Two Other TBMs Start in PajaresIn mid-September 2005 the second of the five TBMs started its job at the Pajares tunnels, which form part of the Leon-Asturias high speed line. This is a NFM Technologies single shield TBM for hard rock (Wirth Group) used in open mode, that will perforate the east tube on contract 1 between La Pola de Gordon and Folledo in Leon province, parallel to the west tube, where another TBM started last 13th July. The length of the TBM is 170 m with the back-up and its weight is 1,950 tons. Its diameter is 9.93 m. The installed total power is 8,100 kVA (14 x 350 kW). The nominal thrust is 144,000 kN. The machine is equipped with 26 hydraulic cylinders. The nominal torque of the cutterhead is 21,000 kNm and its rotation speed is 0-6 rpm. To date, the machine has installed 60 rings and excavated 96 metres. Click here. Visit www.nfm-technologies.comOn 22nd September, another TBM also started working on contract 2 Folledo-Viadangos to drive a 5.5 km access tunnel from the municipality of Buiza, near Folledo (Leon province), up to the connecting point with the main tunnels (2 x 4.5 km). A Herrenknecht double shield hard rock TBM is used, 12 m in length (without the back-up) for a weight of 1,500 tons. The diameter of the cutting head is 10.16 m and the inner diameter of the tunnel will be 8.5 m. The total power of the main drive is 5,600 kW at the cutterhead. The total installed power is 8,000 kVA. The maximum thrust is 104,050 kN. The cutterhead is equipped with 56 disc cutters and four doubles. Visit www.herrenknecht.comContract 2 is the central section of the Pajares tunnel project. It was initially planned in the original project for contract 2 that two 600 m-deep shafts would be sunk to access to the central section of the tunnel, but the contractors - Dragados and Obras Subterraneas - proposed to ADIF, the client, changes to the project consisting in replacing both shafts by an access tunnel of about 5.5 km up to the start point of the contract. Once this access tunnel is excavated, the TBM will pursue its task with the 4.5 km corresponding to the west bore. At the end of the main tunnel (junction with contract 4 Viadangos-Telledo), the machine will be dismantled and transported back to the start point (junction with contract 1) where a cavern will have been built to permit its placement inside to commence the second, east bore and drive another 4.5 km up to the junction with contract 3 Viadangos-Telledo (east tunnel). The segment factory for this contract, situated in the village of La Robla in Leon province, had already produced 850 lining rings when the TBM started. This second contract also includes a stop area, preferably 400 m in length. The time frame for construction is 60 months and the budget totals EUR401 million. Although tunnelling has still to commence from the Asturian side (north) to perforate the Pajares pass through which the trains will travel, preparatory works in the Telledo area have begun many months ago with massive earthworks required for the tunnel portal and, above all, to provide access to the place. It is not possible to transfer huge quantities of heavy machinery on the existing narrow road that arrives there from Campomanes. Therefore, work is underway to cut through hills to avoid curves, road are widened and enormous volumes of material are displaced to build a new road access that will permit the passage of heavy machinery. A look at the steep Asturian topography suffices to explain the timing difference between the start of works on the Leon side (south) and the Asturian side. In Pola de Gordon (Leon side in the south), the tunnel portal is at close range from the road and can be seen from there. In addition, the place is a large flat area where the worksite offices, the segment factories and other facilities are all grouped together. On the contrary, on the Asturian side of the project, the landscape is very different: steep mountains and deep valleys that complicate the preparations. These topographic complications to work in Asturian territory have already been predicted and are not a surprise. Therefore, the date for the conclusion of the Pajares tunnel project and the arrival of the high speed trains to Asturias are still scheduled for 2009. The first TBM that will work on the Asturian side should arrive in mid-November. By then, it is foreseen that the accesses will be finished and all associated works (like the segment plants) will be operational. The other TBM that will drive the other tunnel, parallel to the first, is expected to arrive in early 2006. Excavation will not begin immediately because, as was the case on the Leon side of the tunnels, the massive TBMs will arrive in parts that will have to be reassembled. Then tests will be carried out, and it is not before a few months that tunnelling will actually commence. Click es/55. Visit www.adif.es 41/05.