Construction began in 1907 but was not finished until 1927 because it was necessary to dig several long tunnels, including the Monte Orso and the Vivola tunnels, both of which are about 7.5 km long.
Der Bau begann 1907, dauerte aber bis 1927, da mehreren lange Tunnel erforderlich waren, etwa die Tunnel Monte Orso und Vivola, die beide etwa 7,5 km lang sind.