail in 2013 – 2014. The core is 62 mm in diameter and 270 mm long. The stone which was locally quarried is described by the British Geological Survey as “New Red Sandstone (Permian) red desert sandstone showing large-scale aeolian (wind-blown) dune-bedding”. The stone is red in colour due to a coating of haematite, an iron oxide.
The chief engineer for the viaduct was the eminent Scottish civil engineer John Miller.
The stone blocks used in construction varied in size, one larger block was measured on site at 2.2 m x 0.8 m x 0.6 m giving a volume of 1.056 cum. The density of the core was measured to be 2.24 t/cum which suggests a weight of 2.37 tonnes (2.6 tons) for the block. This stone can be seen towards the bottom right of Image 3 (showing Provost Jim Todd (L) and ICE President Geoff French immediately before the unveiling). When completed in 1849 the main arch of the Ballochmyle Viaduct with a masonry span of 181 ft (55 m), and height from mean water level to parapet top of 177 ft (54 m), was believed to be the world’s largest on a railway and is still the largest such in the UK. An idea of its size can be imagined now from the fact that the height of its rails above the river is significantly greater than at the Forth Bridge [158 ft (48 m)]. The reference regarding sandstone type is http://britgeoheritage.blogspot.co.uk/2013/12/ballochmyle-quarry-mauchline-ayrshire.html.
For a description of the works by Professor Paxton click here.
From around 1830 Miller (the chief engineer for the viaduct) formed a close friendship with David Octavius Hill the Scottish painter and pioneer of photography. At that time, before the age of photography, Hill was a practicing artist. Miller commissioned Hill to paint a number of pictures of key aspects of the railways he was designing. Subsequently, Miller took a keen interest in photography and he and Hill together created the Photographic Society of Scotland in 1856. One painting commissioned by Miller is of the Ballochmyle Viaduct (see https://ice-museum-scotland.hw.ac.uk/wp-content/uploads/doh_ballochmyle.jpg).
The viaduct was featured in the Tom Cruise film Mission Impossible (1996). For a clip see https://www.youtube.com/watch?v=7UghfVQVJoE.