The Ordsall Chord, a viaduct that will help make possible an upgraded rail hub project in northern England, includes a single network tied arch that spans the River Irwell, in Manchester. The Chord’s twin suspension girders dip beneath the tracks before rising slightly and extending horizontally along the rail line to support the remainder of the viaduct. Network Rail
Manchester, England, plans to build the first network arch bridge to be used on a rail line in the United Kingdom as part of its plan to significantly upgrade the rail system in Northern England.
March 4, 2014—Last month the United Kingdom’s chancellor of the exchequer, the cabinet minister in charge of finance, announced the official launch of a £600-million (U.S.$1-billion) upgraded rail hub in Northern England. One of the crucial first steps in realizing this project is the approximately £120-million (U.S.$199.6-million) two-track viaduct known as the Ordsall Chord, a new rail line that will connect Manchester’s Piccadilly and Victoria rail stations and establish an additional route by which trains can pass over the River Irwell. The Ordsall Chord will have to carefully negotiate a cluster of 10 historical infrastructure crossings. Its most prominent feature will be a 90 m long, 12 m wide, 15.5 m high network arch bridge—a tied arch with inclined hangers that crisscross each other at least twice. This would be the first rail bridge in the United Kingdom to utilize a network arch design.
“The Northern Hub is essentially a number of critical infrastructure enhancements that we have brought together under one package to deliver more capacity and journeys in the north of England,” says Hassard Stacpoole, the Network Rail spokesperson for the Northern Hub project. “It is all about releasing capacity on the existing network.”
Within Manchester, the Northern Hub project will upgrade track and signaling between the city’s Piccadilly station and Oxford Road, a key central rail artery in the city, increasing capacity for both passenger and freight services. The curved Ordsall Chord viaduct will free capacity for increased rail services through the city and relieve an existing bottleneck at Piccadilly station.
The work on the Ordsall Chord and along the Piccadilly-Oxford road artery nearby will enable trains to be diverted around Manchester and “transform how services operate” within the city and region, Stacpoole says. The link will also facilitate the construction of future phases of the Northern Hub upgrade, he adds.
Although the Ordsall Chord will “pass through one of the most important historic sites in the evolution of the railway,” according to a Design and Access Statement about the project released by Network Rail in September, the benefits of the new line to future infrastructure needs are worth the impact of its construction.
The curved line of the steel and concrete network arch bridge “unites different structural approaches, becoming the conceptual form of a flowing ribbon, tapered at both ends,” according to the statement. The single arch spans the river, at which point its twin suspension girders dip beneath the tracks before rising slightly and extending horizontally along the rail line to support the remainder of the viaduct structure that will continue to carry the rail line. This remaining structure is a 125 m long, half-through bridge, its main girders flanking the deck.
The £120-million (U.S.$199.6-million) two-track Ordsall Chord will
connect Manchester’s Piccadilly and Victoria rail stations and
create an additional route by which trains can pass over the River
Irwell, relieving a rail bottleneck at the station at Piccadilly. The
viaduct will carefully negotiate a cluster of historic infrastructure
crossings at this location. Network Rail
The fluidity and delicacy of the network arch design is intended to be a visually arresting element that pays homage to the arches of the nearby Stephenson’s Bridge, a structure listed as Grade I (of “exceptional interest”) by English Heritage, the organization responsible for historic preservation in the United Kingdom. The arch is also meant to serve as a recognizable landmark in its own right.
In addition to Stephenson’s Bridge, there are nine listed structures directly within the area of the Ordsall Chord that are considered Grade II (“of particular importance,” higher than Grade I). They are the 1830s Viaduct; the Water Street Bridge; the Zig Zag Viaduct and Water Street Bridge; the Girder Bridge; the Castlefield Viaduct 1845 Brick Bridge; the Castlefield Viaduct and Cast Iron Bridge; the Central Railway Viaduct; the Southern Railway Viaduct and Colonnade; and the Northern Railway Viaduct. Impacts on most of these structures must be avoided, but some impact will be inevitable. For example, three bridges will be demolished: a nondescript bridge of no historical value as well as the listed Girder Bridge and Castlefield Viaduct Cast Iron Bridge. In addition, the Zig Zag Viaduct will be partially demolished and the upper portions of the 1830s Viaduct will be impacted by strengthening its piles and arches.
Currently, the design of the line is awaiting planning permission from the Department of Transport, which is anticipated in late 2014. Construction of the viaduct could begin shortly thereafter, with opening anticipated by 2016.
Once the Northern Hub upgrades are complete, as many as 700 additional trains will be able to operate across Northern England each day, according to Network Rail. This will provide capacity for an additional 44 million passengers annually.
The line will be electrified as part of a separate, but concurrent, project to electrify trains throughout northern England.