Float viaduct—a high-speed rail bridge replacement

Abstract

The replacement of a strategic bridge at a remote, environmentally sensitive location on the UK's main west-coast railway in just five days required a tremendous amount of advance planning. The 135 year old Float viaduct crossing the upper reaches of the River Clyde needed to be replaced as part of Railtrack's upgrade of the busy route to suit 200 km/h electric trains. Working under a fixed-price design-and-construct contract, Carillion and Scott Wilson opted to move both the old bridge deck out and the new bridge deck in by lifting rather than sliding. Apart from the first span initially refusing to move, the meticulously planned project went without a hitch and was completed well within the five-day track possession.