In the 1920s, there was a search for alternatives to the steam locomotive for railway traction, to reduce cost and improve efficiency.
[1] Between 1928 and 1929 FS steam locomotive number 910.042 was modified at the Royal Arsenal of La Spezia to test the system, which was based on the patents of the inventors Fausto Zarlatti and Umberto Simoni.
The boiler and superstructure were removed from the locomotive in the arsenal workshop at La Spezia but the original compound expansion steam cylinders were left in place.
This engine produced 325 hp at 450 rpm and drove a rotary compressor, built by a Swiss company in Winterthur, which delivered compressed air at 8 bar pressure.
A small naphtha-fired boiler with a heating surface of 52 square metres was also installed for the production of steam.