German Reichsbahn H 02 1001

In the 1920s, Stephan Löffler developed the basics for a steam locomotive boiler at the TH Berlin-Charlottenburg that worked at a pressure of 120 bars (1,740 psi). The BMAG took advantage of this and built the H 02 1001 for the Reichsbahn in 1930. It was hoped that a coal saving of 42 percent would be achieved. It used the chassis of a class 01 locomotive, but was classified into class 02 due to the compound engine. 

The H 02 1001 had a firebox made of parallel tubes. The two outside high-pressure cylinders had a diameter of only 220 mm and were fed by steam that had passed through a three-stage superheater. Before the steam was fed into the inner low-pressure cylinder with a diameter of 600 mm, it passed through another reheater and so still had a pressure of 13 or 14 bars.

However, various problems arose again and again during the trials. These included burst superheater tubes or leaks in the high-pressure cylinders. In reality, only about 20 percent of coal was saved, which did not justify the complicated design and the many problems. The locomotive was therefore returned to the BMAG in 1934. After sitting there unused for eleven years, it was scrapped.