An exciting proposal for London’s regeneration

Cross London Rail Links’ proposals for a major new railway for London and the south of the UK, with benefits for the whole of the country, continue to move steadily through the parliamentary process towards construction.

Proposed in 1999 as part of a central London rail study (following a prior abortive attempt at legislating for a similar scheme in the early 1990s), work began in 2001 to design a new network which will link Maidenhead and Heathrow airport to the west of London, with the counties of Essex and Kent in the east through new tunnels running under central London. The project represents one of the largest transport engineering initiatives in the UK’s recent history.

Known as ‘Crossrail’, the project is a 50/50 joint venture between Transport for London (TfL) and the Government’s Department for Transport (DfT). Its objectives are: to support the continuing development of London as a World City and a global financial centre; to support London’s economic growth and its regeneration areas by boosting capacity and reducing congestion on the existing transport network; and to improve rail access into and within London.

Following several major public consultations between 2002 and 2005, the Crossrail Bill was introduced in Parliament in February 2005. It has been intensively studied by the Crossrail Select Committee in the Lower House over the past 18 months, and has attracted some 466 petitions, each of which has been addressed. The same process will follow shortly in the Upper House. Thereafter enactment of the Bill, and Royal Assent, will in turn provide the legal approval needed to build the railway. Discussions are also on-going with the Treasury, and other key stakeholders, to finalise a funding mechanism with the possibility of an announcement later in 2007.

Subject to Assent and funding being given, and following a procurement process, construction work could commence, with the first trains running on the new network from 2015. The key benefits of the railway will be:

• Future capability – The transport capability to cope with London’s forecast population and economic growth
• Capacity/decongestion – Increased rail capacity into and across London will mean the potential for more passenger journeys per day, reducing congestion and crowding on the London Underground and regional rail network (for example, a 36% reduction in congestion at Liverpool Street is expected with Crossrail). It will also reduce road congestion as more people will be encouraged to use the train, due to shorter journey times
• Accessibility – New journey possibilities, with improved access into and across London, reductions in journey times and more efficient use of transport resources through the development of strategic interchanges
• Business – Crossrail will support sustainability for London’s role as Europe’s financial and business centre. Up to one third of the UK’s GDP is generated in London and the South area
• International links – New strategic interchanges delivered through Crossrail will improve London’s international links and the quality of its visitor experience – through faster journey times, reduced crowding and easier travel. This includes the Channel Tunnel Rail Link at Stratford – Heathrow, Gatwick and London City airports, Stansted airport from Liverpool Street and Luton airport from Farringdon via Thameslink
• Regeneration – Crossrail will deliver regeneration of priority areas, including the Isle of Dogs, the Royal Docks, Stratford, the City Fringe and Hayes/Southall, supporting an estimated 80,000 jobs in these areas. Approximately 9,000 people in these areas – who might otherwise find it more difficult to find employment – will have a better opportunity to get work as a result of improved accessibility via Crossrail

According to the project team’s calculations, the scheme overall has the potential to support £19 billion of growth with a cost:benefit ratio of 2.6:1 with at least £30 billion of wider benefits over 60 years to the UK economy. This signals a very effective return against the capital investment required to build the new railway. Crossrail also has a key part to play in the regeneration of areas along the route, as well as strategic regeneration areas like the Thames Gateway, and the delivery of much needed new homes in this part of the country. Alongside this physical transformation, Crossrail will also deliver employment benefits, both in terms of creating new opportunities during construction and improving access for existing employees and businesses. It will link and boost the three financial and business centres of the West End, the City and Canary Wharf.

In addition, 14,000 construction jobs are being created by the railway, over the life of the project. Cross London Rail Links is currently exploring programmes with Transport for London (TfL) to ensure localised labour is resourced as far as possible.

The construction of the Crossrail network generates significant engineering challenges. The proposed route requires 22.5km of twin-bore tunnelling, such that up to six tunnel boring machines (TBMs) could be working at the same time on different branches of the new network.

The new tunnels will cross the centre of London from west to east, from Paddington through to Pudding Mill Lane (near Stratford in the London Borough of Newham) and down to a new station in Docklands serving the Canary Wharf area. The Crossrail route alignment crosses beneath the River Thames in a tunnel via Woolwich to eventually terminate at Abbey Wood, serving the Kent area.

All of the tunnels have an internal diameter of approximately 6m. The tunnels in the central area (between Paddington and the East End) will utilise Earth Pressure Balance (EPB) TBMs while the tunnels underneath the River Thames may use slurry type TBMs. Geotechnical investigation continues to be carried out along the route in preparation.
EPB and Slurry TBMs have an excellent record of driving tunnels in relatively soft, mixed ground conditions for controlling ground movements and maintaining outstanding rates of tunnel production.

The general ground conditions across the route can be summarised as:

• Stratum
• Made Ground
• Terrace Gravel
• London Clay
• Lambeth Group
• Thanet Sands
• Upper Chalk

The running tunnels will be lined with precast concrete segments. The precast concrete segments will utilise technologies for recent UK tunnelling projects (e.g. Channel Tunnel Rail Link, London Underground Heathrow Terminal 5 extension). Steel fibre will be used to reinforce the segments, and monofilament polypropylene fibre used to provide fire resistance.

On the proposed line, trains will be almost twice as long as a current London Underground Tube train, at up to twelve cars and 240 metres (787 feet), necessitating platform lengthening at some existing surface stations to be used as part of the new route.

In addition, seven new underground stations will be built in the centre of London, and several other surface stations will be rebuilt – at Ealing Broadway, Southall, Ilford, Romford and Custom House. It is anticipated that 10-car trains will be run at the start of operations but all new stations will be constructed and fitted out to allow 12-car trains to run if called for in the future.

The main depot will be based at an existing rail depot in North West London, and the control centre at Ilford depot, utilising and building an existing rail plant. Stabling will be created along the route.

The new central London stations will be below ground, with platforms at depths up to about 35m below street level and around 245m in length. All stations will have ventilation and emergency escape shafts at each end of the platforms.

The platforms will be constructed either in tunnels about 13m wide and 11m high or in deep boxes constructed from the surface.

Station tunnels will be constructed from sites (normally a ticket hall site) at the stations, independent from the running tunnels (running TBMs are “dragged” through the completed station platform tunnels).

Tunnelled stations will generally be lined using spray concrete techniques. This method has the advantage that an egg shaped tunnel section can be used to accommodate trains and platform (minimising the amount of excavation) and it is simpler to form openings in the tunnel for cross-passages, ventilation etc. Box stations will be constructed top down, again before the running tunnels are bored.

The Crossrail fleet will comprise modern, energy-efficient, high performance trains. Each train will be able to carry up to 1,500 seated and standing passengers, approximately double that of a Central line tube train.

Their performance will be capable of delivering a train approximately every two and a half minutes (during peak times) in the central area – 24 trains an hour in each direction. Each carriage’s design will facilitate rapid entry and exit with three sets of wide double doors on each side, although the design has yet to be finalised. Interiors will be climate controlled.

Most Crossrail stations will have two ticket halls, one at each end, creating, effectively, two stations with a greater reach of customers for one set of platforms. For example, at the Liverpool Street station stop, passengers will also be able to alight at Moorgate station, up to 10 minutes walk away on the surface.

Wherever possible, these ticket halls will link to existing London Underground infrastructure and all the new Crossrail stations will have step free access for people with reduced mobility.

Crossrail also proposes to provide platform edge doors (PEDS) at all new subsurface stations providing further safety benefits and increased reliability of services. PEDS will improve the passenger environment on the platform by reducing the air turbulence effects from train movements. Stepfree access from surface to carriage will be a priority for all new stations and most surface stations.

In 2006, Crossrail awarded multi-disciplinary design contracts for development work in a major step forward in the co-ordinated plan to deliver the project on time and to budget. The appointed consultants are working with CLRL to prepare an affordable design for the project, which will form the basis for construction once the Crossrail Bill has received Royal Assent and become an Act of Parliament.

The consultants have joined Crossrail’s existing development team, which is led by Bechtel and is co-located at Crossrail’s offices in Victoria. It comprises Bechtel as Development Manager plus Mott MacDonald, Halcrow, and Arup/Atkins. In addition Scott Wilson is designing the surface works and Taylor Woodrow is Enabling Works Managing Agent.

Crossrail is a major European infrastructure project which will use the resources of the world wide construction industry. It will help to sustain London’s role as the world’s leading financial capital and strengthen London’s links with the UK’s transport system and beyond.

About the author

Douglas Oakervee is the Executive Chairman of Cross London Rail Links Limited. Mr. Oakervee is one of the country’s most distinguished civil engineers, with vast international experience in the successful delivery of major projects. Formerly, he oversaw the construction of the new Hong Kong airport, and was elected as the 139th President of the Institution of Civil Engineers in 2003.

He is also currently the chairman for Engineers Against Poverty and through the Institution of Civil Engineers has helped facilitate better relationships between the Government and Industry in various aspects of engineering.