Stonehouse Viaduct.

Recorded on 19th May 2021 Only Me (Alie), Took a wander over to Stonehouse Viaduct. Once was the highest in Scotland... Bit of info below... The viaduct was officially taken out of service on 16th September 1968. The Caledonian Railway completed extensions to its mid-Lanarkshire and Ayrshire system in 1905 under the powers of Parliamentary Acts from 1896 and 1897. One of the new routes connected the company’s Lesmahagow branch, about a mile north of Larkhall, with the Stonehouse branch, a distance of about 4½ miles. Opened as a single line, the structures were constructed to eventually accommodate two tracks. The River Avon was traversed by two outstanding viaducts. The more southerly, at Stonehouse, comprised eight equal spans of 145 feet, carrying the line for 407 yards at a height of 158 feet whilst the other, to the west of Larkhall, was shorter but more imposing, being 285 yards long and reaching 175 feet above the water. This made it the highest railway bridge in Scotland. It consists of six spans of open web steel girders supported on masonry piers, with three spans of 106ft 9in, two of 140ft 9in and one of 174ft 9in. The viaduct is straight but climbs on a gradient of 1:80. The total weight of its steelwork is 1,399 tons whilst the quantity of masonry and concrete used is 20,192 cubic yards. All the pier foundations are on rock at depths varying from 25ft to 60ft below ground. No construction difficulties were experienced except with pier 7 where the rock was 59ft below the surface, the overlying material being saturated mud. This foundation, which is 50ft long by 36ft wide, was taken out in two sections and had to be close-timbered for the full depth and kept dry by constant pumping. Above their foundations, the piers and abutments consist of solid stonework, built in courses ranging in thickness from 24in at the bottom to 15in under the granite girder-bearing blocks. The facing of the piers consists of squared masonry, bonded into the interior which is filled with rough rubble thoroughly grouted in cement mortar. The top four courses of each pier consist of solid ashlar. The pier tops are 11ft long and 24ft wide, with a longitudinal batter of 1:40; in the transverse section the batter is 1:24 for the piers up to 100ft in height. The stone used to build the piers was obtained from a quarry half-a-mile away whilst the girder-bearing blocks are of Norwegian granite. To assist in the piers’ erection, a timber service bridge was built at a height of 83ft above the river, on which building materials were lowered and taken forward. Thanks for watching Cheerio, Alie.