The Lötschberg rail tunnel, a rail line providing an accompanied combined transport link between northern Europe and Italy, is part of the vast transalpine programme known as AlpTransit. At 2,000 metres below the summit of the Lötschberg, the Ferden tunnel, a central 7.7-kilometrelong section, is remarkable due its enormous size. The works required the installation of a powerful air-conditioning and ventilation system to deal with the high temperatures of the rock, which exceeded 47°C near the tunnel face, and relative air humidity of up to 100%.