At the heart of the Elizabeth line route are 42km of new tunnels that stretch under central London connecting existing railways to the west out of Paddington and to the east out of Liverpool Street.
In November 2008, an agreement was finalised for a £230m funding package from BAA to ensure Crossrail will guarantee a fast train service four times an hour to/from Heathrow for the majority of the day.
In July 2008, the Department for Transport (DfT) made an Order to appoint Crossrail Ltd (CRL) the Nominated Undertaker for the Crossrail works. The Order, which transferred to CRL the powers to gain the necessary consents and build the railway, was made under the powers of the Crossrail Act which gained Royal Assent in July 2008. CRL now changed from a planning and promotional organisation to the Delivery Agent for the new railway.
Utility diversions for Crossrail construction commenced in October 2008 until early 2013 at Bond Street, Paddington, Liverpool Street and Tottenham Court Road areas. Small trenches, approximately 1.5m deep and 1m wide were dug at various station sites to enable Crossrail to identify whether below ground services - pipes, cables and so on - matched with information provided by utility companies and other service providers. This was essential to enable Crossrail's main construction works to proceed safely from 2010 with sufficient knowledge of the existing conditions.
In December 2008 an agreement worth up to £350m was finalised with the City of London Corporation, who agreed to make a direct contribution of £200m to the Crossrail project. In addition, the City of London Corporation would seek contributions from businesses of £150m and guaranteed £50m of these contributions.
Also, in December 2008, Canary Wharf Group agreed to contribute £150m towards the costs of the station at Canary Wharf and that work on the station would begin in 2009.
In March 2009, Crossrail announced the appointment of Transcend, a joint venture between AECOM, CH2M Hill and Nichols Group, as its Programme Partner. The Programme Partner would provide strategic programme management with the object of helping Crossrail to deliver safely the overall programme to time, to the desired standard and within budget.
In April 2009, the DfT confirmed that it had appointed Jacobs Engineering UK Ltd as the Project Representative for Crossrail. The Project Representative would provide oversight support to the project sponsors (DfT and TfL) to ensure that Crossrail would deliver the project on schedule, within budget and to the agreed standard.
On the 15 May 2009, Crossrail reached a landmark moment as the then Mayor of London, Boris Johnson and the then Rail Minister Lord Adonis marked the start of construction for Crossrail. The formal start of construction, held at Canary Wharf, signalled the intensification of work on Crossrail and followed the confirmation of major funding agreements with BAA, Canary Wharf Group and the Corporation of London, the appointments of the Chief Executive and Chairman of Crossrail and the appointment of contractors who would oversee the overall project delivery including design, tunnelling and construction.
Canary Wharf Group subsidiary Canary Wharf Contractors (CWC) was the lead contractor for the design and construction of the Canary Wharf station. CWC handed over the station to Crossrail in 2015 for final fit-out and testing & commissioning.
In August 2009, Crossrail published notices in the Official Journal of the European Union (OJEU) inviting expressions of interest for three principal tunnelling contracts –Tunnels West, Tunnels East and Thames Tunnel. The publication of these OJEU notices marked the beginning of the procurement process for the construction of the new rail tunnels in central London. In December 2010 the contracts for the Western Running Tunnels (Royal Oak to Farringdon) were awarded to BAM Nuttall, Ferrovial Agroman and Kier Joint Venture and the Eastern Running Tunnels (Limmo to Farringdon, Limmo to Victoria Dock and Stepney Green to Pudding Mill Lane) to Dragados and John Sisk Joint Venture. The contract for the Thames Tunnel (Plumstead to North Woolwich) was awarded in April 2011 to Hochtief Construction and J Murphy & Sons Joint Venture along with the refurbishment of the Connaught Tunnel to Vinci Construction.
All 8 tunnel boring machines for Crossrail were manufactured by Herrenknecht in Germany.
From 2011 to 2013 a total of seven contracts were awarded for the new central section stations, including:
- Paddington station awarded to Costain Skanska Joint Venture (July 2011),
- Farringdon station awarded to BAM Nuttall, Ferrovial Agroman (UK) & Kier Construction Joint Venture (November 2011);
- Whitechapel station awarded to Balfour Beatty Civil Engineering, Morgan Sindall & Vinci Construction UK Joint Venture (November 2011);
- Liverpool Street station awarded to Laing O’Rourke Construction Ltd. (March 2012);
- Tottenham Court Road station awarded to Laing O’Rourke Construction Ltd. (June 2012);
- Custom House station awarded to Laing O’Rourke Construction Ltd. (August 2012);
- Bond Street station awarded to Costain Skanska Joint Venture (February 2013);
Following Network Rail’s award of the contract for Abbey Wood station to its principle contractor, Balfour Beatty, work started in 2013 and included the construction of an interim station, the demolition of the old station and the installation of a new one-mile section of track. Works to redevelop the station were completed at the end of 2017.
Final fit-out, testing and commissioning remains ongoing across eight central section stations: Paddington, Bond Street, Tottenham Court Road, Farringdon, Liverpool Street, Whitechapel, Canary Wharf and Woolwich.
Custom House was completed and handed over to TfL in May 2020. The main structure of the new station assembled in a year and a day was completed on 25 March 201. It used 825 components manufactured near Sheffield, transported to London and assembled on site, saving time and reducing disruption.
The redevelopment works at Tottenham Court Road Tube station, started in early 2010 and completed in 2016, delivered an enlarged ticket hall nearly six times the size of the current one; new station entrances and additional access points to the Northern and Central line platforms to reduce congestion; and additional escalators and five new lifts to provide step-free access. TfL awarded the contract for the redevelopment of Tottenham Court Road Tube station to Taylor Woodrow Construction and BAM Nuttall Limited in 2009.
In addition to the new tunnels and stations the central section of the Elizabeth line includes a number of shafts and portals, which house railway systems and mechanical equipment to support Elizabeth line services. The designs for the shafts and portals are bespoke to integrate with new and existing infrastructure.
There are five tunnel portals that make up the Elizabeth line’s central section: Royal Oak, Pudding Mill Lane, Victoria Dock, North Woolwich and Plumstead along with the Connaught Tunnel in the Royal Docks which dates back to 1878. The portals provide an entrance and exit for trains to the underground sections of the Elizabeth line.
Construction of Royal Oak Portal, the first of the five new tunnel portals to be built for Crossrail, commenced in January 2010 and was completed in September 2011. These portal structures were also the entry or exit point for the TBMs used to construct the new twin-bore tunnels.
There are five shafts: Fisher Street, Eleanor Street, Mile End, Stepney Green and Limmo. These structures along the tunnels house drainage ventilation fans and emergency access and egress if required. Main construction of the shafts started in 2010.
The locations of the shafts along the route were selected based on the need for air flow and access to the tunnel and on land availability on the surface. All shafts and portals have been tested and commissioned and are now in the final stages of the assurance and handover process and this is scheduled to be completed in Autumn 2020.
The twin-bore running tunnels, one each for eastbound and westbound services, begin in the west at Royal Oak portal near Paddington. They link the central London stations before splitting into two eastern routes at an underground junction below Stepney Green. The south eastern section surfaces at Victoria Dock portal, serves the new surface station at Custom House and then passes through an existing tunnel, the Connaught Tunnel, under the Royal Docks. The route then enters a new tunnel to pass under the Thames and through the new underground Woolwich station before surfacing at Plumstead and continuing along new tracks built adjacent to the existing North Kent Line to reach a terminus at Abbey Wood station. The north eastern route comes to the surface at Pudding Mill Lane, where the Docklands Light Railway station needed to be relocated to accommodate it, and then joins the Great Eastern Main Line to serve existing stations from Stratford to Shenfield.
The precise route of the tunnels was chosen after extensive studies and surveys to consider the potential impact on many thousands of buildings above the route, including many listed buildings. The route had to weave around foundations, existing Tube lines, sewers, utilities and other underground infrastructure. At Tottenham Court Road, one of London’s most congested underground locations, the route had to be built within a metre of an operational Northern line platform tunnel.
Crossrail tunnelling began in May 2012 at Royal Oak portal with tunnelling machine Phyllis and ended at Farringdon in May 2015 with the arrival of tunnelling machine Victoria from the east. For three years, the eight 1,000 tonne tunnelling machines bored 42km of new 6.2m diameter rail tunnels under London.
For further information on tunnelling during the Crossrail project, please visit our Tunnelling section of the website.
What happened to each of the TBMs?
- Phyllis and Ada were driven ‘off-line’ after arriving at Farringdon, the front ‘cans’ and cutterheads left buried 30 metres below ground. The 130-metre long trailer systems were removed via the Fisher Street shaft and returned to the manufacturer, Herrenknecht, for recycling and reuse.
- Victoria and Elizabeth were driven into the eastern end of Farringdon station, where platform enlargements had been constructed, and were then stripped and dismantled underground. Their 130-metre long trailer systems were removed via the shaft at Stepney Green and returned to the manufacturer for recycling and reuse. The cutter heads were cut into small pieces and removed via the shaft at Farringdon. The front ‘cans’ of each machine were left in the tunnels and Elizabeth line trains will pass through them when services begin.
- Mary, Sophia, Jessica and Ellie were also dismantled with parts returned to the manufacturer to be recycled for use on future tunnelling projects.
Crossrail’s eight tunnelling machines excavated a total of 3.4 million tonnes of material. A total of 7 million tonnes of material was excavated during the construction of Crossrail, 98% of all excavated material was re-used.
In a landmark partnership with the Royal Society for the Protection of Birds (RSPB), 3 million tonnes of material excavated from deep below the capital was used to create a flagship wetland nature reserve twice the size the City of London at Wallasea Island in Essex.
Material from Crossrail’s western tunnels was transported by rail from Westbourne Park to Northfleet in Kent before being shipped to Wallasea. As many as five rail movements took place between Westbourne Park (western tunnels) and the Northfleet transfer site per day at peak. Material from Crossrail’s eastern tunnels was shipped direct to Wallasea from Instone Wharf near Canning Town.
Five ships were dedicated to transport of Crossrail excavated material to Wallasea Island. 1,528 shipments delivered 3 million tonnes of excavated material and the last shipment of excavated material donated by Crossrail arrived in Essex in April 2015.
For further information on sustainability and the environment n the Crossrail project, please visit our Environmental Sustainability section of the website.
Over 200,000 concrete segments were required to line the 42 kilometres of running tunnels. Seven segments and a keystone were used to make up every tunnel ring, locked together to build a concrete tube. Each segment weighed 3,000 kilogrammes and each keystone weigh 1,000 kilogrammes. Three factories manufactured the pre-cast concrete segments and keystones:
- For the Western tunnels, a factory established in Old Oak Common, west London produced 75,000 tunnel segments and employed 60 people at its peak,
- For the Eastern tunnels, a factory in Chatham, Kent, produced 110,000 tunnel segments and employed 120 people at its peak, and
- For the Thames tunnel, a factory in Mullingar, Ireland produced 25,000 tunnel segments.
Keeping the machines supplied with materials was critical to maintaining production and was done via a temporary construction railway, laid beneath the machines to move people and materials to and from the cutterhead. The construction trains were relatively small and carried heavy loads on narrow guage track, directly bolted to the tunnel floor but provided with noise attenuation where necessary to mitigate noise and vibration.
Restoration of Connaught Tunnel by filling with concrete foam and reboring, as originally intended, was deemed too great a risk to the structural integrity of the tunnel, and so work was required to deepen, strengthen and widen the structure. 13 million litres of water were drained from the dock that runs above the tunnel to allow Crossrail workers to access the structure from above. The rail tunnel originally served the Royal Docks when they formed the largest enclosed docks in the world, serving large ships from all over the globe. It survived a hit from a bomb during WW2 and is the only existing tunnel re-used for Crossrail. This work took place during 2013.
Prior to the above ground station construction starting, 14km of station and platform tunnels, passenger walkways and other spaces were created through a mining technique known as sprayed concrete lining.
In May 2012, the project’s first two sprayed concrete tunnels were constructed under Finsbury Circus in the City of London. The two tunnels were temporary structures and were used for compensation grouting, one of the ways that Crossrail could control any ground movements that could result from tunnelling activity. By July 2012, the construction of Crossrail’s first permanent sprayed concrete lined tunnels on the project was underway at Blomfield Street for Liverpool Street station.
The sprayed concrete lining method has been used extensively on Crossrail to form each of the station platform tunnels at Bond Street, Tottenham Court Road, Farringdon, Liverpool Street and Whitechapel, cross-passages between the platform tunnels, ventilation tunnels, concourse tunnels, cross-over caverns and ventilation, escape and intervention shafts across the central section of the route.
In October 2013, Crossrail announced that it had awarded the contract for Paddington New Yard to Costain Limited. Paddington New Yard, located between the Westbourne Park Tube station and Paddington National Rail station, contains both the Royal Oak portal and Westbourne Park Crossrail worksites. The contract included the construction of a new 180 metre long elevated bus deck to connect to Westbourne Park Bus Garage, the relocation of an existing concrete batching plant, and preparatory works for the installation of new rail track and associated systems for Crossrail. Prior to Crossrail, Paddington New Yard was used for the maintenance and overnight stabling of buses. Under the Crossrail Act, Crossrail Limited was required to provide a replacement facility at Paddington New Yard.
Crossrail Ltd demanded the highest standards of health and safety across the project and we continue to work closely with our principal contractors in support of making sure this is the case. Since construction work begun on the project in 2009, there has sadly been on construction fatality. This incident took place on 7 March 2014 at the site in Fisher Street. There have also been four fatal collisions involving HGVs or lorries working for sub-contractors on the Crossrail project - three cyclists and one pedestrian - the last occurred on 19 February 2015.