After driving a total of 6.5 km each, both of the Amsteg tunnel boring machines must be maintained. During the coming weeks, extensive maintenance work will be carried out on the cutting heads of Gabi I and Gabi II. Tunnel boring machine Gabi II will resume driving in the west tunnel at the end of March 2005 and tunnel boring machine Gabi I in the east tunnel in mid-April 2005.
In the Amsteg section of the Gotthard Base Tunnel, the two tunnel boring machines have cut more than half of the 11.35 km stretch from Amsteg to Sedrun. On March 9, 2005, 6711 m of the east tunnel (59%) and 6469 m of the west tunnel (57%) had been driven. On their way towards Sedrun, the two gigantic boring machines were recently cutting through very hard granite. This caused correspondingly intense wear of the cutting heads which must therefore now be main-tained.
Since March 9, 2005, tunnel boring machine Gabi II has been undergoing maintenance in the west tunnel. This machine will resume driving at the end of March 2005. Shortly before Easter, driving in the east tunnel with tunnel boring machine Gabi I will be suspended. Maintenance of the east machine will take until mid-April 2005. Both of the Amsteg tunnel boring machines were already maintained in summer 2004 as well as over the change of year 2004/2005.