Towards the end of the 1930s, the Reichsbahn saw a need for a new passenger locomotive, which led to the development of the class 23 with the wheel arrangement 2-6-2. It was primarily intended to replace the Prussian P 8. Since the war that had just begun saw only a need for freight locomotives and passenger traffic was severely neglected, only two examples were built. After the war, however, these served as a model for a new variant in both parts of Germany, of which just over 100 were to be built.

After experience had already been gained at the beginning of the century in Prussia with the classes P 8 and G 10 of producing a passenger and freight locomotive with the same boiler, this principle was also applied here. Around the same time, the class 50 freight locomotive was built with a 2-10-0 wheel arrangement. Thus, the same boiler was used for both. In the development of the class 23, as with the 50, some new developments were dispensed with, which would have increased the possible boiler load by heating surface. As a result, however, the number of identical parts with earlier standard locomotives remained higher and production could also be carried out more cheaply. An improvement compared to older locomotives was a front wall on the tender. This fulfilled the same function as a closed cab and protected the crew when reversing.

Both examples came to the Reichsbahn of the GDR after the Second World War. In 1961, road number 23 001 received a modern, welded boiler with a combustion chamber, as was used on the Rekoloks. The second one was not rebuilt because its wheels and frame were damaged and was therefore retired in 1967. The remaining locomotive was renumbered 35 2001 in 1970 to distinguish it from the newly built post-war locos.

As already mentioned, further developments of the original 23 were made on both sides of the inner-German border after the war. The class 23¹⁰ of the DR kept almost completely to the dimensions of the prototype, but benefited from modern technical achievements and contemporary manufacturing methods. Between 1955 and 1959, 113 were made at the LKM Babelsberg. In contrast, the class 23 of the DB was based on BMAG's unimplemented plans for the alternative design of the 23. 105 of this variant were built between 1950 and 1959.

After the war, both German railways developed a new steam locomotive from the prototypes of the advanced class 23 from 1941 in order to supplement their fleets, which had been decimated by the war, and to be able to replace the Prussian P 8 in the long term. While the variant of the Reichsbahn was first designated as the class 23¹⁰ and later as the class 035, the Bundesbahn variant was only given the designation 23.

Like its Eastern counterpart, modern technologies were used, such as a boiler with a combustion chamber, and most importantly, welding technology was widely used. Much attention was also paid to the chassis. The resulting locomotive showed a significantly increased power compared to the P 8 and immediately proved itself in use. It was one of the few locomotives with a tender that could also run backwards at maximum speed, even if this was limited to 85 km/h for safety reasons and the full 110 km/h was only permitted forwards. In addition, with this class, great importance was attached to the working conditions of the crew, which made it one of the few German steam locomotives with a completely enclosed driver's cab. Previously the cabs were open at the back and partly on the sides, but in the class 23 there was a heated floor, a locker for clothes and even a possibility to heat food. In addition, 16 of the total of 105 examples were given push-pull train control for more efficient use in passenger transport with the control cars, which were still new at the time.

In spite of all these advantages, the end of the steam age was slowly approaching, and thus the class 23 did not survive the P 8 to be replaced by very many years. So it happened that the last P 8 was decommissioned by the Bundesbahn in 1974 for reasons of age, but the last 23 was also turned off in 1975 due to the changeover to the new types of traction.

The kkStB network included many routes on which both passenger and express trains could not travel faster than 70 or 75 km/h due to the topographical conditions. When the four-coupled engines were no longer sufficient for these services, it was necessary to switch to a six-coupled engine. At that time, the 4-6-0 wheel arrangement was popular in other countries, but it didn't offer much space for a large firebox between the coupled wheels. Since a trailing axle was needed due to the low-energy coal in Austria, the class 110 for faster trains had been introduced as early as 1905 with a 2-6-2 wheel arrangement. So Gölsdorf also developed the class 329 with this wheel arrangement, but a driver diameter of only 1,614 mm.

The running gear was taken over almost unchanged from the tank locomotive of the class 229. This had a two-cylinder compound engine and had already been introduced in 1904 for passenger trains. Since the water and coal reserves on the locomotive were no longer available, a significantly larger boiler could be used. This was placed high in order to be able to arrange an even larger firebox above the last coupled axle and the trailing axle. Instead of a Schmidt superheater, a Clench-Gölsdorf type steam dryer was used.

Schematic drawing with dimensions

Die Lokomotive, June 1907

The kkStB had 93 pieces built, which came from all the important factories in Austria. Although they reached up to 110 km/h in test drives, they were approved for 80 km/h. A speed of between 42 and 45 km/h was reached with a train load of 313 tonnes on a one percent steep, winding incline, which corresponds to an output of 950 to 1,000 hp. Alternatively, express freight trains of up to 750 tons and conventional freight trains of up to 1,150 tonnes could be transported on gentle gradients.

In addition to the kkStB, the k.u.k. Military railway Banjaluka-Dobrlin bought two pieces and the MÁV a total of 65 pieces. Although MÁV had its own factory, all engines were built in the same factories that kkStB engines came from. The Hungarian engines had the Westinghouse air brakes, while the Austrian had a vacuum brake.

After the First World War only 20 locomotives ended up with the BBÖ. The PKP had received 21 pieces and called them Ol11. After the Second World War, the PKP received another 14 of the BBÖ locomotives, which the Reichsbahn had relocated to Kraków as class 35¹ and were therefore in Poland after the end of the war. A total of 38 units came to Czechoslovakia to the CSD, which classified them as class 354.1. They were gradually all converted into superheated steam simples and were also given electric lighting and air brakes. The last of them were in service until 1968.

The class 429 passenger locomotive of the kkStB was introduced in 1909 after superheater technology had established itself in Austria. It was developed from the 2-6-2 class 329 and looked very similar to that. The smokebox had been extended at the cost of the boiler tubes to create enough space for the superheater header.

The first 57 locomotives, numbered in the 429.01 range, had slide valves which led to some problems while running on superheated steam. So another 126, numbered from 429.100, were built with piston valves. Also the Südbahn ordered six of this Type. While these were all two-cylinder compounds, a two-cylinder simple variant was built as 429.900. These reached the highest number with 197 built until 1918.

They quickly became spread over all Austria-Hungary. After the war, a large number came to several countries. So they became ČSD class 354.7, FS class 688, JDŽ class 106, PKP class Ol12 and MÁV class 323.9. The ČSD also rebuilt all their 84 compounds into simples, what made 152 together with the original 429.9. Most got two domes with an interconnecting pipe and were used until 1967.

For fast mixed traffic, Gresley took his A1 and A3 Pacifics, shortened the boiler, switched the two-axle leading bogie for a single axle and fitted smaller 6 ft 2 in (1,880 mm) driving wheels. So they still had three cylinders, which were cast in a single piece. The LNER designated these locomotives class V2, while the first one numbered 4771 was named “Green Arrow” after a prominent express goods service.

They became the only successful British 2-6-2 tender locomotives and were not much slower than the Pacifics. Although their axle load of 22 tons limited their area of operation, their most suitable roles were the service with fast goods trains and very heavy expresses. In service they sometimes reached speeds of 90 mph, while one locomotive was even credited to have exceeded 100 mph on a test run.

Between 1936 and 1944, a total of 184 were built in Doncaster and Darlington. They fulfilled very important duties in World War II, but due to the reduced track maintenance the leading bogie had to be replaced by a new one. After less successful experiments with double chimneys in 1960, eight got a Kylchap exhaust. These had performances on par with the Pacifics and were thus called “Super V2”.

However, Thompson's 4-6-0 class B1 had superseded the V2 in mixed traffic and became the new LNER standard locomotive in this role. The V2 were withdrawn between 1962 and 1966. 4771 “Green Arrow” is the only one that was preserved. It was operational until 2008 and is still waiting for a boiler overhaul.

The last four steam engines the McCloud River Railroad purchased in 1925 were oil-fired and made by ALCO. The numbers 20 and 21 from 1924 already had the wheel arrangement 2-6-2 and came from Baldwin. Then numbers 22 and 23 with the same wheel arrangement came from ALCO. The numbers 24 and 25, which were again delivered in the same year, had two inches larger coupling wheels and larger cylinders to compensate.

They were in service with logging operations until the mid-1950s, when steam operations ended at the McCloud. The number 25 was reactivated in 1962 for special trips. After operating on its original route with some interruptions until 2001, it joined the Oregon Coast Scenic Railroad in 2011 and is still in service today.

Cecil Paget, the superintendent of the Midland Railway, had a steam motor locomotive built to his own design in 1908. It had eight uniflow cylinders located between the axles and controlled by a rotating shaft. They drove jackshafts, which in turn acted on three axles. The boiler was also special, having a large diameter and a firebox similar to the Wootten fireboxes used in the United States.

The financing of the locomotive was supposed to come entirely from Paget's private funds, but when these were not sufficient the Midland Railway had to intervene. Although the locomotive was tested on public lines, its existence was kept secret from the public. This was probably also due to the fact that Richard Deeley, locomotive superintendent at the time, did not believe in the success of the locomotive.

During testing, problems arose regularly, which mainly affected the valve gear. The locomotive was stored since 1912 and was no longer tested. It was apparently scrapped in 1918 in Paget's absence when he was in charge of the Railway Operating Division in France. The only known photograph appeared only after the 1923 grouping.