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](./data/photos/kkstb_80.jpg)
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](./data/photos/kkstb_80_3.jpg)
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.