The express locomotives of the class 01 were the first standard locomotives that the Reichsbahn purchased from 1925. These were Pacific locomotives with a two-cylinder engine. In contrast to the sister class 03, which was developed later, it had an axle load of 20 tonnes, which a high power possible, but limited the area of application to the few routes that had already been upgraded at the time. Before series production began, a comparison was made with the otherwise almost identical class 02 with a four-cylinder compound engine, which the 01 was able to claim for itself.

The features that all standard locomotives later had in common could be observed for the first time. In part, modern advances in steam locomotive design were ignored to allow for a simpler, standardized design. These included the abandonment of a combustion chamber and using two- and three-cylinder engines with simple steam expansion instead of compound engines. Due to the long boiler without a combustion chamber, the pipes were 6,800 mm long, which led to stresses in the material under heavy loads. These problems were also encountered with other large standard locomotives and they were only solved after the war when new boilers with a combustion chamber and thus shorter pipes were installed.

At the front, the large Wagner smoke deflectors and skirts were used, which led to a characteristic appearance. The top speed was initially 120 km/h, but was increased from 01 102 to 130 km/h by increasing the diameter of the front wheels from 850 to 1,000 mm and strengthening the brakes. The first series used the shorter 2'2 T 30 with ten tonnes of coal and 30 cubic meters of water as a tender. Later the 2'2 T 32 was used with the same amount of coal and 32 cubic meters of water and over the years many machines were given the 2'2 T 34 from the class 44.

Series production in larger numbers did not begin until 1930, but a total of 231 machines were built by 1938 and another ten were created from the conversion of the test locomotives of the class 02. After the war, the 01 remained a very important flagship for express trains for both German railway administrations for a long time. However, their condition made some modifications necessary, which were carried out on both sides. At the Bundesbahn they mainly received welded boilers with a combustion chamber, and at the Reichsbahn the changes were much more extensive. The resulting class 01⁵ will be described in a separate article. The latter remained in use until 1982, while the decommissioning in the Bundesbahn was completed in 1973.

In order to develop a new express locomotive for speeds of up to 150 km/h, the design of the proven class 01 was used. These were already designed for 140 km/h and now they wanted to increase the usable speed range by means of a streamlined fairing. The fairing encompassed the entire locomotive, including the tender, and reached down to 400 mm above the railheads. Only on the coupling wheels was there a cut-out, e.g. to make it easier to lubricate the drive and coupling rods. The fairing had no effect at low speeds, but at over 120 km/h the drawbar power could be significantly increased.

Since the running smoothness of the original two-cylinder engine of the 01 left a lot to be desired even at its top speed, an engine with three cylinders was used for the 01¹⁰. Since the original engine was designed for only two cylinders, it was not entirely possible to ensure optimal steam distribution between the three cylinders. Although the locomotives thus achieved a lower indicated power than the 01, the advantages were the smoother running and the cladding. Instead of the initially required 550 tonnes of towing capacity at 120 km/h on the level, in reality they reached up to 660 tonnes at this speed.

In 1939 it was assumed that more than 400 locomotives would be required and initially a total of 204 units were ordered from several factories. Due to the outbreak of war, only 55 01¹⁰ were built. In everyday use, it became apparent that the streamlined fairing only had a positive effect at the rarely achieved high speeds, and it was also an obstacle to maintenance. Over time, the fairing was completely or partially removed from many locomotives.

After the war, all remaining pieces came to the Bundesbahn. They were mostly in very bad condition and were to be be retired, but due to the lack of locomotives they were rebuilt. All parts of the cladding were removed and boilers made of the problematic steel alloy St 47 K were replaced with new welded ones with a combustion chamber. The indicated power now reached 2,350 hp, and even 2,470 hp for oil-fired engines.

When the Bundesbahn switched to the computer numbering system in 1968, they renumbered the coal-fired units as class 011 and the oil-fired units as class 012. They remained indispensable until the electrification of the last main lines was completed and were retired by May 31, 1975.

As already described for the 01, when the first standard express locomotive was being constructed, it was not yet certain which type of engine would be the best. Thus the 02 was created as an alternative to the 01 in order to be able to compare different designs. While the 01 featured a simple two-cylinder engine, the 02 was powered by four compound cylinders. The 02 was operational even before the 01 and was therefore the Reichsbahn's first standard steam locomotive. With it, the use of bar frames at the Reichsbahn began, with which the Bavarian State Railways had already made good experiences.

Henschel works photo

Die Lokomotive, February 1926

Except for the engine, the two classes were almost identical in order to create the optimal conditions for a comparison. Instead of the two cylinders with a diameter of 600 mm each on the 01, the 02 got two cylinders each with a diameter of 720 and 460 mm. Due to the tendency of this engine to run more smoothly, they were approved for 130 km/h from the start, which was only the case with their sister after modifications.

Schematic drawing with dimensions

Locomotive Magazine, January 1931

In 1925 and 1926, ten of each variant were built, which were then compared in day-to-day operations at the Erfurt, Hamm and Hof divisions. As expected, the 02 was smoother at higher speeds and slightly more powerful. At cruising speed, consumption was lower than that of the simple engine, but contrary to expectations it was higher at lower speeds.

However, some experts argue that the steam paths of the two locomotives were designed in a way that their characteristics were more favorable for two-cylinder engines. Ultimately, it was concluded that the 01, with its two cylinders, was the better choice for series production. Today it is known that Wagner, who was head of the design department at the time, had a personal dislike for compound steam locomotives and, in his opinion, the more difficult maintenance negated the advantages of lower consumption. With a different design of the steam engine, significantly better power could probably have been achieved, after which the disadvantages of the four cylinders could have been accepted.

Despite the lack of series production, the ten units of the class 02 were still used. However, since they were identical in construction to the 01 except for the engine, all of them were also rebuilt to two cylinders between 1937 and 1942. Up to this point, the locomotives had been in use in the Hof area, where the tests had also taken place. So after the war they remained on the territory of the Bundesbahn and no distinction was made to the actual 01 in operation. The last to be retired was 01 234, former 02 003, on May 8, 1972.

In the 1920s, Stephan Löffler developed the basics for a steam locomotive boiler at the TH Berlin-Charlottenburg that worked at a pressure of 120 bars (1,740 psi). The BMAG took advantage of this and built the H 02 1001 for the Reichsbahn in 1930. It was hoped that a coal saving of 42 percent would be achieved. It used the chassis of a class 01 locomotive, but was classified into class 02 due to the compound engine. 

The H 02 1001 had a firebox made of parallel tubes. The two outside high-pressure cylinders had a diameter of only 220 mm and were fed by steam that had passed through a three-stage superheater. Before the steam was fed into the inner low-pressure cylinder with a diameter of 600 mm, it passed through another reheater and so still had a pressure of 13 or 14 bars.

However, various problems arose again and again during the trials. These included burst superheater tubes or leaks in the high-pressure cylinders. In reality, only about 20 percent of coal was saved, which did not justify the complicated design and the many problems. The locomotive was therefore returned to the BMAG in 1934. After sitting there unused for eleven years, it was scrapped.

With its 20-tonne axle load, the class 01 could not be used on many routes. Although the plans provided for the upgrading of all main routes for these loads, this project could not be implemented due to the economic crisis, and it could not have been completed within a few years. Thus, the class 03 was developed, which was almost identical in construction to the 01, but lighter.

The main changes consisted in the fact that the bar frame was now only 90 mm thick instead of 100 mm, the diameter of the cylinders was reduced from 650 to 600 mm and the pressure of the slightly smaller boiler was reduced to 14 bar. With almost identical external dimensions, an axle load of 17.7 and later 18.1 tonnes was achieved, thus significantly expanding the range of routes that could be used. After the first three examples, the boiler pressure was increased to 16 bar, analogous to most standard locomotives, but in return the diameter of the cylinders was further reduced to 570 mm.

03 001 in the year 2000 on the turntable in Dresden-Altstadt

Olaf1541

As with the 01, the top speed was initially 120 km/h and later from the 03 163 130 km/h after the diameter of the leading wheels had been increased. Since the series was even designed for 140 km/h, some examples could also be approved for this speed after adapting the braking equipment. With a few engines, the performance in the high speed ranges could be significantly improved by using a complete or partial streamlined fairing, but this was later removed again, as was the case with the development 03¹⁰. The series machines could pull trains of 430 tonnes at 120 km/h and 790 tonnes at 100 km/h on the flat.

The three coupled axles were fixed in the frame and only the middle driven axle had wheel flanges that were 15 mm weaker. The front bogie could be moved sideways by 100 mm, the trailing axle behind the firebox was an Adams axle and had 140 mm of play. As with its heavier sister, the wheels of the bogie were 850 or 1,000 mm depending on the year of manufacture, the coupled wheels were 2,000 mm and the wheels of the trailing axle were 1,250 mm.

With a total of 298 locomotives built between 1930 and 1938, the 03 reached a larger number than the 01. After the Second World War, the West German Federal Railways received 154, the East German Reichsbahn 86 and the Polish PKP around 40 units. In the case of the latter, the engines were called Pm 2. In 1968, only 45 units were still in use on the Bundesbahn, all of which were in storage by 1972. The Reichsbahn equipped damaged locomotives with a welded firebox and feedwater heaters. The larger part of 55 engines was even completely reconstructed and provided with completely welded new boilers between 1969 and 1975. Due to the combustion chamber, they only had 5,700 mm long heating pipes instead of the 6,800 mm of the original boilers, which was already in the problematic area. They had an output increased by around 100 kW and were still used in the 1980s.

In addition to the class 01, the 03 was also taken on in order to develop a variant with streamlined fairing and three cylinders. The result was the class 03¹⁰, which was designed for 150 km/h and was only certified for 140 from 1940. Instead of the 140 units ordered, only 60 were finally completed, as production had been focused on freight locomotives since the outbreak of war. In the case of locomotives supplied by Borsig and Krauss-Maffei, the fairing was pulled over the entire drive train and running gear to just above the upper edge of the rails, while Krupp left a cutout in the area of the coupled axles just above the axles. Since the original locomotive was only designed for two cylinders, the steam of the 03¹⁰ could not be optimally distributed between the three cylinders and the indicated power fell by almost 200 hp compared to the 03.

Although streamlined locomotives had about 50% less drag, the fairing not only restricted accessibility for maintenance, but also limited engine cooling. As early as 1942, the fairing was gradually removed from the fully encased locomotives up to the top of the coupled wheels. For the time being, the Krupp locomotives continued to run with their incised fairings. After the war, traffic on both sides of the Iron Curtain was initially not possible at the speeds at which streamlining offered advantages over conventional locomotives. Since these were also often in very poor condition, they were completely removed from all locomotives. From now on, a striking feature of these engines was the slanted top smoke box, but some conversions also included a new smoke box with a round door.

In the case of the 26 locomotives of the Bundesbahn, the later conversions were mainly limited to replacing the non-ageing St 47 K boilers with new ones made of a more durable alloy. Although the new boilers had a combustion chamber, the output was only slightly higher than before. They were retired between the end of 1965 and the end of 1966 and finally scrapped without exception.

03 1010 without fairing in 2002

Olaf1541

Since the shortage of locomotives at the Reichsbahn was more serious, 16 of the 17 units of the 03¹⁰ were included in the reconstruction program. The most modern construction principles were used in the subsequent fundamental rebuilding in order to be able to use the locomotives for a few more years in front of the highest-quality express trains. In the period when their sisters were already being phased out by the Bundesbahn, almost all engines in the GDR were given oil firing. Especially with the latter, a significant increase in performance was possible, some claims of 2,350 hp are given. After some of the reconstructed engines had achieved monthly mileages of more than 20,000 km, they were retired by 1980.

In order to increase the power of the standard locomotives while at the same time reducing the specific consumption, two medium-pressure test locomotives were built on the basis of the class 03 and designated as class 04. The aim was to run production locomotives with a boiler pressure of 25 instead of 16 bars in the future. The most important change to implement the plans was the use of high-strength steel alloys in the two examples built. The 04 001 was equipped with a boiler made of copper-manganese steel, while the 04 002 got one made of chrome-molybdenum steel. In addition, a compound engine with four cylinders was chosen in order to be able to better utilize the higher steam pressure.

First test runs showed that the power increased from 1,980 hp on the 03 to around 2,320 hp. At the same time, the specific consumption of steam and coal fell significantly, although the 03 was also considered to be very economical. The specific steam consumption was reduced from 6.3 to 5.2 kg per hp hour, while the specific coal consumption based on the drawbar power fell from 1.13 to 0.96 kg per hp hour. Although the boiler itself was able to withstand the higher loads, leaks soon became apparent in the area of the firebox at the seams and stay bolts. Attempts were subsequently made to get this under control by means of rebuilds, but this was unsuccessful. As a result, the boiler pressure was initially reduced to 20 bars and later even to 16 bars.

04 001 in 1932

Werner Hubert / Eisenbahnstiftung - Bildarchiv

The two locomotives were now structurally very similar to the prototypes of the somewhat heavier class 02, which is why they were used as 02 101 and 02 102 from now on. With only 2,100 hp, they no longer had any major advantages compared to the 03, which was easier to maintain. The use of other production locomotives from other classes with 20 bars was not convincing either, since the stronger steel alloys showed much more signs of aging than the conventional steels. In the end, all standard locomotives continued to be operated with a boiler pressure of 16 bars. The outbreak of war prevented further promising developments in terms of boiler pressure. There were only isolated attempts with extremely high pressures, but these were also unsuccessful.

In addition to the tank locomotives of the class 61, the need for more powerful express locomotives was also recognized in order to be able to transport regular, heavier express trains at higher speeds. A tender followed among various companies, the winner of which was a streamlined 4-6-4 locomotive from Borsig. In contrast to its competitors, some of which were also designed as steam turbine locomotives, the class 05 was created as a conventional three-cylinder steam locomotive, which was based as far as possible on the design of the standard locomotives. In 1935 road numbers 05 001 and 05 002 were built in the regular design, followed in 1937 by the different 05 003.

The locomotives had coupling wheels measuring 2,300 mm and a two-axle bogie at the front and rear. The streamlining completely covered the running gear, it had a straight lower edge and went down to a few centimeters above the rail heads. The five-axle 2'3 T37 tender was also paneled, but otherwise mostly compatible with the standard design. The tender's paneling was flush with the locomotive's paneling, removable, and closed off the cab at the rear.

Test drives showed an indicated power of around 2,360 hp, but significantly more was possible for a short time. The regular maximum speed was 150 km/h, and 175 km/h was approved to make up for delays. A typical train mass for these speeds was given as 250 tonnes.

Calculations had shown that at 140 km/h a performance increase of 385 hp at the towing hook had been achieved through the fairing. As with all large standard locomotives, the problem was the large length of the heating pipes, which here reached 7,000 mm and tended to lead to tension. In contrast to most other locomotives of this time, the coupling wheels were braked on both sides and, in addition, a speed-dependent control of the brake was achieved by means of a centrifugal governor. This allowed the usual train weight to come to a standstill at a distance of 1,200 meters from the distant signal within a defined time.

During the test drives and in the subsequent scheduled use of the first two engines, they often exceeded the requirements. The rule were trains consisting of five heavy express cars and together weighing almost 250 tonnes. In the process, speeds were kept above the permitted maximum speed over longer distances on several occasions. On May 11, 1935, road number 05 002 drove between Hamburg and Berlin with only four cars. Although no record run was planned, the speedometer needle reached its stop at 200 km/h and stayed there for a long time. Using the milestones and time measurements, an average of 200.4 km/h was calculated over 5 km and 201 km/h for a short time.

In addition to a calculated output of 3,400 hp, this meant a speed record for steam locomotives, which is still disputed today. The record is often attributed to the English “Mallard” with 201.2 km/h, but not only did this trip take place on a slight downward gradient, it also resulted in damage from an overheated bearing on the connecting rods and it is usually claimed that the trip was not adequately documented. Some American locomotives also allegedly reached over 220 km/h, but in these cases there is no reliable documentation.

The third locomotive followed in a very unusual configuration, since at these speeds there were advantages in moving the driver's cab forward. In order to avoid separating the fireman and driver, the boiler was installed backwards. Since the firebox was now on the opposite side of the tender, pulverized coal firing was installed. The coal dust was transported through a pipe that ran through the entire frame and also had bends due to the inner cylinder. Another difference was the installation of a combustion chamber to allow the gases, which were very hot after the rapid combustion, to cool down a little before hitting the heating tubes. The design of 05 003 did not work, as there was a lack of combustion air in many situations and there were frequent blockages due to slag deposits. Finally in 1944, the boiler was rotated to the conventional position and converted to fire regular coal while the cladding was removed.

In contrast to almost all locomotives available in small numbers, the German Federal Railroad did not decommission the three 05s because they could not do without these fast and more powerful engines. During the rebuild in 1950, the remnants of the paneling, which had already been damaged during the war, were also removed from 05 001 and 002. This did not result in any noticeable disadvantages because the network no longer allowed the highest speeds. However, the boiler pressure was reduced from 20 to 16 bars to reduce the wear.

In 1957 and 1958, the three units were replaced by class V 200 diesel locomotives. Road numbers 002 and 003 were then scrapped by 1960, with only the 001 remaining. The paneling of the latter was then largely restored and the locomotive was taken to the Nuremberg Transport Museum.

For particularly heavy express trains on mountainous routes, two prototypes of the class 06 were built in 1939 as the only German steam locomotive with a 4-8-4 wheel arrangement. They got the boiler of the class 45 and streamlined cladding. As with the 45, the boiler with the overly long tubes caused problems. There were also occasional derailments in narrow switches. Due to the Second World War, there was no series production and after the end of the war, no revised machines were built due to a lack of demand.

This high-pressure locomotive was created on the initiative of the director of the Schmidt superheater company from a Prussian S 10² that the Reichsbahn had made available for this purpose. The firebox was traversed by pipes in which distilled water circulated at 90 bars. The high-pressure cylinder was operated at 60 bars and the low-pressure cylinder received 14 bars. Since the expense of this conversion was not worth it compared to the extra power, the locomotive was restored to its original condition in 1929.