As a successor to the class 4 and 5 express locomotives, Karl Gölsdorf developed the class 6, which was his first express locomotive. Like its predecessors, it also had two coupled and running axles each. In order to achieve the required increase in output, Gölsdorf took a different approach to arranging the boiler, which was inspired by the famous number 999 of the Pennsylvania Railroad, among others.

Instead of arranging the boiler very low, as was previously the case, to achieve the smoothest possible running, a boiler with a larger diameter was used here, with the firebox standing completely above the frame. Thus, a continuous output of up to 900 hp could be achieved through a larger grate and evaporation surface. In addition, a two-cylinder compound engine with the high-pressure cylinder on the right side was used.

A total of 68 examples were built between 1894 and 1898, which reached speeds of up to 130 km/h in test drives. Nevertheless, the certification was only granted for a speed of 90 km/h, which was sufficient in Austria. The BBÖ still had 20 units in service after the First World War and used them until 1932. 28 units were in service with the CSD until 1938 as series 264.0 and nine more with the PKP as Pd12.

In order to obtain a powerful express locomotive for mountainous routes, Gölsdorf had a 4-6-0 locomotive with 1,820 mm wheels built from 1898 onwards. An outer frame with internal cylinders was unusual for heavy steam locomotives from the European mainland around the turn of the century. The positioning of the cylinders was probably necessary to comply with the loading gauge, since it was a two-cylinder compound engine with the largest low-pressure cylinder that had been installed up to that moment. The valve gear remained outside of the frame. A more than four meter long steam collection tank on the upper edge of the boiler was there to keep sufficient quantities of steam in stock for longer gradients.

The state railways received a total of 38 engines by 1903 and the southern railway four more. Despite their considerable size, the locomotives only achieved a calculated output of around 1,000 hp, which did not live up to expectations. Depending on the source, this was either related to the low quality of the coal used, to the high internal drag of the engine, or to the insufficient knowledge of the crews. After the BBÖ had taken over all examples from the kkStB and Südbahn, 19 units were converted to the class 409. The remaining 23 units that were not converted were retired by 1938.

In order to increase the speed of freight locomotives, Gölsdorf introduced a leading axle on the class 60 from 1895 onwards. The boiler was now higher, the firebox was above the last driving axle and the cylinders were behind the leading axle. This reduced the large overhanging masses, which improved smooth running. Many parts from the classes 30 and 59 were used. With their top speed of 60 km/h, they were also used in passenger and express service when needed.

Until 1910, the kkStB received a total of 297 that were operated with saturated steam. In addition, 22 were built with Clench steam dryers as class 60.500 and three with Pielock superheaters as class 60.800. The Südbahn received 73 of the saturated variant between 1900 and 1914. Since the locomotives were spread throughout Austria-Hungary, many came to Poland, Czechoslovakia, Italy, Yugoslavia and Romania after the First World War. Even after the Second World War, the ÖBB took over 20, the last of which were used until 1963.

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.

The class 79 emerged from a competition in which a freight locomotive for the Arlberg was sought. In addition to this, the classes 76 and 78 also competed, as well as the victorious class 73. The design from Floridsdorf had a Klose supporting tender and, like all the competitors, four coupled axles. The two machines differed in that one had an inside frame and one had an outside frame. Only the 79.02 came to the BBÖ, which remained in service until 1926.

The class 80 was created by superheating the class 180. At that time, however, Karl Gölsdorf generally designed the superheater surface to be small in order to be able to dispense with the expensive import of special lubricants for higher temperatures. Except for a slightly larger high-pressure cylinder, the differences to the 180 were limited.

The first production batch from 1909 to 1910 consisted of 36 examples, in which the high-pressure cylinder was controlled by a piston valve and the low-pressure cylinder by a slide valve. The next 104 examples from 1911 to 1915 only used piston valves. These two variants are known as 80.0 and 80.100 because of their running numbers.

The 80.179 is today being situated in Knittelfeld

Herbert Ortner / CC-BY 4.0

Between 1911 and 1919 the class 80.900 was built in parallel, which had a simple engine. Both cylinders had the same diameter as the high-pressure cylinder on the 80.0 and 80.100. With 212 vehicles, it reached a significantly larger number than the compound variant. Among them were eight pieces that went to the southern railway.

After the First World War, the BBÖ ordered further pieces of the simple variant and classified them as class 80.300. Five others had Lentz valve gear and a small-tube superheater with a significantly larger area, with the evaporation heating area being reduced. These locomotives were listed as 80.600.

Sectional drawing with dimensions

Die Lokomotive, April 1911

Other states from the former territory of the k.u.k. Monarchy subsequently ordered a larger number of identical locomotives. They were assigned to their fleet together with the locomotives taken over from pre-war production and given different designations. So they were called Tw12 in the PKP, class 28 in the JDŽ and series 50.0 in the CFR.

Since the BBÖ only had a few class 80 locomotives left, some of these were converted into simple locomotives. When the Reichsbahn took over the BBÖ in 1938, the class 80 was assigned to the class 57 according to the scheme. After the Second World War, the ÖBB took up this numbering and classified the compound engines as class 157 and the simple engines as class 57.

The class 88 of the kkStB designated small tank locomotives intended for traffic on branch lines. They drew their inspiration from five 0-4-0T locomotives built for the Kaiserin-Elisabeth-Bahn in 1880, which were also called class 88 at the beginning and were renumbered to class 188 in 1905. The new class 88 was built 47 times by Krauss in Linz between 1882 and 1885.

The last five were built for the Österreichische Lokaleisenbahngesellschaft (ÖLEG) and were slightly heavier than the 42 of the kkStB. Starting in 1892, they got new boilers. After World War I, they came to the state railways of Czechoslovakia, Italy, Poland, Romania and the Kingdom of Serbs, Croats, and Slovenes.