The constantly increasing loads on freight trains presented the German State Railroad Company with immense problems in the middle of the 1930s. The railroad saw the solution in the development of increasingly larger and more powerful locomotives. The class 45 developed by Henschel in 1936 was the final statement on the most powerful German steam locomotive. Its evaporative heating area was almost 270 square meters or 2,905 square feet and was over 50% larger than the later classes 50 and 52. The 2,800 hp resulting from this and the maximum speed of 90 km/h or 56 mph were impressive figures for a freight locomotive. And yet the class 45 was not a great success. The expense of the design and the constantly occurring damage to the boiler shows that the development had reached its limits. By 1940 a total of only 28 units had been built, and an order for another 103 units was canceled in 1941. Other priorities were now more important than pure power generation: The class 45 was never maintenance-friendly and efficient. The German Federal Railroad also had no interest in further purchases of this design, since there were plenty of large freight locomotives available with the class 44. And yet several locomotives were equipped with new appliances and were modernized. The units were not retired until after 1968.