The Sankey Viaduct is a railway viaduct in North West England. It is a designated Grade I listed building and has been described as being "the earliest major railway viaduct in the world". In 1826, the Liverpool and Manchester Railway Company (L&MR) was authorised to construct the world's first intercity railway. One obstacle on the selected route between Liverpool and Manchester was the Sankey Valley. The company's principal engineer, George Stephenson, designed the Sankey Viaduct for the double-track railway to traverse the valley and Sankey Canal with sufficient clearance for the masts and sails of the Mersey flats that used the canal. The viaduct was built between 1828 and 1830, although work on the structure did not finish until the middle of 1833. On 15 September 1830, the viaduct was opened along with the Liverpool & Manchester railway. During 2015, Network Rail installed overhead line equipment as part of a wider electrification programme. History Background In 1826, the Act for the Liverpool & Manchester Railway (L&MR), the world's first intercity railway, was passed by Parliament. George Stephenson was the company's principal engineer for the route between Liverpool and Manchester. The route required crossing the Sankey valley west of Newton-le-Willows, about halfway along the line. The Sankey valley contained two obstacles, the Sankey Brook and the Sankey Canal that was constructed to link the St Helens coalfield to the River Mersey. The engineered waterway could be regarded as the first canal built in England since Roman times. To traverse the Sankey Valley, Stephenson had to devise a route for the railway to pass without obstructing barges on the canals and maintain gradients for steam locomotives using the route. The Sankey Brook Navigation Company objected to the Liverpool & Manchester Railway's intended route and insisted that any structure across the valley must provide a minimum clearance of 18.3 meters above the water to allow fully-rigged Mersey flats to pass underneath. Stephenson's solution was to construct an embankment on the west side of the valley, roughly long, and then cross the brook and the canal on a viaduct that met a smaller embankment on the eastern side. Stephenson designed the viaduct in conjunction with Thomas Longridge Gooch, his chief draughtsman. Constructed from yellow sandstone and red brick, the viaduct is of nine round-headed arches carried on piers that incline sharply from the base towards the top. Its form is similar to the traditional