Diesel locomotive were classified as DET 1 and DET 2 (). Due to shortage of petrol products during World War I, they remained unused for regular service in Germany. In 1922, they were sold to Swiss Compagnie du Chemin de fer Régional du Val-de-Travers (), where they were used in regular service up to the electrification of the line in 1944. Afterwards, the company kept them in service as boosters till 1965. Fiat claims a first Italian diesel–electric locomotive built in 1922, but little detail is available. A Fiat-TIBB diesel–locomotive "A", of 440CV, is reported to have entered service on the Ferrovie
TU2 diesel locomotive trains. Later they were replaced by more modern designs. As of 2007, they are no longer in use on the narrow gauge railways in Russia, but some narrow gauge railways in Ukraine still use them. Many children's railways use TU2 locomotives too. The Aukštaitijos narrow gauge railway in Lithuania also still operates the TU2. TU2 is a diesel-electric locomotive. The main diesel engine is 1D12 and it produces 300 hp. The main engine drives the electric generator (195 kW) that supplies electricity to four traction motors, 62 kW each. TU2 diesel locomotive TU2 (ТУ2) is a Soviet narrow gauge diesel