Decauville Trail (Bardonecchia – Val Fredda)

This beautiful dirt path was created from the site of an old industrial railway, known as Decauville, named after the engineer who invented this type of rail transport in the 1870s, Paul Decauville. In the 1920s and 1930s this railway on the Rochemolles torrent was used for the construction of the Sallarce dam and was part of the works that would lead to the electrification of the Frejus railway. To cross the Almiane river there is a notable wooden bridge.

The term Decauville is associated with the type of portable narrow gauge (600 mm) railway, presented to the world in 1878 by Paul Decauville.
The works for the construction of the road on which the small Decauville railway was to travel began in 1919 and ended in 1921. At the same time as the laying of the dirt road, a diversion channel was built, parallel to the road surface, which had the indispensable function of carrying the water to the three basins located in Frejusia. The cable of the dam-basins telephone line ran anchored inside the canal. The tracks were laid directly on the dirt road and stability was ensured by burying the sleepers. Due to the high risk of avalanches, the "railway" was only used in the summer period. The bridge over the Rio Almiane, still in operation in 1964, was completely dismantled and transported on small wagons to the Basins where it stopped for the whole winter. During this period, supplies and changes of guards took place inside the diversion canal which was emptied to allow passage.

From the book “Rochemolles – La Decauville, the dam, the road and the light” by Edoardo Tripodi and Walter Re

A slight slope along a part of the old industrial railway of Rochemolles (1915) with a narrow gauge (Decauville) built by the State Railways for the construction of the Sallarce dam, as part of the electrification of the Frejus railway

it.wikipedia.org/wiki/Ferrovia_di_Rochemolles