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.