After only eight of the heavy class 280 mountain express locomotive, Gölsdorf built two more in 1909 which had a Schmidt superheater instead of the Clench steam drier. Apart from the superheater and somewhat larger high pressure cylinders, they were nearly identical to the 280. So they also had the same chassis configuration with 26 mm lateral play on the second and fifth driving axles. Even the power output remained roughly the same with 1,645 hp.
After the two prototypes with slide valves, 26 more locomotives were built between 1911 and 1914 which had piston valves. These locomotives were numbered in the 380.100 range and thanks to an additional oil firing, they could reach up to 2,100 hp for short periods. After World War I, only twelve stayed with the BBÖ. These were designated class 589 by the Reichsbahn from 1938 and after the war, none was remaining. From the locomotives which did not stay in Austria after World War I, nine had come to Italy as FS class 479 and seven had come to Yugoslavia as JDŽ class 07. Today, only 380.122 is surviving in Budapest.