Of the total of 153.4 km of tunnels, shafts and passages forming the AlpTransit Gotthard project, at the end of July 52.338 km or 34.1% had been excavated. The four tunnel boring machines (TBMs) have so far cut a total of 16.076 km. The present holidays on the construction sites are being used for maintenance of the TBMs. Whilst driving at Amsteg and Sedrun is progressing well, the rates of advance on the Bodio and Faido sections confirm that the already announced delay of approximately one year relative to plan caused by fault zones cannot be made up. Now that construction has started at Erstfeld, The AlpTransit Gotthard Company expects the Gotthard Base Tunnel to become operational in 2015.
Gotthard Base Tunnel
In the Bodio section, the tunnel boring machine (TBM) in the west tunnel has cut 5117.14 metres and that in the east tunnel 4043.12 metres. These distances include constructionally relevant geological fault zones through which the TBMs had to cut in 2003 and the first half of 2004. In some places, the difficult conditions required additional securing measures which made it impossible to achieve the planned rates of advance. On the Bodio section, a delay relative to plan was already announced by The AlpTransit Gotthard Company in the summer of 2003. At that time, increasing rates of advance allowed the assumption that the delay could be at least partially made up. However, it has now become apparent that this will not be possible. Based on present knowledge, The AlpTransit Gotthard Company expects breakthrough at Faido in 2006, and not as originally planned in 2005. Operation of the Gotthard Base Tunnel will start in 2015.
To increase the rate of advance, improvements to the driving system of the TBM at Faido are planned. Modifications to the backup train of the tunnel boring machine for lining the tunnel base have already been completed so that up to 30 m of the base can now be concreted daily. Smaller improvements are now also being made as part of the regular maintenance work during the present holiday period on the construction sites. The next opportunity will be at the planned shutdown of the machines between Christmas and New Year.
At Biasca, work on the overground approach lines to the south portal of the Gotthard Base Tunnel is making good progress and keeping within the planned schedule and costs.
At Faido, construction work on the multifunction station has now passed completely beyond the fault zone to the south. To the north, the east tunnel has also left the fault zone, but the transitional zone to the gneiss of the Lukmanier is longer and subject to greater squeezing than was assumed. In the west tunnel, driving has reached the end of the fault zone where squeezing is extreme and extensive securing measures are now being implemented.
On the Sedrun section, driving is progressing well. The predicted faults preceding the northern end of the Tavetsch Intermediate Massif were excavated without constructional problems, and driving at the northern end of the Tavetsch Intermediate Massif itself has begun. So far, no squeezing rock conditions have been encountered.
Pleasing progress is being made with driving at Amsteg. The TBM in the west tunnel has now advanced by 3183.70 metres and that in the east tunnel by 3732.50 metres, thereby very quickly crossing the forecast constructionally unfavourable Intschi zone without major problems. The construction schedule foresaw an interruption in driving of four months to allow measures for stabilizing the rock conditions in the fault zone. This planned stoppage of the two tunnel boring machines was not required. At the beginning of July, the TBM in the west tunnel even achieved a new record daily advance rate for the Gotthard Base Tunnel of 40.1 metres.
On July 19, 2004, placement of a rock weighing more than four tonnes by the future north portal at Erstfeld marked the start of work on the last section of the Gotthard Base Tunnel. In a first phase, preparations are now being made for the installations site. The award of contracts for work on Lot 151 at Erstfeld is expected to take place in summer 2005. The contracts will be for the construction of two parallel single-track tunnels with a total length of 7.7 km and the underground branch-off for the future under-the-mountain route. The actual driving work is planned to start at the end of 2006.
Ceneri Base Tunnel
The public application for planning permission for the Ceneri Base Tunnel took place in April 2003. The required credit was approved by the Swiss Council of States in December 2003 and the National Council in June 2004. From June 15 to July 14, 2004, the project amendments for the Ceneri Base Tunnel were published, and at the end of the year planning permission will be requested for the amendments 'Tutto Sigirino' including the wild-animal passage at 'Dosso di Taverne' and the rail connection at Sigirino. Planning permission is expected to be granted in mid-2005, allowing preparatory work to begin in the second half of the same year. The main work is planned to start in 2006.