FINANCE
construction work is more than half way to completion . The heavy lifting has been the tunnelling element of the scheme and that is about 90 percent of the way through : the ticket halls are fully excavated with construction making good progress .
The mayor of London Boris Johnson has understandably taken a close interest in the progress of the engineering work . At the end of March he visited one of the eight great tunnel boring machines ( TBMs ) 42 metres below ground at Liverpool Street Crossrail station . Victoria , and her
TBM and operator sister machine Elizabeth , are being prepared for the 750 metre push to Farringdon , which will complete the mammoth tunnelling operation . “ These hardworking beasts have slowly but steadily been working their way across London underneath our feet ,” enthused Johnson . “ The last time I saw them they were at Canary Wharf , and now nearly six million tonnes of earth has been excavated and their work is almost complete .”
The custom made 1,000 tonne and 150 metre long machines are giant underground factories that are not just tunnelling , but removing the muck and creating a sealed concrete tunnel as they go . Each machine has a rotating cutter head at the front , and a series of trailers behind , housing all the mechanical and electrical equipment required for the excavation of material . Almost all of the excavated material is put to good use . Threequarters of it is being delivered by rail and ship to Wallasea Island in Essex to create a new nature reserve in partnership with the RSPB .
While tunnelling is the sexiest part of the engineering operation , thanks to its sheer scale and the drama when the machines break through into a
12 May 2015