Diesel locomotive break down. Hydraulic transmission for locomotives was developed in Germany. There is still debate over the relative merits of hydraulic vs. electrical transmission systems: advantages claimed for hydraulic systems include lower weight, high reliability, and lower capital cost. By the 21st century, for diesel locomotive traction worldwide the majority of countries used diesel–electric designs, with diesel hydraulic designs not found in use outside Germany and Japan, and some neighbouring states, where it is used in designs for freight work. In Germany and Finland, diesel–hydraulic systems have achieved high reliability in operation. In the UK the diesel–hydraulic principle gained a poor
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