After the 0-8-0 wheel arrangement had established itself with the class 33 and 34 locomotives at the Semmering, the class 35a was created in 1871. Under the direction of Louis Adolf Gölsdorf, a new locomotive was created that, unlike its predecessors, had an inside frame and outside controls.

Since an axle load of 13 tonnes was now permitted, a significant increase in power was possible. With a length of 2,300 mm, the firebox achieved the best value for its time. Because it was completely behind the last axle and this could be moved sideways by 20 mm, there was a large overhanging mass. With a top speed of 35 km/h, however, this was of little consequence.

Production comprised 25 machines from Wiener Neustadt, 25 from the StEG workshops and five from Floridsdorf in 1871 and 1872. After the Upper Italian SFAI had loaned a locomotive for testing, 60 almost identical locomotives were ordered in Wiener Neustadt. These led to the later FS class 420, which was built by other manufacturers until 1905.

The locomotives of the class 35a were able to pull 210 tonnes on a ramp with a gradient of 2.5 percent. In addition to the Semmering Railway, they were also used on the Brenner Railway and in the Karst Plateau of present-day Slovenia. Like their predecessors, they were later given Kobel chimneys.

After the Second World War, 20 examples came to the FS and became class 452 there. 23 units came to the Kingdom of the Serbs, Croats and Slovenes, of which 16 were later taken over by the JDŽ as class 132. The twelve locomotives remaining in Austria became the class 471 of the BBÖ. The three locomotives remaining in 1938 were classified by the Reichsbahn as 55 5601 to 5603.

After the class 35a, the Südbahn had ten other very similar locomotives built by Sigl in Wiener Neustadt. Since the 35a was said to have a boiler “overflowing” with tubes, the 35c received fewer heating tubes. The tube heating area fell from 159 to 138 square meters, while the grate area remained unchanged and the area of the firebox hardly changed. In addition, they were fitted with a Le-Chatelier-Ricour countersteam brake.

After the First World War, two came to the Italian State Railways, where they became Gruppo 454. The rest all came first to the state of Serbs, Croats and Slovenes and were later classified by the JDŽ, just like their predecessors, in the class 132. Thus, the BBÖ did not receive any members of this class at all.

In 1873, the Kaiserin-Elisabeth-Bahn initially received eight freight locomotives from the Sächsische Maschinenfabrik Hartmann in Chemnitz. One of them received an honorary diploma at the 1873 World Exhibition in Vienna. The next 16 locomotives came from Austria, namely from Wiener Neustadt and Floridsdorf.

These were eight-coupled locomotives with a wheel diameter of 1,106 mm for use on low mountain lines with a low axle load. To run through tighter curves, the fourth axle could be moved laterally by 20 mm. They had outside cylinders but inside valve gear.

When the KEB was nationalized in 1884 they became the kkStB class 70. Shortly thereafter they received new boilers to extend their life. After the First World War, a total of five came to the ČSD, which remained in service for more than 20 years. The two machines of the BBÖ were retired in 1936.

Over a long period from 1866 to 1891, the Nord had a total of 430 freight locomotives of basically the same type built. With the 0-8-0 wheel arrangement, they were among the most powerful models at the time of their introduction. The nickname “180 Unités” came from a French unit to measure tractive forces. Four units corresponded here, for example, to a freight car with a load of less than ten tonnes, which is pulled on the flat at 50 km/h.

The cylinders, which were quite large with a diameter of 500 mm, were already mounted outside the frame. In reality, the locomotives could pull coal trains weighing 680 tonnes on lines with a maximum gradient of 0.6 percent. At 1.2 percent, 415 tonnes could still be pulled. In later series, the boiler pressure was increased from 8.5 to 10 bars, which increased the train weights accordingly.

The locomotives built after 1879 were fitted with a boiler with a Belpaire firebox. From 1890, a driver's cab was installed ex works. Between 1907 and 1913, 108 locomotives were rebuilt into tank locomotives. Other machines from the Nord-Belge that were almost identical in construction were also rebuilt in this way and used in Belgium.

When the SNCF was founded in 1938, only two of the non-rebuilt tender locomotives were still in use. Of the 108 tank locomotives, a total of 104 were still in use. The last of these remained in use as shunting locomotives until 1962. Today only 4.853 survives, which was not converted into a tank locomotive and was used in a sugar refinery until the 1960s.

To haul heavy coal trains from Peterborough to London, Ivatt developed the class K, which was soon dubbed the “Long Tom” because of its longer boiler compared to the six-coupled locomotives. The dimensions of this boiler roughly corresponded to the class 990 or C1 (small boiler) Atlantics. It could generate enough power to haul 60 full wagons of coal. This corresponded to a train weight of 1,052 tons compared to 681 tons for the older, six-coupled freight locomotives. With the cylinder dimensions required for this, it was still possible to arrange the cylinders within the frame. From 1901 a total of 55 engines were built.

Although the engines could handle the required train weights without any problems, a high coal consumption was noticeable. Therefore, from 1908 almost all engines were superheated, with two different variants being created. The first one, later designated by the LNER as the Q1s class, retained the original cylinder dimensions and slide valves. The others, which later became LNER class Q2, used cylinders with a diameter of 21 instead of 20 inches and piston valves instead of slide valves. Both variants had Schmidt-type superheaters and both had the fully automatic Klinger-type lubrication required for superheated operation.

In 1913 number 445 was fitted with the Doncaster superheater developed by Gresley. No other engines with this superheater followed. From 1923, it was listed as class Q3 by the LNER due to its different power characteristics. In 1914, number 420 was fitted with a significantly larger boiler. Since the other boilers of this type were finally used for the 2-6-0 machines of class K2, the 420 remained a one-off.

In the 1920's the superheaters were replaced with the Robinson type which were standard on the LNER. With the introduction of the 2-8-0 locomotives of classes O1 and O2, the locomotives were no longer needed for transporting coal to London and were increasingly used in more northerly areas. During this time they were nicknamed “Sea Pigs” because of their high water consumption compared to other locomotives. From 1926 the retirement began, whereby the few locomotives with saturated boilers were affected first. By 1935 all Q1s and Q2s were gone and the only Q3 lasted until 1937.

The railway administrations of the Tsarist Empire combined eight-coupled freight locomotives under the letter О, which made it to a number of more than 9,000 in different versions. The series went back to a type from Maschinenfabrik Esslingen, which had been supplied to several railway administrations from 1878 onwards. In order to follow the trend of the time, the Vladikavkaz railway had two-cylinder compound locomotives based on this type manufactured in Kolomna in 1890, which marked the beginning of the О series.

From 1893 a unified standard type was manufactured, which had a wheel diameter of only 1,150 mm and cylinders with a diameter of initially 500 and 710 mm with a stroke of 650 mm. After 129 examples were produced, the diameter of the low-pressure cylinder was increased to 730 mm. A total of 1,373 examples of the standard type from 1893 were manufactured by 1899, which were also supplied from Germany and Austria due to the limited capacities of the Russian factories.

In 1897 a new standard type appeared, of which a total of 3,172 were built by eight Russian factories by 1903. This variant, designated О^д, now had a driver diameter of 1,200 mm and a boiler pressure increased from 11 to 11.5 bar.

After two prototypes were completed in 1899 with Heusinger-Walschaerts type valve gear instead of the problematic Joy valve gear, a total of 4,178 examples were built between 1901 and 1907, which also had Heusinger-Walschaerts valve gear. The diameter of the cylinders had been increased to 510 and 740 mm. The two types were designated О^в and О^k and were alternatively known as the 1901 standard type and the 1904 standard type. Between 1908 and 1915 another 190 examples of the О^в were made.

When superheated steam became established in locomotive construction, a few locomotives with superheaters and simple expansion were built between 1908 and 1915. These were given the designation О^п and soon other examples of the earlier series were rebuilt in the same way. After the October Revolution, another 72 were made between 1925 and 1928. Later, some locomotives received boilers with a pressure of 14 bar during rebuilds. After the introduction of more powerful freight locomotives from the 1930s, they were increasingly used for shunting. The last operations on the route took place in 1964 on a branch line of the Trans-Baikal.

Number 6 of the k.u.k. Feldbahn (Imperial and Royal Field Railway) was one of five prototypes from different manufacturers which were tested at the beginning of the 20^th century. It was built by MÁVAG of Budapest in 1902 and was the only one of the five that had an additional tender. The first of four driving axles was a Klien-Lindner axle that could be adjusted radially. The second and third axles were special in that they had outside wheel flanges, which caused problems when running over switches. In the end, this locomotive type was not produced in series and the prototype came to the Beszterce forest railway in 1918.

After the four class 76 freight locomotives had been put into service on the Arlberg in 1884, the class 73 shown here was introduced only one year later. The new locomotive was also a 0-8-0, but had smaller cylinders and produced around 700 hp. As the first batches were built for the Arlberg Railway, they were just called “Arlberg type”. Soon they were also built for the Galician Transversal Railway and many other lines.

Between 1885 and 1909, a total of 454 were delivered by several manufacturers. On the flat, they could haul 1,650 tonnes at 30 km/h. A speed of 15 km/h could be attained either with 580 tonnes at a one percent grade or with 220 tonnes at 2.5 percent. When faster and more powerful 2-8-0 and 0-10-0 locomotives were introduced, the class 73 was increasingly used for shunting service.

After World War I, only 44 stayed with the BBÖ. 233 locomotives, more than a half of the original production, came to Poland and became PKP Tp15. 119 became class 414.0 of the ČSD, 25 came to Italy, 17 to Romania and four to the future Yugoslavia. In 1938, the Austrian locomotives became Reichsbahn class 55⁵⁷. After the war, 38 were used by the ÖBB as class 55 until 1964. The ČSD retired the last one in 1969. 414.096 was preserved and is operational again since 2019.