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
ČKD T-669 diesel locomotive TE 006 traction motors are axle-mounted on the wheel sets. Located underneath the rear hood are batteries and a supply of sand. After modifications of the seating of the hood on the frame, the T 669.1 (771) and the wide-gauge version T 669.5 (770.8) were created at SMZ Dubnica. This class of locomotive, manufactured for Czechoslovak State Railways, Soviet Railways, and railways in Poland, Albania, India, Iraq and Syria numbers over 8,000 units, making it the largest series of locomotives ever manufactured in Czechoslovakia. ČKD T-669 diesel locomotive T-669.0 (770) class diesel locomotives, built by ČKD are six-axle, with two