In 1851, Bavaria and Austria had sealed a state treaty that several railways should be built to connect the two countries. A total of 54 Series I express locomotives were procured for the first line to be opened from Vienna via Linz to Salzburg. The locomotives were built in several workshops: 18 in the Wiener Neustadt locomotive factory, 24 by the Staats-Eisenbahngesellschaft factory and six by Sigl. It was not until 1863 that the last six pieces followed from the KEB's own workshop. After the entire route had been opened, a big party was held in the Vienna Augarten on August 15, 1860, which was also attended by the passengers of the first train that had arrived from Munich via Salzburg with a Series I locomotive.

As was usual at the time, the locomotives did not have a driver's cab. Proper cabs were only retrofitted later, as were Kobel chimneys to protect against flying sparks. Despite the driving wheel diameter of only 1,580 mm, they were initially used in express train services.

Between 1869 and 1872, 30 more Series II locomotives followed, most of which had been manufactured by the KEB workshop. They had the same driving wheel diameter and the same wheel arrangement, but were slightly heavier. Both series were equipped with outside cylinders, but the series I still had an inner frame and the series II had an outer frame. The boiler pressure was now nine instead of seven bars. The engineer Johann Zeh installed the so-called Zehn flap, with the help of which one could direct air into the cylinders when the regulator was closed and whose compression could be used as an additional brake.

Schematic drawing of the Series I as delivered

Die Lokomotive, September 1907

In the 1880s, the Series I locomotives received new boilers that could be operated at 10 bars. The grate area was increased and the heating surface decreased, which improved their relation to each other and brought the boiler into line with the II series. These too were later operated with ten bars. The Series I locomotives survived with the k.k. State railways as series 12 until 1904, their successors became series 21, even came to the BBÖ and were retired in 1928.

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.

In the years 1879 and 1880, the Kaiserin-Elisabeth-Bahn procured a total of eight more 2-4-0 express locomotives from the workshops of the state railway company. The requirements specified were that 100 tonnes should be towed at 55 km/h or 200 tonnes at 27.5 km/h on a gradient of one percent. In order to achieve the necessary train loads on the curve radii from 280 meters, a great deal of development effort was put into the locomotives. This also included the Haswell corrugated iron firebox, which was only used in the 1870s and was not able to establish itself beyond that.

The biggest difference to the existing series I and II was that the diameter of the dring wheels was increased from 1,580 to 1,900 mm. Although the top speed was only increased from 70 to 80 km/h, this improved smooth running at higher speeds and reduced consumption and wear. The reduced pulling power due to the significantly larger wheels was compensated for by a higher boiler pressure of ten bars and a slightly larger cylinder diameter. In addition, it was about seven tonnes heavier than the KEB II and thus had a larger adhesive weight. 

Schematic drawing with dimensions

Die Lokomotive, June 1936

All in all, the A III was the most powerful of all Austrian 2-4-0 locomotives and also outperformed many 4-4-0 locomotives well into the 1890s. They were taken over by the kkStB in 1883 and initially referred to as A III. Later they became class 7 and got the numbers 7.01 to 7.08. The BBÖ also took over six more after the First World War and retired them between 1922 and 1929.

The class Z refers to rack locomotives in the Abt system which had three axles and a pure rack drive. They were based on the H 2/3, which the SLM had built for the Monte Generoso railway. Six locomotives were built for the Salzkammergut-Lokalbahn for use on the Schafberg railway, whose bodies were inclined by 17 percent according to the line. The EWA purchased five more for the Schneeberg railway, which were only inclined by twelve percent.

For downhill running they had an additional water tank to cool the cylinders when the Riggenbach counter-pressure brake was used. The Schneeberg railway equipped its locomotives with petroleum firing from 1900 onwards, which was undone during the First World War. In the fifties they received Giesl ejectors. Today three locomotives are still existing, two of them operational.

The Tyrolean State Railway built two lines, the northern one running between Innsbruck and Kufstein on the Bavarian border. Among the 26 locomotives purchased were eight Engerth-type supporting tender locomotives, which were intended for operation with freight trains. Their chassis consisted of three driving axles with a wheel diameter of 1,264 mm and a two-axle tender.

Five of the eight machines were given the names of places along the route. These were “Amras”, “Hall”, “Innsbruck”, “Kufstein” and “Martinswand”. The remaining three were called “Achensee”, “Inn” and “Tirol”. As early as 1859, just a year after the line opened, the Tyrolean State Railway was taken over by the Southern Railway. These locomotives were first renumbered as class 18 and later as class 25.