The great railway viaduct was built between 1884 and 1886 by the company Visconi and Caligari. Oreste Mugnani, an engineer of the Genio civile from Florence, planned it.
The Viaduct crosses Pettenasco on the Novara-Domodossola line;it bends at a height of 32 metersit and it consists of eight arcades,each of them being 16 meters wide. The local population contributed to its realization, especially for the transport of granite from the Alzo quarry, on the opposite shore.