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
Rigid-framed electric locomotive reluctant single prototype, built for comparison with the articulated 2′B+B1′ , which had themselves been a reaction to the poor performance of the 1912 1′D1′ . A rare example of the 2′D2′ layout was the unique British diesel-mechanical of 1955. Rigid-framed electric locomotive Rigid-framed electric locomotives were some of the first generations of design. When these began the s of these early locomotives, particularly with AC motors, were too large and heavy to be mounted directly to the axles and so were carried on the frame. One of the initial simplest wheel arrangements for a mainline electric locomotive, from around