Viaduc de Grandfey
The Grandfey railway is on the railway line from Bern to Fribourg and is one of the largest bridges in Switzerland.
The following information is condensed from the Wikipedia entry.
First Viaduct
Built between 1857 and 1862 .
Planning for the construction process was carried out by Ferdinand Mathieu, senior engineer of the French iron and steel company Schneider et Cie in Le Creusot, which had received the metalworking contract for the bridge. The earthwork and masonry work was carried out by the Swiss company Wirth, Studer & Co.
The masonry stone bases were up to 32 m high. The pillars consisted of 3.93 m long cast iron pipes, which were arranged on 11 piers 43.20 m high, supporting lattice wrought iron trusses. It is regarded as the first bridge where Ferdinand Mathieu, senior engineer of Schneider & Cie., used the incremental launch method that he invented. In this case, the lattice girder beam that was pushed over the valley served as a crane for the construction of the first and subsequently the next pillar.
The Grandfey viaduct influenced the Busseau Viaduct in France, which was designed shortly afterwards by Wilhelm Nördlinger. It also served as a model for the Malleco Viaduct in Chile, which was also built by Schneider et Cie. from 1886 to 1890.
Second Viaduct
With the electrification of the Swiss Federal Railways network, the bridge had to be strengthened. The Grandfey Viaduct was rebuilt in a between 1925 and 1927. Supported by pillars consisting of iron trusses completely encased in concrete, the bridge has six wide concrete arches that are built according to the Melan system, over the top of which runs a pedestrian walkway. The five middle arches have clear spans of 42 m.