The OM range by Deutz consisted of small diesel shunters for industrial railways built in the thirties and early forties. They were powered by two-stroke engines with one to four cylinders. Their development focused on simple construction and cheap maintenance. Most had two axles, where one was powered by a chain and the other was connected to the first one by coupling rods. 

The most numerous model was the OMZ 122 R with 176 produced, where the Z stood for two (zwei) cylinders. While the 1 denoted the first generation of the engine and 22 denoted the cylinder stroke in centimeters, R stood for standard gauge (Regelspur). There were also narrow gauge variants like the OMZ 122 F that was developed for field railways and had a gauge of 600 mm. It only had half the weight of the standard gauge variant and a somewhat lower power.

Three different types of diesel locomotives were built for the Heeresfeldbahn, which had around 50, 130 and 200 hp and had two, three and four axles. The locomotives had an external frame and were developed in such a way that they could be built for different gauges or subsequently converted. The engines were all robust, non-turbocharged diesel engines designed for low-maintenance operation. While the smallest had mechanical power transmission and chain drive, the larger ones had hydraulic transmission and drive via jackshaft and coupling rods. 

With the three-axle HF 130 C, the power came from different 6-cylinder in-line engines that had between 120 and 130 hp. It was built ex works for gauges of 600 and 750 mm. Locomotives named HK 130 C were also developed for Africa for the Cape gauge of 1,067 mm used there, but due to the course of the war they were not used there and were then re-gauged to 600, 750 or 900 mm. After the war, many of the approximately 350 units built came to various narrow-gauge and factory railways in Germany, Austria and Czechoslovakia. The last units built were delivered from Gmeinder to the Wangerooge island railway between 1952 and 1957. In Austria some were converted to the Bosnian gauge of 760 mm. To this day there are still many locomotives that are kept ready for use by the Rügen light railway or several clubs, for example.

These locomotives were developed from 1930 to take on light shunting tasks at small stations. In 1931 it was defined that power group I should consist of small locomotives with an output of less than 40 hp. A few locomotives were initially ordered between 1931 and 1934, which the four manufacturers Jung, Orenstein & Koppel, Windhoff and Gmeinder had developed independently of one another. These could be obtained cheaply and served their purpose, but they were all built differently.

For this reason, a standard design was created in 1934, the vehicles of which were identical except for different diesel engines. The first variant had an operating weight of eight tonnes and, depending on the engine, an output of between 25 and 30 hp. In 1935 and 1936, a reinforced standard design with 35 to 40 hp was created. The power was transmitted in a very simple way via chains from the gearbox to both axles. Its designation was Kö I, which stood for “Kleinlokomotive mit Ölmotor” (Light locomotive with oil engine). During the war some were converted to run on LPG and then designated Kb I.

The cab was at the rear, but the hood was so small that it was easy to look past. In the driver's cab there was a control panel in each direction to make maneuvering in both directions easier. At both ends there was a very simple form of shunting coupler that coupled automatically and was released with a foot pedal. A braking system operated by compressed air for the entire train was also dispensed with, only the locomotive itself could be braked using a foot brake. A curiosity is that the locomotives of the first series were not allowed to leave the stations because they weighed eight tonnes and were too light to trigger some contacts. The reinforced models no longer had this problem with their ten tonnes.

After the war, the examples of the first series were quickly retired. The rest received 50 hp Deutz tractor engines between 1954 and 1962 and other standardizations. Nevertheless, their possible uses shrank as parcel traffic continued to decrease. They were now too weak to move the heavier unit trains, which is why in 1968 only a smaller number were included in the new numbering scheme as class 311.

At the Reichsbahn they only received new engines and from 1970 they became the class 100⁰. Here, too, most of the locomotives were decommissioned in the seventies while new small locomotives of performance class II were being built.

In addition to the small locomotives of power class I, a more powerful variant was also produced. The definition of power class II provided for an engine output of between 50 and 150 hp. A total of 65 prototypes were made by a large number of manufacturers before the final, standardized design for the series was determined in 1932. Although these looked very similar on the outside, there were different drive concepts.

Most of the locomotives drew their power from a diesel engine, but several also had the benzene or Otto engine that was common in railcars and small locomotives at the time. Either a hydraulic transmission, a mechanical manual transmission or, in some cases, an electrical power transmission served to transmit the power. Individual pieces were built with steam engines or as electric storage locomotives. The designation of the locomotives consisted of a K for “Kleinlokomotive” (small locomotive), an ö or b for diesel (oil) or benzene engine and f, e or no additional letter for hydraulic, electrical or mechanical power transmission. The steam locomotive ran as Kd and the storage locomotives as Ka or Ks. Finally, Roman II followed for the power class. The Köf II was selected for series production, i.e. the variant of the diesel locomotive with hydraulic transmission. 

As with the Köf I (which was actually only introduced later), great importance was attached to simplicity and a compact design. Initially, a braking system based on pedal force was used because the loads being pulled were small. The doors were also initially open, which also had the advantage of quick entry and exit when shunting. The low body made it possible to load the slow vehicles onto freight wagons and move them to another location without exceeding the regular loading gauge. 

These locomotives were used for a very long time on both sides of the Iron Curtain. The Bundesbahn even built more than 700 new Köf II with some improvements. The main changes were engines with 128 hp, air brakes and a closed driver's cab. The existing pieces were gradually rebuilt until 1974 so that they largely corresponded to the new builds. The last of the Bundesbahn locomotives, later designated as the class 323, were retired by DB AG in 1999.

In the GDR, only a few individual pieces were made as replicas, but LKM Babelsberg used the basic design as the basis for the N3 and N4 models with only 60 or 90 hp. Later, also based on the original model, the V 10B, V 15, V 22 and V 23 were created, each with an output of between 100 and 220 hp corresponding to the designation. Most of the pre-war locomotives were given a mechanical gearbox and from 1970 they were classified as class 100. More than 300 of these were included in the renumbering plan of the combined DB AG, but in contrast to the Bundesbahn machines, they were classified as class 310.

When considering the development of the optimal form of propulsion for light shunting locomotives, the idea for a dual-powered locomotive with electric drive and a diesel engine to charge the battery came up. The basic idea was that these locomotive only need a large part of their maximum output to get a train moving, so that a weaker unit would suffice for charging. In 1933, road number V 16 004 was created as a test model for the new type of power plant. It was a three-axle locomotive with three nose-suspended motors of 50 kW each. These were powered by a battery that was charged by a four-cylinder Deutz diesel engine.

Analysis of operation with conventional shunting locomotives led to the conclusion that the machine to be developed would require an average of around one-fifth to one-tenth of its maximum output over the entire period of use. It was therefore sufficient to compare the 150 kW total output of the electric motors with a diesel unit of only 55 kW. In order to ensure the best possible conditions for the engine driver when shunting, the driver's cab was installed in the middle of the locomotive. It was thus located between two hoods of approximately the same size and had two driver's desks. The diesel engine and 64 of the 160 cells of the battery were in one of the hoods, and the remaining cells in the other.

During the test phase, which lasted several years, the one-off proved itself excellently in the shunting of trains weighing up to 600 tonnes. Due to the war preparations, however, series production did not take place and road number V 16 004 was finally parked. The engine was later used by the Reichsbahn of the GDR at several train stations in Berlin. A general overhaul took place in 1957, which brought with it a new diesel engine and new battery cells. From 1960, the designation was changed to road number A 20 090. A short time later, the locomotive was rented to a concrete works before it was sold to a housing construction company in 1966 and finally scrapped in 1977.

The Wehrmacht procured four diesel-electric double locomotives, which were to transport the gigantic 80 cm guns to their place of use and align them in position. These guns weighed 1,350 tonnes and required several trains to transport them. Four double locomotives were completed, two more were destroyed during construction.

The guns were not railway guns in the true sense of the word, but rather stationary, which were only transported by rail and had to be set up on site. There, the crews of several construction trains created a huge emplacement with a double-track curved line to align the cannon. Although the fine alignment was done by electric motors under their own power, the locomotives were needed to move them on the curve of the track. Two of these double locomotives were provided for this purpose, which, thanks to their electrical power transmission, could also supply the current for the gun.

Each half had an inline six-cylinder MAN engine that produced 691 kW (940 hp). Each of the four axles mounted in a frame had its own nose-suspended motor. A maximum speed of 75 km/h could be reached for transport to the position or other journeys.

After the machines had only been used once during the war at Sevastopol, the Bundesbahn subsequently took over two double units in their fleet and kept a third as a spare parts donor. In order to improve performance in freight transport, two Maybach V12s, each with 808 kW, were installed, as they were also used in the modern V 200. The locomotives were given the same red paintwork as the new-build locomotives and, according to the current scheme, were designated V 188 due to their original 1,880 hp total output. With the new scheme of 1968, they became the class 288, but the first locomotive was retired in 1969 and was not given a new number. The original D 311 04 and later V 188 02 a+b was renumbered 288 002 and was kept in stock until early June 1972.

The WR 200 B 14 was the smallest of the standard Wehrmacht locomotives and, with 129 units, not quite as common as its three-axle sister. The designation stands for “Wehrmachtslokomotive standard gauge, 200 hp, wheel arrangement B, 14 tonnes axle load”. It is also known under the designation V 20, which it received from the two German railways after the war. The locomotives were never used by the Reichsbahn before the end of the war because they were directly assigned to the Wehrmacht.

Characteristic of her appearance was the driver's cab at the rear end and the high hood, which contained all the machinery and was provided with several flaps for access to the engine room. Compared to the later V 36, the body was lower overall and the entire two-axle locomotive was over a meter shorter. Various six-cylinder in-line engines from Deutz, the Mannheim Motor Works or MAN provided the drive. The power was transmitted via a hydraulic transmission to a jackshaft between the axles, which in turn drove the wheel sets via coupling rods. A coke oven was installed for starting at low temperatures.

After the war, not many examples made it into state railway service and only 23 locomotives remained in service with the Bundesbahn, four with the Reichsbahn and one with the ÖBB. While the DB only removed the coke ovens, the DR machines got new engines with the same power. Today some are still preserved and partly also operational.

The Wehrmacht locomotive that stood out alongside its sisters with 200 and 360 hp was the WR 220. It was ordered by the Luftwaffe and, unlike the others, had mechanical power transmission. There was a two- and a three-axle variant, designated WR 220 B and WR 220 C, respectively. The two-axle had an wheelbase of 2.90 meters and the jackshaft was located between the axles. With the three-axle, the overall wheelbase was only five centimeters longer and the jackshaft was in the narrower space between the second and third axles. The wheel diameter was five centimeters smaller here, but whether this was only chosen to accommodate the third axle or for other reasons can only be guessed at. Compared to the WR 220, both were slightly shorter and had a larger cab.

After the war, the Bundesbahn took over nine two-axle and five three-axle vehicles, which were classified as V 22 according to their output. Since these locomotives differed from the V 20, which was available in large numbers, an adaptation was sought. This was implemented on all two-axle vehicles between 1951 and 1953 by installing a new engine and hydraulic transmission. In 1968, these were even given computer numbers with the class 270 and were used from then on for about ten years. One of the three-axle locomotives was converted to two axles. However, since this apparently did not deliver satisfactory results, the other three-axle vehicles were retired until 1951.

The WR 360 C 14 was the Wehrmacht's most well-known diesel locomotive and was built in the largest numbers. The original designation stood for “Wehrmachtslokomotive Regelspur, 360 HP, wheel arrangement C, 14 tonnes axle load”. However, the name V 36, under which it was used on both sides of the inner-German border after the war, is more familiar to the public.

It was powered by a six-cylinder in-line engine with 360 hp. This did not require turbocharging and drew its power from a displacement of 98 liters, which reduced production costs and minimized technical defects even under difficult operating conditions. Most examples used a multi-speed hydraulic gearbox to transfer power to the jackshaft, but some also used a mechanical gearbox. The production of the WR 360 C 14 comprised a total of around 280 units, some of which remained in other countries after the war. In Germany, 42 pieces went to the Reichsbahn and almost 100 to the Bundesbahn. Further examples were also built after the war, and new types of diesel locomotives were created primarily for private and works railways, which were more or less based on this model.

In the Bundesbahn, the V 36 was not only used for shunting, but often also on secondary lines with passenger trains. Since the poor visibility due to the high hood proved to be a disadvantage when used on the line, conversions were also made. The best known was a tower on the driver's cab roof, with the driver standing on the driver's desk and having a better view of the route. A completely new high cab was built for the V 36 238, but this was the only example. Some V 36s were also modified with regard to the controls. In order to allow push-pull operation with control cars from multiple units, a number of machines were given push-pull control. Systems were initially used that required an additional man on the locomotive and only later variants were suitable for one-man operation. In addition, some locomotives were given multiple controls so that two V 36s could be coupled together at the cabs and manned by one driver.

When the changeover to computer numbers was made, V 36s were still existing in both German states. Since 1968 they have been known as class 236 in the Bundesbahn and as class 103 in the Reichsbahn since 1970. The former was phased out in the 1970s, the latter in the 1980s. Today there are several locomotives, some of which are roadworthy and some of which are used regularly.