Air link: building London's elevated light-rail extension

Abstract

The Docklands Light Railway in London has been extended to London City Airport, providing an essential public transport connection between the airport and the London Underground rail network. This paper describes the design and construction of the challenging 4·4 km, twin-track extension— two-thirds of which had to be built above congested urban space on a viaduct—and its four new stations. The viaduct typically consists of post-tensioned concrete segments with span lengths of up to 37 m, with three longer spans being built using the balanced-cantilever method.