The first of ten giant tunnel boring machines has been unveiled by Crossrail and the countdown is now with less than one hundred days to go before tunnelling begins on the largest construction project in Europe: Crossrail.
The first of the Crossrail tunnel boring machines is now fully assembled and is currently undergoing rigorous factory testing before it is dismantled and shipped over to London. The massive Crossrail tunnel boring machines have been built by the German company, Herrenknecht AG in Germany, the same company who were also responsible for supplying tunnel boring machines for the Jubilee Line Extension and the Docklands Light Railway Extension.
Crossrail tunnelling work is scheduled to begin in March next year and the first TBM will be sent underground at the Royal Oak Crossrail portal. A second tunnel boring machine will be launched from Royal Oak portal a few weeks later. The next TBM launch will take place at Limmo Peninsula towards the end of next year. Further launches are scheduled for 2013 and 2014.
In order to complete the tunnelling part of Crossrail construction, a further seven tunnel boring machines will be required. In total, there are ten tunnel drives planned at various points on the Crossrail route and by the time the tunnel boring machines have completed their work, a total of 21 kilometres of tunnel will have been bored beneath the city of London.
Each tunnel will be 6.2 metres in diameter and as the TBMs progress down the tunnels, pre-cast concrete reinforcement rings will be put in place to strengthen the tunnels. In order to maintain a ready supply of pre-cast concrete rings, a concrete segment factory has been constructed at Old Oak Common. This will supply concrete for the western running tunnels between Farringdon and Royal Oak.