The first tunnel boring machine for London’s Crossrail project is going through final testing and will soon be dismantled for transport to the Royal Oak portal near Paddington.
The earth pressure balance (EPB) TBM has been assembled in Herrenknecht’s yard at Schwanau in Germany for commissioning, while work on another five EPB and two mixshield machines continues at the factory.
Contractors working on the Crossrail scheme have all selected Herrenknecht to manufacture the TBMs needed for the work. “We set a minimum specification for the TBMs and gave the contractors a preferred list of supplied,” said Crossrail project manager for the western tunnels Andy Alder. “They all independently selected Herrenknecht though. The benefit for the overall project is that spare parts and service can be shared across the scheme and it has also helped bring down the lead time for delivery.”
Crossrail chief engineer Chris Dulake added, “We originally thought that we would have to order the TBMs ourselves due to the lead times that were initially quoted by manufacturers. The main bearing used in the TBMs is also used by tank gun turrets and offshore wind turbines, so with current conflicts and the level of demand for wind power some manufacturers had lead times of 18 to 24 months for these parts.”
Herrenknecht fortunately had stockpiles of the right bearings so has been able to fast track the Crossrail machines. “We received the initial order in April this year and the machine will be delivered next month. Normally it takes 12 months to build a TBM,” said Herrenknecht UK managing director Roy Slocombe.
The completed TBM will be dismantled over the next few weeks and shipped to Tilbury docks before the parts are transported to the Royal Oak site where the machine will be reassembled. Launch of the TBM is expected in March 2012.