For the narrow gauge railway in the Rhodopes with gradients of three percent and curve radii of 60 meters, the Bulgarian State Railways needed powerful freight locomotives. These were based on the Reichsbahn's class 99^73-76 and had slightly larger wheels to reach a speed of 45 km/h. The first five were delivered by BMAG in Berlin, another ten were built in Poland by Fablok due to the Second World War.

They fully met the requirements and were replaced by diesel locomotives of the class 75 in the 1960s. They were now used on other lines with lower gradients, where severe signs of wear showed up due to continuous operation at top speed. After eight locomotives were retired in 1977, the remaining ones were stored as a strategic reserve. Today four still exist, one of which is still operational.

During the Second Boer War, the British troops urgently needed powerful tank locomotives. Since the Natal Government Railways had already procured a ten-coupled tank locomotive from British production, the Reid Tenwheeler, they used this design and ordered 35 units as well. The order was divided between Dübs and Neilson, Reid in order to achieve a larger number in a short time. A visible difference to the NGR locomotives was the weatherboard on the coal bunker, which also offered protection from the elements when reversing. The military machines also attracted attention due to the brass parts on the boiler that were always polished to a high gloss.

after the rebuild to 4-8-2T

archive SAR

The first and fifth coupled axles were designed without wheel flanges for better maneuverability, which, however, was fatal to the locomotives in some situations. Especially when reversing, there were often derailments when entering tight curves or switches because the leading coupled axle had no wheel flanges. One attempted solution was to widen the wheel tyres, but this had only limited success. Despite this problem, the engines provided valuable service during the war until they came to the CSAR at the end of the war.

after the rebuilt to 4-8-0TT

Locomotive Magazine, December 1905

In order to really improve negotiation of curves and prevent derailments, it was decided, like the NGR, to remove the fifth coupled axle and thus convert six of the locomotives into a 4-8-2T wheel arrangement. A very large distance between the fourth coupled axle and the trailing axle was now visible, and the load on the trailing axle increased from just over four to just over six tons. With the formation of South African Railways they became Class E as tank locomotives were designated with letters. They were mainly used for shunting and were retired by 1966.

A sample of the former 4-8-0TT without side tanks in November 1974 in the Albion Mines

Dennis Mitchell

Another conversion was made in 1904, initially on one engine that was intended to increase the range that was too short in the eyes of the SAR. The last coupled axle and the trailing axle were removed together with the coal bunker, the frame was shortened accordingly and an additional tender was attached. Since the water tanks on the sides of the boiler had been retained, it was the design known in English-speaking countries as "Tank and Tender" with the wheel arrangement 4-8-0TT.

Since the second rebuild was successful, all remaining 28 engines were rebuilt in the same form and provided with surplus three-axle tenders. With the SAR they received the class number 13, since tender locomotives were designated with numbers. They were mostly used in the Witwatersrand region, where they were nicknamed “wallopers”, which means “wall runners” in Afrikaans. After their decommissioning, which was completed by 1961, some examples were sold to various mine operators. Some of these locomotives were used until the 1980s, after the side tanks had been removed from some in the meantime.

In the 1930s, the Müglitztalbahn in the Ore Mountains was converted from 750 mm gauge to standard gauge because more and more industrial companies were settling there and the narrow-gauge locomotives were no longer able to cope with the increased demands and the traffic on the road did not help. Now there was a need for a tank locomotive that could pull freight trains carrying paper, glass or metal goods. In addition to the maximum gradient of 3.6 percent, the curve radii were a challenge, reaching up to 139 m.

For this purpose, the class 84 was developed as a standard locomotive and initially delivered in two variants with different engines. The two examples from BMAG had a three-cylinder engine and a chassis with Schwarzkopff-Eckardt bogies. The latter were derived from the well-known Krauss-Helmholtz bogie, but here two coupled axles were connected. The running axle steered the second coupled axle, which in turn steered the first coupled axle with less deflection.

Two more pieces were delivered by Orenstein and Koppel, which had a Luttermöller axle drive. In this case, the outer coupling axles were designed to be laterally movable and connected to the adjacent ones via gear wheels. The running axles were mounted in a Bissel frame and these machines only had two cylinders.

Sectional drawing with dimensions

Die Lokomotive, September/October 1938

In the end, the design of the BMAG was convincing, whereupon eight additional ones were procured. They remained in service on the original route for the time being and eleven of the twelve survived the Second World War, but badly damaged after a bomb attack. After the war, the locomotives remained in the Ore Mountains, where they were used to transport uranium ore, among other things. Their decommissioning took place between 1966 and 1968. Some sources say that all machines were retired as early as 1958, that a planned reconstruction did not materialize due to the small number of units and that they were scrapped after a few years of service.

Since the conversion of the Höllentalbahn to adhesion operation was planned in the 1930s, a powerful tank locomotive with a high adhesive weight was required. This had to be able to pull the same loads as previous rack locomotives on the ramp with a gradient of up to 5.714 percent, but still run at modern speeds on less steep sections so that it can also be used in front of passenger trains. In order to meet the required performance, a decision was made in favor of a locomotive with a 2-10-2T wheel arrangement, in which the 20-tonne axle load possible on the Höllentalbahn was to be exploited. One consideration was to procure new examples of the Prussian T 20 or class 95 produced between 1922 and 1924. This was not implemented because the design of the T 20 was now considered outdated and its top speed of 65 km/h was not considered sufficient. In addition, an engine with three cylinders was preferred, since powerful two-cylinder locomotives tended to run very unsteady under full load on steep inclines.

The subsequently newly developed class 85 was created according to the principles of the standard program. Due to the small number of only ten locomotives, special attention was paid here to using not only individual standardized parts, but also complete assemblies from existing classes as much as possible. With a service weight of 133.6 tonnes and an axle load of 20.1 tonnes, it was to become the heaviest tank locomotive in the standard program. The power plant and chassis were taken from the pre-series models of the class 44, in which the inner cylinder acted on the second and the outer cylinders on the third coupled axle. The bar frame also consisted of 100 mm thick plates in order to be able to carry the heavy weight. As usual, a Krauss-Helmholtz bogie was used at the front end and weakened wheel flanges on the third coupled axle. The newly added trailing axle was integrated into a second Krauss-Helmholtz bogie. 

The boiler was borrowed from the class 62 passenger tank locomotive. Although it was powerful, the problem that is familiar with standard locomotives also occurred here that the locomotives with three cylinders had less power than their two-cylinder sisters because the design was not designed for the even distribution of steam to three cylinders. This resulted in only 1,500 hp, which was even less than the older and lighter T 20. Nevertheless, the top speed of 80 km/h enabled a wide range of applications according to the requirements. The ten engines were used almost exclusively on the Höllentalbahn, but there they were used to pull passenger and freight trains and as a pusher locomotive. The performance spectrum ranged from hauling a 1,970 tonne freight train on the flat at 50 km/h to climbing extreme inclines of 5.55 percent with a 165 tonne car load at 20 km/h.

Even after the Höllentalbahn was electrified, the locomotives were indispensable, since the 20,000 volts and 50 hertz used here was a different current system, which required specially converted locomotives. Thus, the time of the class 85 did not end until 1960, when the Bundesbahn converted the line to the usual power system. Only road number 85 007 was used for another year on a different route and was the only example that survived afterwards.

The class 95 was one of the heaviest and most powerful tank locomotives that the Deutsche Reichsbahn procured in its history. Since it was originally ordered by the Prussian State Railways as the T 20, it can often be found under this designation. The first ten examples were initially listed as class 77 until 1926 and only then reclassified as class 95. It was developed to haul heavy freight trains on main lines with a lot of gradients and to convert routes with rack and pinion to adhesion operation.

In order to be able to provide enough traction on the inclines, a very heavy and powerful boiler was placed on a chassis with a 2-10-2T wheel arrangement. This resulted in an adhesive weight that was greater than that of most ten-coupled tender locomotives. Since the steep stretches often had tight curve radii, both carrying axles were combined with the respective outer set of driving wheels to form a Krauss-Helmholtz bogie. The remaining axles could not be shifted sideways, but the wheel flanges of the middle driving wheel set were weakened. Thanks to the additional equipment with a Riggenbach-type counter-pressure brake, it was possible to brake on steep gradients without wearing out or heating up the wheel tyres. For the first time, gradients of up to seven percent could be overcome without a rack with just a few cars.

The locomotive was able to pull trains weighing 430 tonnes at 25 km/h on gradients of 2.5 percent, which was almost as good as the performance of the sixteen-coupled Bavarian Gt 2x4/4. In tests on the level, a little more than 2,000 tonnes could be pulled at 50 km/h, but in reality this was reserved for the heavy tender locomotives. 

95 0027 in June 1979 in Saalfeld

Werner & Hansjörg Brutzer

All of the 45 locomotives built survived the war. Only 14 of these made it to the Bundesbahn, which made them a minor class. In the beginning they were partly used as pusher locomotives on ramps, but the last of them was already retired in 1958. The 31 vehicles of the Reichsbahn were used on the low mountain range as powerful draft horses which were indispensable for a long time. 24 of these were converted to oil firing between the late 1960's and early 1970's and designated 95⁰⁰. The rest became 95¹⁰. Their service life ended in 1981 with the Sonneberg-Eisfeld route.

Since the existing 2-8-0 locomotives were no longer sufficient for the heavy ore trains in Lorraine, the Est was looking for more powerful locomotives. The 031+130 T Du Bousquet type, introduced in 1905, could not quite convince with their boiler performance in heavy freight train service. Thus, a new single-frame tank locomotive was developed that had sufficient power.

Thus, in 1913, two prototypes were created in the workshops in Epernay, which had been developed based on the existing passenger tank locomotives with 2-8-2 wheel arrangement. By reducing the driver diameter, a fifth coupled axle could be added, making it the first 2-10-2 locomotive and at the same time the heaviest tender locomotive in Europe. Known internationally as the Santa Fé, this wheel arrangement has since been referred to as the Lorraine in France. This is because these locomotives used in Lorraine were the first French locomotives of this type in France.

The engines had a Belpaire firebox, a Mestre-type superheater and a three-nozzle variable blast pipe. The leading and trailing axles were designed as bissel axles, each with 150 mm of side play, while all five coupled axles were fixed in the frame. Instead, the wheel flanges of the first and fifth axles were designed with a smaller depth, those of the second and fourth axles were weakened in width and the third axle had no wheel flanges at all. In addition to the two water tanks on the sides of the boiler, a third was integrated into the frame to get a water capacity of 13 cubic meters.

Both machines performed very well in test operations. With a train weighing 890 tonnes, 20 km/h could be reached at 1.5 percent, and the same speed was possible with 1,000 tons at one percent. Due to the First World War, no series engines could be procured for the time being. Only in 1925 and 1926 were 25 built, which received the numbers 5901 to 5925. Deviating from the two prototypes, these were delivered by Schneider in Creusot. The changes were only a few, but the sandboxes were no longer on top of the boiler, but housed inside the smoke box. In addition, sanding now only took place in front of the leading wheels.

They were first distributed to several depots in Lorraine. In 1930 they received new numbers from 151-701 to 151-727. After the creation of the SNCF, they were also stationed at other locations. During World War II they hauled suburban trains in Paris, which were now fewer but heavier. As early as 1947 they faced competition in the form of the A1AA1A 62000 series diesel locomotives and in 1957 only twelve were still in use. From 1957, five and soon eight examples were leased to coal mines in northern France. The last engines were retired by 1966 after they had been replaced by the BB 63500.

Side view

Die Lokomotive, December 1932

Schematical drawing with dimensions

Die Lokomotive, December 1932

Starting in 1930, the French Eastern Railway had a series of 2-10-2T tank locomotives built for heavy coal and ore trains. These came directly from the engines with the numbers 5001, 5002 and 5901 to 5925, which had brought the name “Lorraine” to this wheel arrangement in France. They took over the chassis including the axles and the boiler with Belpaire firebox from the previous series. However, the three-cylinder engine was taken over from the 2-10-0 tender locomotives with the numbers 150-001 to 150-195, which hab been built for the Est by SACM in Alsace since 1926.

The locomotives were initially only used in the east of the country, where they proved themselves in their intended purpose, even if the performance hardly excelled that of their predecessors. Due to the design with three cylinders, however, smoother running under heavy loads was to be expected. From 1938, they became the 151 TC 751 to 760 with the SNCF. Between 1950 and 1961, ten units were in service in the northern region, where they were used on the Paris circle line and north of the city. There one of their tasks was the supply of the power plant in Porcheville. Decommissioning did not begin until 1957 and the remaining machines still pulled heavy freight trains in the last few years before finally disappearing in 1966.

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.

The Sugar Pine Lumber Co., founded in 1923, was a logging railroad in the Sierra Nevada in California that called itself the “crookedest railroad ever built”. Nevertheless, they used locomotives with multiple driving axles in one frame. This started with four 2-8-2 saddle tank locomotives built by ALCO. In need for even more power, they even ordered a 2-10-2 saddle tank in 1927.

Given the number 5 and called “Minaret”, it must have been the heaviest saddle tank locomotive ever and most likely also the only 2-10-2ST. After the SPL shut down its operations in 1935, No. 5 was used by several construction contractors. One was the Mason-Walsh-Atkinson-Kier & Co., which used in in the construction of the Grand Coulee Dam and added an additional tender. The last operator was H. J. Kaiser Co., which scrapped it in 1947.