line commenced in July 1838; work to build the ornate viaduct began during the following year. It was designed by the principal engineer for the line, John Urpeth Rastrick, in association with the architect of the London to Brighton railway, David Mocatta. The contractor appointed for its construction was Benjamin Baylis. The total cost of the viaduct's construction reportedly came to £38,500 (equivalent to about £3.3 million in 2022). The viaduct was designed as a relatively elegant structure, being around in length and carrying a straight line over 37 identical arches. Each of these semi-circular arches had a span of and was supported upon tapered red-brick piers. Each pier was almost divided into two separate halves by vertical voids, capped by semi-circular rings at the top and base, as a weight-saving measure. This approach is credited with giving the structure a relatively slender appearance. The foundation of each pier is provided with two courses of inclined footings, which have a total depth of just over . The viaduct is predominantly composed of traditional red bricks and smooth limestone. The contrast between the two materials effectively highlights the deck and upper elements of the structure, although the limestone has been subjected to considerable weathering and staining since its original installation. The brickwork and the limestone elements have been replaced over time to maintain the structure's integrity, extend its operational life, and restore its appearance to better resemble its original state. At its highest point, the Ouse Valley Viaduct is above the river beneath it. It has been estimated that around 11 million bricks, many of which had been shipped across the English Channel from the Netherlands to Newhaven and Lewes, in addition to some locally produced bricks, were used for the structure. Furthermore, Caen stone was also brought from Normandy in France; this material was used for the classically balustraded parapets, string courses, pier caps and the four small rectangular Italianate pavilions. Building materials were transported to the construction site on barges up the Ouse River Navigation. At each end of the abutment is an ornamental square open tower, the brickwork of which is faced with stone from Heddon Quarries near Newcastle-upon-Tyne. Opening The Brighton Main Line was opened in two sections because completion was delayed by the need to construct some major earthworks. The viaduct was officially opened when the section between Norwood Junction and Haywards Heath was opened on