The Brigadelokomotive was a 0-8-0T tank locomotive built for the German military field railways with a gauge of 600 mm (nearly two feet). It was designed at the beginning of the 20^th century when it became evident that the 0-6-0+0-6-0T “Zwilling” was not powerful enough anymore. The first prototype was completed by Henschel in 1903, followed by a low volume production starting in 1905.

The locomotives had outside frames, outside cylinders and outside Stephenson valve gear. To enable running through tight curves, the first and last axles were Klien-Lindner hollow axles which could be adjusted radially. Later these were exchanged on some locomotives for conventional axles with weakened wheel flanges. With an indicated power of 75 hp, they could haul 70 tonnes with 15 km/h. Due to the limited water capacity of 1,100 liters, additional tenders were built with a capacity of up to 5,000 liters of water and 1.2 tonnes of coal.

Large-scale production only started in World War I, but at a large number of manufacturers. When production was completed in 1919, more than 2,500 had been built. With 789, the largest number had come from Henschel. Second and third were Borsig with 377 and O&K with 359. After the end of the war, they came to a large number of civil operators in many countries. Today, around 100 are still existing all around the world.

The Zwillinge (“twins”) were small tank locomotives that were built for the Bavarian and Prussian Heeresfeldbahnen (military field railways). What was special was that, in normal service, two technically identical, otherwise independent locomotives were coupled together back to back. The cab roofs were of different heights to allow for overlap. When the locomotives were used individually, they were also referred to as “Illing”. If necessary, an additional tender was attached.

More than 50 pairs were delivered to the Swakopmund-Windhuk state railway in German South West Africa, where the field railway construction command built a 600 mm gauge line through the Namib Desert. The Japanese Army Field Railway also received a total of 89 pairs in 1905 and 1906. Some Zwillinge from German South West Africa were also sold to Japan when the gauge was changed to Cape Gauge. Only a few examples were used for civilian purposes. The successor was the Brigadelokomotive, which, with four driving axles, was more powerful than a single Illing.

In the twenties, the ELNA (Engerer Lokomotiv-Normen-Ausschuß - Special locomotive standards committee) designed a range of standard locomotives to be built for private and light railways. The ELNA 2 was a 2-6-0T tank locomotive for light line service. Between 1925 and 1943, a total of 37 have been built. Among these were four built by Krauss, these differed in some aspects from the standard type.

The biggest customer was the Liegnitz-Rawitsch Railway with five locomotives. The ELNA 2 did not get a class number from the old Reichsbahn, but the East German Reichsbahn received 16 in 1949 and numbered them class 91⁶². One ELNA 2 that is still existing today is No. 146 of the Butzbach-Lich Railway.

In the twenties, the ELNA (Engerer Lokomotiv-Normen-Ausschuß - Special locomotive standards committee) designed a range of standard locomotives to be built for private and light railways. The ELNA 6 was the heaviest of these types and had the wheel arrangement 0-8-0T. With a top speed of 40 km/h, it was intended for all kinds of traffic on secondary lines and also for shunting. With a wheelbase of less than 4.5 meters, it did not need axles with lateral play.

Between 1922 and 1946, a total of 116 were built by different manufacturers since they were included in the war locomotive program as KDL 4. In this context, also Schneider of Le Creusot in France had to manufacture these and also continued production after the war for a total of 67. Thanks to the liberation of France, all 67 could stay in the country, came to the SNCF and were designated 040 TX.

In Germany, there was a total of four different variants. The standard type was offered in a cheaper saturated and a more powerful superheated variant, called ELNA 6 N and ELNA 6 H. Krauss of Munich could realize a cheaper production by using tooling already existing for other locomotives, so the seven locomotives resembled some other types which were in use in Bavaria. They also had larger side water tanks instead of the well tanks of the standard variant and were heavier. Additionally, seven of the locomotives produced by Henschel were of an augmented type that had a higher boiler pressure, larger cylinders and a larger superheater. These also had side tanks and were even heavier than the Krauss type. Later some got wheels with a diameter of 1.200 instead of 1.100 mm.

As the customers were private and light railways, most of them only got one to three locomotives. The largest customer was the Halle-Hettstedt Railway Company that got seven of which four came from Krauss. After the war, the West German locomotives remained in private ownership, while the East German ones were taken over by the Reichsbahn. Most were put into class 92⁶⁴, but three with a counter-pressure brake became class 92²⁹. Today three are preserved.

Although the large companies in industry and the mining sector mainly ordered diesel locomotives for shunting and transfer services after the war, steam locomotives continued to be built for these purposes. Since simple locomotives with saturated engines were sufficient here, Krupp included a six-coupled tank locomotive that had already been delivered in 1935 in the post-war program. Since this locomotive was then delivered to a fertilizer factory in Hürth-Knapsack, the type was given the name “Knapsack”.

In terms of size and weight, the locomotives roughly corresponded to the class 89⁰ standard locomotive, in terms of power they were somewhere between its saturated and superheated versions. With a wheel diameter of 1,100 mm, speeds of up to 45 km/h were possible and with an axle load of less than 15 tonnes, it could be used on almost all standard-gauge industrial railways. Of the twelve units sold in Germany, the largest order, five, went to a colliery in Neukirchen-Vluyn. Three more pieces were exported to Turkey.

Today there are still six units, one of which has been in service with the Hespertalbahn since 2000 and was parked at the end of 2016 when the deadline had expired. Currently, the Hespertalbahn states that the locomotive is being refurbished and will undergo a general inspection.

In World War I, the Halberstadt-Blankenburg Railway in the Harz mountains searched for a way to increase freight traffic on their rack lines which had a gradient of up to six percent. So they ordered two heavy 2-10-2T tank locomotives which could operate with adhesion only and so reach higher speeds. For greater safety when running downhill, they got cog wheels for braking which used the existing rack.

The second and fifth driving axles had side play of 30 mm, while the third one had no wheel flanges. To realize a huge power output, the boiler got a huge diameter of 2,000 mm at a tube length of only 3,700 mm. In the result, these two locomotives had no problems at all with the tight curves and could haul 260 tonnes with 12 km/h on six percent.

Two more locomotives were ordered, but without the braking cog wheels since they were found unnecessary after the trials. These had also been removes from the first two. The four got the names “Mammut”, “Wisent”, “Büffel” and “Elch” (mammoth, bison, buffalo and moose), hence the name “Tierklasse” (animal class).

The Reichsbahn numbered them 95 6676 to 95 6679. Since they needed more powerful ten-coupled tank locomotives to replace slow rack locomotives, the Tierklasse was used as an inspiration for the Prussian T 20. In 1949, all came to the East German Reichsbahn, where the boiler of 99 6679 (ex “Elch”) exploded only two years later. Only 95 6676 (ex “Mammut”) is preserved after its 1968 withdrawal and can today be found non-operational at Dresden.

Between 1950 and 1952, LKM at Babelsberg built 21 0-8-0T tank locomotives for a gauge of 900 mm. They were mainly intended for customers in the industry, like Wismut and for lignite mining. For ease of maintenance, they had no superheater and additionally, they were designed for the firing of lignite. Due to the small drivers and long overhangs, top speed was limited to 35 km/h or 22 mph. Despite this, three were bought by the Reichsbahn in 1958 for use on the Molli railway that connects Bad Doberan to the sea spa of Kühlungsborn. They became class 99³³. Two of these were superheated in 1961 and one is still operational and used in times of high demand.