Guadarrama Tunnels are 50% CompleteThe four TBMs have bored half of the twin tunnels under Sierra de Guadarrama on the high speed line from Madrid to Valladolid via Segovia. At end-January 2004, there was still 30,501 metres to go to complete the two tubes from four drives. A total of 26,703 m has already been excavated. Building of the cross passages between each tunnel has also commenced for emergency escape, access and service. Each is 25 m in length. To date, seven have been dug at intervals of one kilometre. When the tunnels are commissioned, there will be one at 250 m intervals.Progress of the southbound TBMs which started on the Segovia side is slightly higher, although the daily advance is virtually identical at 16-20 linear metres per day on each of the four drives. The machines have already excavated 8,500 m and 7,500 m on the two southbound drives while 6,600 m has been excavated on the drives which started from the Madrid side. The best day achieved 64 m (excavated and lined) and the best month 980 m. The four double-shield TBMs, two Herrenknecht and two Wirth, are drilling two 28.37 km tunnels under Sierra de Guadarrama. As they progress, the machines open a 9.5 m-diameter tunnel which is immediately lined with seven 1.6 m-wide concrete segments. The inner diameter is 8.5 m.The investment in the tunnels will cost EUR1,162 million, which is the the biggest share of the total budget of EUR1,861 million for the Madrid-Segovia-Valladolid high speed line. Tunnelling is expected to be finished in one or one and a half year although the TBMs will have to deal with two big faults, approximately in the middle of the alignment, which will take more time. Click es/16. Visit www.herrenknecht.com and www.wirth-europe.com 11/04.