WORK started on the high speed rail link a year ago and the most visible evidence can be seen close to J510 on the A-7 at La Herreria. The railway will burrow under the CabreraMountains to resurface in the Cabo de Gata. Some may have wondered why there is a huge white roller coaster pointing towards the sky. Two parallel tunnels each 7630 metres long that are about to be bored. The two tunnels will be 26M apart and will have 19 connecting tunnels dug every 400M for maintenance and emergency use.
The largest tunnel boring machine in the world or TBM is the German built.
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S-373Herrenknechtdouble shield and it is owned by the Spanish Govt. It was dismantled from its last project in the Asturias and 500 trucks transported it to Sorbas for reassembly and now it’s ready to start work. The TBM is a mile long and it is AWESOME. The TBM currently holds the world speed record for tunnelling as it managed up to tunnel up to 105M a day on the Madrid to Valencia AVE line in 2007/8.
The reason for the TBM’s great length is because it is in effect many different machines all working together to create the tunnel. At the front is the cutter which revolves at very high speeds to create a ring 9.63m wide. The machine then has heavy plates to secure the remaining rock fast whilst the impressive sounding lining segment erector installs a circular reinforced concrete ring inside the circumference of the tunnel every 1.6M. Seven segments weighing up to nearly nine tonnes each fit together to make a watertight seal about 50cm thick. Other sections remove the rock to the rear of the machine by conveyor belt hence the white roller coaster.
Two factories have been specially constructed each end of the tunnel to build the concrete rings and they work around the clock as up to 60 complete circular sections may be needed each day to feed the hungry machine. The other factory can easily be seen at the Carboneras junction 494 on the A-7. A huge electricity sub-station needed to be built at La Herreria to power the TBM.
I was privileged to attend the opening ceremony on behalf of the Euro Weekly News where Govt. Ministers and local dignitaries spoke about the huge social and economic benefits the 185km line will bring to Andalucía. As well as passengers freight will be carried from the Port of Almeria throughout Europe. With a station planned for Vera – Almanzora we can all benefit locally as well.