When a powerful freight locomotive was being searched that could still negotiate curves on the Black Forest Railway, Grafenstaden had the Class VIII c designed after the Mallet design. Only two pre-series locomotives were manufactured there, the production of all others was taken over by MBG Karlsruhe and Maschinenfabrik Esslingen.

Although the ability to negotiate curves was good, the rear axles, which were fixed in the frame, could hardly offer sufficient directional stability for the front bogie that could be shifted laterally due to their short wheel base. In addition to the tendency to slip, which was already present in mallet locomotives, the running smoothness was insufficient. Furthermore, due to the special construction of the running gear, the boiler was somewhat smaller than in comparable standard-design locomotives, which meant that the machines did not achieve the power of the classes VIII a and VIII b despite their greater weight.

Nevertheless, series production was ordered, and so twelve engines were built in Karlsruhe in 1895 and another 18 in Esslingen in 1899/1900. After the war, eight engines came to France and one to Belgium. The locomotives remaining in Germany were retired by 1925, which is why they were not re-designated as class 55⁶¹.

The BB I was a single Mallet locomotive with a 0-4-4-0 wheel arrangement, which was primarily used to push freight trains on the steep ramps in Franconia. The locomotive built by Maffei was originally intended for the Swedish-Norwegian railways, but was then taken over by the Bavarian State Railways. The Pfalzbahn also procured two identical locomotives in 1896 and designated them as class G 4^II.

In contrast to the BB II, which was later built in series, it was a tender locomotive, and it was also much heavier with an axle load of 14 tonnes. The rest of the structural design was similar, with vertical connecting pipes from the steam dome to the high-pressure cylinders in the middle and the low-pressure cylinders in the front. Like other four-axle Mallet locomotives, the machine was notable for its rough running and strong tendency to slip, which is why no more were procured. The same observations were also made at the Pfalzbahn with the two identical machines, whereupon these were only used in part to test new braking systems.

Both operators decided to use eight-coupled locomotives again in the future, as these did not have the weaknesses of the Mallets, despite the somewhat poorer curve running properties. The Reichsbahn number 55 7101 was reserved for a single remaining BB I, but this was no longer taken over due to the decommissioning in 1923. The Palatinate machine, which was still in use up to this point, suffered the same fate.

The problem on the Bavarian local railways was that there were very tight curves in some cases, and there were also many inclines and therefore increasingly more powerful locomotives were needed for the ever increasing requirements. For this reason, the BB II was developed, whose coupled axles were not in a common frame for better running characteristics in curves.

As a Mallet-type tank locomotive with only two axles each in the frame and in the bogie, it was ideal for the winding lines. Due to the lack of carrying axles, the running properties at line speed proved to be insufficient. In addition, the locomotive tended to slip and was therefore not always able to fully utilize its power.

Werner & Hansjörg Brutzer

Production consisted of a batch of 29 machines between 1899 and 1903 and a second batch from 1908, in which only two examples were made. The latter were slightly longer and heavier than the previous ones. They were all taken over by the Reichsbahn in 1925 and designated as class 98⁷. However, due to the shortcomings described, most of them were already retired in the 1930s. The remaining ones were sold to various works railways from around 1940, where the smooth running of the machines was not a problem. The former 98 727, which was sold to Südzucker AG in 1943, is now being kept operational by the Darmstadt-Kranichstein Railway Museum. Due to the advertising character of its former operator, it was nicknamed “Zuckersusi” (“Sugar Susi”).

Since the Hejaz railway from Damascus to Medina also had steep gradients and tight curves, a powerful locomotive was needed for freight trains. Since the tracks were also light with a gauge of just 1,050 mm, six axles were needed to achieve the necessary power. Since there was a lack of water along the route, the tender had to be big enough. The order went to Henschel in Kassel, where four Mallets were built to meet these requirements.

sectional drawing

flickr/Historical Railway Images

The six axles were distributed over two chassis groups, the first of which had only two coupled axles and one leading axle. The first coupled axle could also be moved laterally to improve running characteristics in curves. The two chassis groups were coupled to each other, which is not usual with Mallets. The locomotives apparently met the requirements and easily hauled 250-tonne trains over the entire route.

Shortly after the turn of the century, the Central Siberian Railway required powerful passenger locomotives for its winding mountain routes with light rails. In order to ensure sufficient mobility and to comply with the axle loads, the B^K was created in the Mallet design with a 2-4-4-0 wheel arrangement. Kolomna initially made five locomotives with compound engines and four with four equal-sized cylinders, which had a slightly larger boiler with a lower pressure.

103 more followed until 1909, all of which had compound engines. They were soon renamed to І by the Russian State Railways. They did not reach a larger number because they had a higher consumption and more complex maintenance than locomotives with a one-piece frame. Nevertheless, they remained in use for a long time, so that the last machine was not retired until 1954.