It was picked as TBM supplier for six of the eight TBMs needed on the project earlier this year, and has now secured the deal for the final two that will drive a tunnel under the Thames in southeast London.
To construct the 21km of twin-bored tunnel required for Crossrail, eight TBMs will be required. They will undertake 10 individual tunnel drives to construct the 6m diameter rail tunnels. The first two TBMs will launch from Royal Oak in spring 2012.
Construction of the Thames Tunnel is being undertaken by a joint venture of Hochtief Construction and J Murphy & Sons, and it was they who selected the German company to construct the remaining two TBMs.
To avoid any Bombardier-type controversy, Crossrail managers were swift to point out that there are no UK-based TBM manufacturers.
Slurry TBMs will be used to construct the 2.6km twin bore Thames Tunnel due to the chalk ground conditions in this part of the capital. The remainder of the tunnels, between Royal Oak, Pudding Mill Lane and Victoria Dock Portal will be constructed using earth pressure balance machines that will pass through ground which is predominantly London clay, sand and gravels.
The slurry TBMs will be launched from Plumstead Portal in late 2012 and will tunnel westwards towards North Woolwich. Construction of Plumstead Portal is now underway, with work for North Woolwich Portal starting in early 2012.
Factory assembly of the first two TBMs begins in October and will complete during November, ready for testing. The first TBM components will begin arriving in the UK at Tilbury Docks in December with the second TBM arriving later in January. The TBM components will be transported to Westbourne Park for re-assembly.
Herrenknecht will also deliver two TBMs to Limmo Peninsula for the eastern running tunnels in mid 2012, two machines to Stepney Green and two machines to Plumstead later in 2012. The TBMs required for Crossrail will be up to 120m long and weigh around 850 tonnes.
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