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
M62 locomotive M62 locomotive M62 is a Soviet-built diesel locomotive for heavy freight trains, exported to many Eastern Bloc countries as well as to Cuba, North Korea and Mongolia. Beside the single locomotive M62 also twin versions 2M62 and triple versions 3M62 have been built. A total number of 7164 single sections have been produced, which have been used to build 5231 locomotives. According to the Comecon directives production of heavy diesel locomotives among Eastern Bloc countries was left exclusively to Romania and the Soviet Union. The first few prototypes of this heavy freight locomotive were ready in 1964 and their first