Tunnel construction got underway on two tunnels for the Bothnia rail line in Sweden at the beginning of last month.
The first is the 2.1km long Varvsberget tunnel. The US$23.8M project, constructed by Skanska, includes a 1.2km long service tunnel and a central access tunnel. Engineers will tunnel in both directions simultaneously from the central access tunnel. It should be complete by June 2005.
The second is the US$27.7M, 3.3km long Åskottberget tunnel, which also includes the construction of a 2.3km long service and emergency tunnel. Constructed by the Swedish firm Oden Anläggning, it should be completed by the end of 2005.
The winning bids for the two longer tunnels on the project – the Namntallhöjden tunnel (6km), and the Björnböleshöjden tunnel (5.2km), both with parallel 25m2 service tunnels – will be announced in November this year.
The US$1.2bn, 190km long Bothnia high-speed rail link is all single track, with passing stations every 10km-14km, determining the cross section on all 15 tunnels on the project to be 70m2.
There are 25km of tunnels on the Bothnia line, accounting for 20% of the project’s budget. The geology for the alignment is good-quality gneiss (see T&TI, October 2002, for project details).
