The Brusio spiral viaduct is a single-track nine-arched stone spiral railway viaduct. A signature structure of the World Heritage-listed Bernina railway, it is located near Brusio, in the Canton of Graubünden, Switzerland, and was built to limit the railway's gradient at that location within its specified maximum of 7%. The Brusio spiral viaduct forms part of the Bernina Railway section between Brusio and Campascio. It is just south of Brusio, and approximately 54 kilometres (34 mi) from St. Moritz. The viaduct was opened on 1 July 1908, upon the opening of the Tirano–Poschiavo section of the Bernina Railway.
