A few years before the First World War, Jean-Baptiste Flamme developed a very powerful boiler that was to be installed in a goods and an express locomotive at the same time. From 1909 the type 36 with 2-10-0 wheel arrangement and from 1910 the Pacific of the Type 10 came into existence. The boilers differed only in the firebox, which had enough space between the last coupled axle and the trailing axle on the type 10, but had to be accommodated above the last two coupled axles on the type 36.

The very large firebox had a direct heating surface of 19 square meters and included a grate of 5.1 square meters. The long boiler tapered in front of the firebox, but still had a large diameter in the front area. It made the Type 36 the most powerful goods locomotive in Europe.

To ensure running in curves, the leading axle was combined with the first coupled axle to form a Zara steering frame, and the last coupled axle could be moved 29 mm to the side. The four cylinders were all in one plane and were only controlled by two external Heusinger valve gears for easier maintenance. The inner cylinders acted on the second coupled axle, and the outer ones on the third.

In a first series, 136 pieces were completed, 17 more followed after the First World War. 113 of the pre-war machines were rescued to France during the war, where they were not used due to their high axle loads. As early as 1915, 60 units were sold to Russia, where they were to be used on standard-gauge routes in Eastern Europe. Ultimately, they were converted to broad gauge and used in the Soviet Union until 1962.

The engines returned to Belgium were fitted with double blast pipes and longer smokeboxes in the 1920s. Together with other smaller conversions that were made up to the early forties, the service weight increased by almost four tons and the power to 2,300 hp. They were now designated type 36^bis and were used until 1947.

The class 9F goods locomotive was built from 1954 as the last and most powerful of the standardized steam locomotives from British Railways. This was ordered when extensive electrification of the British railway network was still considered realistic and powerful steam locomotives were needed for the transitional period. After Robert Riddles had already developed the 2-10-0 wheel arrangement war locomotives for the War Department, he also developed the 9F. This wheel arrangement was chosen because of the greater adhesive weight after initially wanting to develop a locomotive with a 2-8-2 wheel arrangement.

No. 92151 in July 1961 in front of the “Pines Express” at Haresfield, Gloucestershire

Ben Brooksbank / Down 'Pines Express' passing Haresfield station.

A goal in the development was to realize the greatest possible power, taking into account the British loading gauge and a relatively low axle load. The five coupled axles were able to negotiate curves by designing the wheels of the middle coupled axle without a wheel flange and by providing the wheels of the second and fourth axle with weakened wheel flanges. It was soon found that the locomotives with this axle arrangement ran very well at higher speeds, despite the fact that the coupling wheels were only five feet in diameter and they had two cylinders. In the course of production, the output was further increased with a double chimney. Adaptations such as a Franco-Crosti boiler and mechanical stoker were less successful and were not used in large numbers.

No. 92203 “Black Prince” in 2010 at Toddington

Tony Hisgett / Black Prince 6

Like many more powerful British goods steam locomotives, the 9F also had to be used to pull express trains in heavy excursion traffic, especially on weekends. There are credible reports of runs where the locos hit just over 90 mph. A total of 251 examples were made by March 1960. Number 92220 “Evening Star” was the last steam locomotive built for British Railways and was also the 999th standard steam locomotive. This example was not decommissioned even after the steam ban in 1968 and was used without interruption for excursions until the 1980s. Today it is a static exhibit, while eight more of its sisters, which were retired until 1968, were also preserved and some are still running today. One of these, No. 92203 “Black Prince”, pulled the heaviest train in Great Britain ever hauled by a steam locomotive in 1982 at 2,178 tons.

The class 42 or KDL 3 war locomotive was a compromise between the class 52 war locomotive (KDL 1) and the class 44 heavy freight locomotive. It was developed because the class 52 did not always have sufficient power for heavier freight trains, but the axle loads of the bigger sister were too high for many routes. Austria, which was annexed in 1938, and Poland, which was conquered later, were to be the preferred areas of operation.

As a basis, a boiler with the same dimensions as that of the 44 was used and placed on the chassis of the 52. Only two cylinders were used as power plant, which resulted in very rough running when operating at high speeds and when the entire power was called up. The construction of the boiler of the two pre-production models from 1943 corresponded to the Brotan design developed in Austria. Since this did not provide the desired performance, a conventional boiler was used in series production from 1944. Compared to the class 44, the smoke tubes were shortened to save weight.

In use, the typical weaknesses of the war locomotives, which were partly caused by poor quality production, quickly became apparent. Some locomotives had so many defects that they had to be parked damaged after a test run. The closed driver's cab offered protection from the cold in winter, but also led to unbearably high temperatures in summer. In addition, the two jet pumps were installed inside the driver's cab and generated additional heat.

Production took place at several manufacturers in Germany, Austria and Poland, who were combined in the Gemeinschaft Großdeutscher Lokomotivfabriken (Community of Greater German Locomotive Factories). Due to the course of the war, however, the target of initially 8,000 and later 3,300 locomotives could not be achieved. Only 844 examples were completed by the end of the war. After the war, there were not only many examples of this series in Germany, but also in Poland and Austria larger numbers were ready. Some were also scattered in other countries. However, as most of these were in very poor condition, a lot of work had to be done before they could run again.

Simultaneously with the repairs, there were efforts in the post-war period to improve the structural defects of the war locomotives through conversions. In addition, there were still unfinished locomotives in many places, from which further examples were created. Thus the total number rose to 1,061 by 1949. Since there were a large number of steam locomotives that were not so greatly simplified in German-speaking countries, the class 42 did not last very long there. The decommissioning at DB, DR and ÖBB took place in 1962, 1969 and 1968. The last examples, designated as Ty43 there, retired from service in Poland in 1995.

The two-cylinder class 43 and the three-cylinder class 44, both with single steam expansion, were the first freight locomotives from the standard program. The 44 was designed to tow 1,200 tonnes on low mountain lines with moderate gradients and 600 tonnes on steep ramps. In addition, ore trains weighing up to 4,000 tonnes should be able to be handled double-headed. With an axle load of 20 tonnes, it could only be used on well-developed main routes.

While the two outer cylinders acted on the third coupled axle, the middle cylinder was installed at an angle and connected to the second coupled axle. Measuring 600 by 660 mm, the cylinders developed considerable power. The boiler was essentially taken over from the 01 and also had a wide firebox, which was above the coupled wheels. The maximum permitted speed was 70 km/h.

In 1926 only ten pre-production machines were built. Since the class 44 consumed a lot of steam compared to the 43 and also had too high an axle load, the decision was initially made in favor of the 43 and no further production of the 44 followed. In 1932 and 1933, the 44 011 and 44 012 were built, their boilers being operated with a medium pressure of 25 bars and with a four-cylinder compound engine. These are not considered optimally designed because the cross-sectional ratio between the high and low pressure cylinders was too large at 2.6. It remained with these two vehicles, one each of which went to the Bundesbahn and Reichsbahn after the war and were used for several decades.

Former Übergangskriegslokomotive as 150 X of the SNCF

SNCF

Series production of a lighter variant only began in 1937, which only had a cylinder diameter of 550 instead of 600 mm and a boiler pressure of 16 instead of 14 bars. Production peaked during the war to cope with the increased freight volumes. From 1942, probably starting with road number 44 786, production was switched to a “Übergangskriegslokomotive” (transitional war locomotive). Some materials were replaced by indigenous materials and some simplifications were made. This included the omission of the smoke deflectors and the front side windows of the driver's cab.

During the war, other locomotive factories were obliged to build the class 44, including some in the conquered areas. In addition to Fablok in Poland and Frichs in Denmark, these included a particularly large number of French companies. By the end of the war, 1,753 machines for the Reichsbahn had been completed. After the liberation of France by the Allies, production continued there and a further 226 were made. In the GDR, ten were made using boilers that were left over from Frichs.

The Bundesbahn had received the largest part with 1,242 pieces. Although at least 291 machines, most of which were built in France, had to be handed over to France as reparations, the class 44 formed the backbone of heavy freight traffic on the Bundesbahn. The locomotives were given the nickname “Jumbo” and were initially barely changed apart from the replacement of the smoke deflectors. A total of 36 machines were converted to oil firing, mainly in 1965 and 1966, in order to increase performance and economy while relieving the fireman. The oil-fired locomotives were classified as the class 043 from 1968, while the coal-fired locomotives became the 044. The importance of the locomotives decreased when the main routes were increasingly electrified or converted to diesel traction. The decommissioning took place between 1970 and 1977.

Sectional drawing with dimensions

Railway and Locomotive Magazine, October 1926

The Reichsbahn in the east received 335 units, significantly fewer than the Bundesbahn. Of these, 97 were converted to oil firing and 22 to pulverized coal. The unconverted locomotives were taken out of service by 1974 after diesel and electric locomotives were introduced on the low mountain ranges. In view of the oil crisis in the early 1980s, most of the oil-fired locomotives were converted back to coal-firing, but they were rarely used.

After the war, apart from Germany and France, there were 67 in Poland, three in Czechoslovakia, 16 in Austria and one in Belgium. With more than 70 pieces, the whereabouts could not be traced. Today there is still one operational example in Germany and the Netherlands each. 15 more are still preserved, but no longer roadworthy.

The class 50 was developed to be able to replace the heaviest freight locomotives with low axle loading from the various state railways. With the wheel arrangement 2-10-0, it has a considerable size, but due to the axle load of only about 15 tonnes, it could be used on almost all secondary lines. The most important class to be replaced was the Prussian G 10, which was present in very large numbers. Compared to this, only one leading axle was added in order to be able to increase performance despite the same axle load. 

The general design of the 50 was aimed at being able to manufacture larger numbers for a low price in many different factories. After the beginning of the war, the idea arose of the war locomotives or “Kriegslokomotiven”, which should be even simpler. To this end, individual assemblies were increasingly being replaced by simpler ones, for example by using disc wheels instead of spoked wheels on the leading axle or by using an easier-to-manufacture, angular sandbox. These machines were designated as transitional war locomotives or “Übergangs-Kriegslokomotiven” (ÜK) and formed the basis for the later Kriegslokomotive 52, which was very simply constructed from the start.

The problem with such a long locomotive on branch lines was often that there weren't enough turntables available or there weren't any at all, since mostly only tank locomotives were used there. For this reason, soon the tub-like tender developed for the 52 series was introduced, which also allowed reverse speeds of 80 km/h or 50 mph. 

After large parts of Europe were occupied by the National Socialists, the construction of the class 50 was introduced in many locomotive factories in the conquered countries. Even after the war, production continued until 1948, so that in the end 3,164 pieces were completed. After the war, a very large number of the 50 were still available in various countries, where they continued to be used for a long time. In Germany, the majority of 2,159 operational machines remained in the western zones and only 350 were still operational in the Soviet occupied zone. Other user countries were Poland, Czechoslovakia, Austria, Bulgaria and Denmark. In Romania, 282 replicas were made as the 150 series until 1959.

For a long time, the 50 remained the most important freight locomotive on routes with lower axle loads on the Bundesbahn. Some conversions were made, including some where the boilers of the class 52 were installed. These were made of an alloy that did not age as quickly, but the 52, with its greatly simplified assemblies, could not compete with the 50 in terms of power. A visually striking conversion was the replacement of the large Wagner smoke deflectors with smaller Witte-type smoke deflectors on almost all machines. In a large number of engines, the tender was equipped with a driver's cab. When computer numbers were introduced in 1970, the running numbers could only have three digits, and so the 50 became the series 050 to 053.

At the Reichsbahn in the east, freight train service was more concentrated on the larger numbers of class 52 units. Nevertheless, 208 units were later reconstructed as class 50³⁵, which will be described separately. With the 50⁴⁰, new locomotives were developed on the basis of the 50, which will also be the subject of a separate article. Finally, oil-fired conversions were designated as 50⁵⁰, of which 72 pieces were made. Since they were used more intensively due to their higher performance, they suffered from higher wear and were withdrawn in the early 1980s in perspective of the oil crisis. The last few examples of the class 50 were retired from the DR in 1987.

Due to the large number, many examples of the class 50 can still be found in various countries today, and a large number of them are still roadworthy. These are often used in front of special trains and some of them are used in this role all year round. Occasionally there are also events where the old freight train locomotives can be found in front of commercial freight trains , in accordance with their original purpose.

Even before the start of the reconstruction program, the Reichsbahn began procuring new freight locomotives to replace outdated Länderbahn locomotives and worn-out war locomotives. What was required was a machine with an axle load of not much more than 15 tonnes that could be used universally. Since it was not possible to procure the Czechoslovak class 556.0 due to political problems, a new machine was developed on the basis of the class 50. Care was taken to use as many identical parts as possible with the class 23¹⁰ built at the same time.

In terms of frame dimensions, the class 50⁴⁰ was almost identical to the classes 50 and 52. As with the war locomotives, a plate frame was used, which was too weak for the strains which were posed upon them later. The boiler was a new design with a combustion chamber and mixing preheater, which had about 150 hp more than that of the class 50. This was later also used on the classes 50³⁵, 58³⁰ and 52⁸⁰. Trofimoff valves were used for better idling characteristics.

Originally, the procurement of 350 locomotives was planned. However, production was discontinued in December 1960 after only 88 locomotives had been completed, presumably because of the reconstructed locomotives. Road number 50 4088 was the last standard-gauge steam locomotive to be newly built in Germany. As early as 1968, the class 50⁴⁰ was only in use in the area of the Reichsbahn division in Schwerin. It was not until 1980 that the last one was retired. Road number 50 4073 in Nördlingen is the only machine that has survived to this day. It is being rebuilt since 2016, has been in the Meiningen steam locomotive works since June 2022 and could be operational again as early as 2023. Road number 50 4088 should also have been preserved, but this had to be abandoned after an accident.

After initial attempts with the Franco-Crosti boiler on the class 42 were unsuccessful due to corrosion damage, a new attempt was made in 1954 on a class 50 locomotive. Since this enabled a coal saving of 22 percent to be achieved, 30 other locomotives were converted in exactly the same way in 1958 and 1959. One problem was the smoke from the central chimney, which was improved with a wind deflector. As early as 1961, corrosion damage to the boiler was also found on these locomotives. Since the conversion measures now required were more expensive than the savings in coal, the locomotives were retired by 1967.

After the class 50 had been gradually simplified in the course of production, the structurally very similar class 52 was designed from the ground up as an even simpler war locomotive. Compromises were made at the running smoothness and compromises in power were accepted in order to obtain a locomotive that could be manufactured as quickly and cheaply as possible and was easy to maintain. The measures used were summarized with the official term “Entfeinerung” (“de-refinement”). In addition, production could be rationalized to a large extent on the basis of the initially planned 15,000 vehicles.

Although the 52 looked similar to the 50 on the outside, a different approach was taken when manufacturing the frame, using a plate frame that was no longer widespread at the time but was easier to manufacture instead of the bar frame. A few examples represented a deviation, in which bar frames were installed that had originally been produced for other locomotives. In addition to the direct simplification of some assemblies, attempts were generally made to switch to simpler production methods. For example, previously forged parts on the connecting and coupling rods were replaced with cast ones. Although this resulted in poorer fitting accuracy and durability over the long term, it was assumed that once the war ended well, the worn out war locos would no longer be needed and that the more mature standard locos would be sufficient.

In addition to simplifications, considerations about the use of the locomotives also flowed into the development. Since it was also assumed that it would be used extensively in the Soviet Union, the driver's cab was closed to protect the crew from the cold. This resulted in the further advantage that one was protected from the wind even when reversing. A new approach was also taken with the tender. Instead of the box-shaped tenders with a separate frame and body that had been customary up to that point, the tub-type tenders, which were clearly recognizable to the eye, were developed. They got their name from the tub-shaped water tank, which also served as a self-supporting basic structure. In addition to these, some machines were created as condensation locomotives, which carried a four- or five-axle condenser tender. These proved particularly useful in the extensive eastern areas of the conquered territory, since a regular supply of fresh water often proved very difficult there. Another positive effect in times of war was that the locomotives did not trail a steam plume that could be seen from afar.

In order to rationalize production, advantages that had resulted from the large number of locomotives were used. In contrast to the past, not every factory was allowed to produce the majority of the assemblies itself, but rather a large number of standardized components were produced by one factory and assembled at a different location. In order to be able to implement this project more easily, the manufacturers joined together to form the Gemeinschaft Großdeutscher Lokomotivhersteller (Association of Greater German Locomotive Manufacturers, GGL). Some important leaders from politics and industry took part in this, of which Albert Speer was the best known. The targeted 15,000 pieces could not be reached due to the defeat in the war, but up to this point 6,161 pieces had been made. These were scattered across large parts of Europe and there was also a large number of unassembled assemblies, so that around 300 more locomotives could then be completed in various countries. Together with complete replicas, it is assumed that a total of over 7,000 pieces were made.

Many countries continued to use the class 52 locomotives after the war, sometimes in such large numbers that they were indispensable for a long time. By far the largest part was received by the Soviet Union, which received more than 2,000 units either as spoils of war or as reparations. In addition to some that were completed later, the existing ones were regauged to 1,520 mm gauge and fitted with central buffer couplings. They were given the designation ТЭ and were available as a reserve in some regions until the 1990s.

Furthermore, Poland received about 1,200 locomotives, which were later supplemented with a few more purchased from the Soviet Union and designated as Ty2 or Ty42. Austria also took over a larger number with 700 units and used them as classes 52 and 152 until 1977.

In Germany, after the end of the war, there were 700 units in the western zones and 1,150 in the eastern zone. At the Bundesbahn there was the fact that many of the more mature standard locomotives could be saved to this area before the end of the war and so there was no great need for the class 52. So most of them were decommissioned and some of their boilers were used in other locomotives because they were made of an unproblematic alloy. The Reichsbahn was not so lucky, and so the available locomotives had to be made ready for a longer service life. In many cases, some formerly simplified assemblies were exchanged for more modern ones. Also, some welded fireboxes were installed instead of the previous riveted ones, especially since expensive non-ferrous metals had been replaced with steel in some places on the war locomotives. The Reko program of the Reichsbahn also included 200 units of the class 52, which were now designated as 52⁸⁰ and, among other things, received the same boilers as the 50³⁵. With around 2,000 hp, these were considerably more powerful than the original models. Another 25 units had been converted to pulverized lignite as the class 52⁹⁰. The last pieces of the reconstructed locomotives were in scheduled use until 1988.

Since the procurement of new diesel locomotives and the electrification did not progress as hoped, the Reichsbahn was still dependent on the freight locomotives of the class 52. However, as war locomotives, these were greatly simplified compared to the class 50 and, due to the lower production quality, were already in a condition by the late 1950s that did not allow further use for several years.

So in 1959, as part of a general overhaul, the “Entfeinerungen” (“de-refinements”) were removed and the firebox and the steering rack of the leading axle were replaced in particular. They also received a mixing preheater. Although it was believed that these locomotives would no longer be needed in some years, the measure did not bring the expected success. So another measure had to be found to increase the service life of the locomotives.

Thus, in 1960, the RAW Stendal began with a complete rebuild, which resulted in the class 52⁸⁰. It was a fundamental rebuild in which hardly any assembly was left untouched. Only locomotives with a plate frame were selected for the rebuild. The heart of the measures was the new boiler with a combustion chamber, which had been developed for the class 50³⁵. Some improvements were also made to the chassis and the tenders were rebuilt. The chimneys were partially replaced by Giesl ejectors. 

52 8075 in December 2006 in Eisenach

HeizDampf, User:Sandmann4u

Contrary to the expectations of the Reichsbahn, the class 52⁸⁰ had to hold out for several more decades. Over time, not replacing the 52's simplified slide valves proved to be a mistake. These led to worse behavior when idling and it was only in the 1980s that they were replaced with better ones on some locomotives in RAW Meiningen. The service time of the last 52⁸⁰ ended in 1990 and until 1994 some were used as heating locomotives.