In the 1930s, when the Wehrmacht underwent major rearmament, first secretly and later openly, there was a need for various locomotives for use on the track systems which were operated directly by the Wehrmacht. This mainly concerned ammunition and fuel depots, training areas and airfields. In this environment, steam locomotives proved to be unsuitable for two reasons: on the one hand, flying sparks and ashes posed a risk of explosion and, on the other hand, in the event of war the steam plume of a steam locomotive could be spotted from a great distance. Although there were already fireless locomotives, these were only suitable for industrial companies in which larger excess amounts of steam were available. So the choice fell on diesel locomotives, even if the development here was still in its infancy.
At that time, diesel engines had already been introduced to aviation as sophisticated, supercharged two-stroke engines, and even the slow-running, simply constructed naturally aspirated engines had now developed sufficient power. It was the latter that were suitable for low-maintenance, uncomplicated use in shunting locomotives. Although there was still no agreement on the most suitable form of power transmission for large diesel locomotives, hydraulic power transmission proved to be suitable in the targeted power classes of the shunting locomotives. For this purpose, the Voith company from Heidenheim an der Brenz developed a torque converter transmission that also enabled several gears to be shifted for the optimum traction and speed in each case.
Two two-axle locomotives with an output of 200 and 360 hp each had now been developed. Both had a cab at the rear end and a narrower hood for the machinery. Some of the locomotives got an adapted exhaust system with additional explosion protection. The gearbox drove a crank axle, which was located between the wheelsets and drove them via coupling rods. Since the axle load of the more powerful locomotive had become too high for some areas of application, it was converted into a three-axle one. A four-axle variant was later developed, but only three prototypes were produced.
In addition to these three standard models, an additional locomotive with two or three axles was also developed, known as the WR 220, which, however, differed from the others due to its mechanical power transmission. The double locomotives of type D 311, which had electric power transmission and were intended for pulling railway guns, were significantly more powerful. At the other end of the power scale, a few locomotives were developed for the field railways, some of which were designed for use in trenches on the frontline and were built for gauges between 600 mm (nearly 2 feet) and 1,067 mm (3 ft 6 in). Large diesel locomotives based on the diesel-hydraulic standard gauge locomotives were developed but not built.
After the end of the war, some of the companies involved in the production of Wehrmacht diesel locomotives made more examples or, like Henschel, introduced new types that were very similar to the old models. Soon after, several West German companies created a new generation of locomotives that followed new standards, especially in terms of appearance and the arrangement of the machinery, but technically took over a lot from the old models. They all had the following features in common: a cab at the rear end of the locomotive or shifted slightly towards the middle, a large front hood and either a small or no rear hood for the machinery, hydraulic transmission from Voith with mostly two gears, a crank axle, transmission via coupling rods and two to four axles, all of which were mounted in the frame. Most manufacturers gave their locomotives designations similar to those of the prototypes, which indicated the installed engine power in hp.
Just as none of the Wehrmacht locomotives found their way to the Reichsbahn, almost no post-war models were delivered directly to the Bundesbahn. An exception was the V 65, which was derived from the MaK 650 D. Most locomotives came to private operators, mostly either light railways or industrial companies. The latter found many buyers, especially in the mining industry, since compact, high-power shunting locomotives were required there. The usually very robustly built locomotives also found export customers in the Third World, but state railways from Europe could also be won as customers. Many of the locomotives lived for many decades and were used well into the 21st century, some with new engines. Even today, not only are many preserved, some still regularly haul excursion trains and a few even have to earn money in regular service somewhere in the world.