Prussian G 9

Although Prussia had already built a superheated freight locomotive with the G 8 from 1902, they were not yet completely convinced of the superheater technology and thus designed the G 9. The G 7 was used as the basis for the development, but one could now Install a larger boiler due to the meanwhile higher permissible axle loads. 

Initially the locomotives were also put into service as the G 7, but soon the new designation G 9 was assigned to them. This made sense, since the new locomotives were significantly more powerful than the G 7 due to the larger boiler, a cylinder diameter increased by 30 mm and a weight increased by a little more than five tonnes. Nevertheless, the power remained noticeably below that of the G 8, which in turn demonstrated the power of a locomotive in the same weight class that used the new, not yet fully matured superheater technology.

The first ten received inside Allan valve gear, but the rest used the usual outside Walschaerts valve gear. Between 1908 and 1911, Schichau and other manufacturers produced exactly 200 of these, which were mainly used to transport ore from the North Sea to the Ruhr area. A few years later, only 133 came to the Reichsbahn, which were assigned to class 55^23-24. Of these, 36 were superheated in the years that followed, bringing them closer to the G 8 in terms of power and speed.

After the war, the former G 9 were used in both parts of Germany, with the exception of a few examples which remained abroad. In the western zones, there was no need for these saturated locomotives and they were retired by 1949. This was different in the Soviet occupation zone, which is why they were included in the inventory of the Reichsbahn. 55 2361 was the last to be retired there in 1961.