Crossrail's giant tunnelling machines unveiled
2 January 2012 Last updated at 02:38 GMT
Engineers are getting ready to start tunnelling beneath London in what has become Europe's biggest construction project.
Crossrail will cost almost £15bn and by linking areas east and west of the capital, will increase the city's rail capacity by 10%.
The company has just unveiled the giant tunnelling machines which will start work in March, and has started production of the tunnel liners at a factory in west London.
Richard Lister went to see them.