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
TU2 diesel locomotive the Ways and Communications. The tests were successful, so the TU2 was taken into production. The only factory that produced the TU2 was Kaluga machine factory. The first three locomotives were tested again, in Panevėžys, (Lithuania) and Pärnu, (Estonia). During the tests, the locomotive could run as fast as . But due to the poor tracks on most of the country's narrow gauge railways, the highest allowed speed during normal operation was . TU2 diesel locomotives were produced till 1959; 281 locomotives were built. The locomotives were used on many narrow gauge railways to haul cargo as well as passenger