Shani Wallis, TunnelTalk

Battersea and Nine Elms service area

An extension of London's Underground network is a vital element of major redevelopment of London's iconic but long decommissioned and now derelict Battersea Power Station on the south bank of the Thames opposite the Chelsea and Pimlico districts. Redevelopment of the site by the private developer Treasury Holdings UK, for owner of the site, listed company Real Estate Opportunities, is working with Transport for London (TfL) and London Underground Ltd (LUL) to promote the underground extension and gain the necessary government permission to build the proposed 3km long extension and its two new underground stations.

As well as vital to the £4 billion Battersea redevelopment, the extension will contribute to regeneration of the Wandsworth area south of the Thames and the second station on the route will provide Underground services to the new American Embassy being planned at Nine Elms. The current building, built in the 1960s in Grosvenor Square in the exclusive Mayfair district north of the Thames, requires significant modernization. A new building a Nine Elms, close also to the Vauxhall Station on the Underground Victoria Line and on the Waterloo mainline railway, will be built with the extra security, capacity and services required by the Embassy.

Extension on the Underground map

The UK division of consultant Parsons Brinckerhoff (PB) has taken the new extension through the planning and feasibility stages. "There are three route options for the line," explained Mike Francis, Senior Delivery Manager for PB UK. "The preferred route comprises 2.6km of twin TBM-excavated running tunnels and two mined underground stations at Nine Elms and Battersea. A second option takes a direct line to Battersea with no second station and the third takes a longer route that connects with the existing Vauxhall Station, bypassing a new station at Nine Elms. En route the new line will pass under the surface approach tracks to Waterloo Station, under the Victoria Line and Northern Line Underground running tunnels, a few meters above the Thames Water Ring Main
tunnel, 1m above a cable tunnel and 2m below a deep sewer tunnel, ending at the new underground terminus at Battersea."

A further 1.6km extension of this spur westward to underground stations at Wandsworth and Clapham Junction, is being proposed. An Underground connection at Clapham Junction would be one of the busiest railway/Underground interchanges and would relieve congestion at the Waterloo and Victoria Station interchanges.

Route Length (m) Intermediate station Min horizontal radius (m) Approx. cost 1 2,803+3,037=5,840 - 320 £428 million 2 2,970+3,111=6,081   Nine Elms 300 £508 million 3 2,855+3,313=6,168 Vauxhall 250 £682 million
Three underground options studied for the new alignment

Despite the current economic crunch, the project is to be developed using private funding. Treasury Holdings is responsible for securing the capital to fund design-build procurement of an estimated £750 million to £1 billion extension. The base cost of civil construction for the preferred option of a 2.6km long extension and its two new underground station is estimated at about £500 million with the remainder spent on land acquisition for stations, engineering and management services and risk management strategies. The completed facility will be handed over to London Underground for operation of services and maintenance of the infrastructure. This is much the same model as used for development of the Docklands Light Rail system to Canary Wharf which now extends under the Thames to Woolwich and Lewisham in southeast London. With public funds under pressure and committed to other transport projects in the capital, including Crossrail and much-needed upgrade of existing Underground stations and infrastructure, various vehicles are being considered including the selling of council bonds, a scheme based on tax increment financing whereby the investment is paid back via increased business rates once the project is complete.

Preferred underground route

With the feasibility phase completed in December 2008, a letter from London Mayor Boris Johnson in the summer urged all involved to push ahead with development. This has zeroed in this week on anticipated announcement by Treasury Holdings and LUL representatives of a consultant, from a list of seven, to take the project through its Transport and Works Act Order (TWAO) application to secure central government approval to build the line. This phase is expected to take about a year with submission of documents for a TWAO application by a target date of October 2010.

Public sector support of the project is provided by London Underground with a team of about 30 LUL engineers and management staff seeing the project through the preliminary planning, feasibility, government approval, and reference design phases. Once TWAO approval is granted, a consultant will be engaged to develop a reference design ahead of design-build procurement. With an anticipated six-year construction phase the extension could be in service by 2016.

Site of the new Embassy

Planning application for mix-use residential, retail, commercial and leisure redevelopment of the 40-acre Battersea site has been registered by Wandsworth Borough Council for consideration in summer next year. Depending on that process, construction is anticipated to start in 2012 with the last phase of the development completed by 2020.

Wandsworth Borough Council is also considering planning applications for the new American Embassy in Nine Elms. If approved, construction could start in 2013 towards a move-in date in 2016.

References

Crossrail buoyed by EU capital injection - TunnelTalk, Aug 2009
Crossrail launches construction phase - TunnelTalk, Aug 2009

Battersea Powerstation Redevelopment
New US Embassy in Nine Elms
Crossrail: The Project

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