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
Electro-Motive Diesel 567 engine, introduced by their renamed Cleveland Diesel Engine Division in 1938. The new engine upgraded the horsepower of EMC's E series locomotives to 2000 per locomotive unit and increased reliability substantially. Also in 1938, EMC started to increase its reach up the chain of locomotive production by transitioning from General Electric equipment to in-house produced generators and traction motors. With Eugene Kettering moving to EMC that year, EMC moved into a leading role in further development of GM's locomotive engines. GM-Winton-EMC's long development efforts put the company in an advantageous position relative to other developers of Diesel-electric locomotion. Their