The Interregio 2032 VORALPEN EXPRESS of the Südostbahn, with a "Traverso" RABe 526 and a "Flirt" RABe 526.0, is crossing the 99 meter high Sitter viaduct between St.Gallen Haggen and Herisau (Gübsensee crossing station), highest railway bridge of Switzerland. The Sitter viaduct has a main span of 120 meter, a length of 365 meter and was built between 1908 and 1910 for the Bodensee-Toggenburg-Bahn (BT) from Romanshorn via St.Gallen-Herisau-Wattwil to Nesslau. The trussed girder has a weight of 920 metric ton. Down in the gorge the Kubel hydro power station of 1900, very first storage power plant of Switzerland, using the nearby Gübsensee for water storage.
