In addition to the class 01, the 03 was also taken on in order to develop a variant with streamlined fairing and three cylinders. The result was the class 0310, which was designed for 150 km/h and was only certified for 140 from 1940. Instead of the 140 ordered, only 60 were finally completed, as production had been focused on freight locomotives since the outbreak of war. In the case of locomotives supplied by Borsig and Krauss-Maffei, the fairing was pulled over the entire drive train and running gear to just above the upper edge of the rails, while Krupp left a cutout in the area of the drivers just above the axles. Since the original locomotive was only designed for two cylinders, the steam of the 0310 could not be optimally distributed between the three cylinders and the indicated power fell a bit compared to the 03.
Although streamlined locomotives had about 50% less drag, the fairing not only restricted accessibility for maintenance, but also limited engine cooling. As early as 1942, the fairing was gradually removed from the fully encased locomotives to a point on above the drivers. For the time being, the Krupp locomotives continued to run with their cut-out fairings. After the war, traffic on both sides of the Iron Curtain was initially not possible at the speeds at which streamlining offered advantages over conventional locomotives. Since these were also often in very poor condition, they were completely removed from all locomotives. From now on, a striking feature of these engines was the slanted top smoke box, but some rebuilds also included a new smoke box with a round door.
In the case of the 26 locomotives of the Bundesbahn, the later rebuilds were mainly limited to replacing the St 47 K boilers which became brittle over time with new ones made of a more durable alloy. Although the new boilers had a combustion chamber, the output was only slightly higher than before. They were retired between the end of 1965 and the end of 1966 and finally scrapped without exception.
Since the shortage of locomotives at the Reichsbahn was more serious, 16 of the 17 locomotives of the 0310 were included in the reconstruction program. The most modern construction principles were used in the subsequent fundamental rebuilding in order to be able to use the locomotives for a few more years in front of the highest-quality express trains. In the period when their sisters were already being phased out by the Bundesbahn, almost all engines in the GDR were given oil firing. Especially with the latter, a significant increase in power was recorded, some claims are as high as 2,350 hp. After some of the reconstructed engines had achieved monthly mileages of more than 20,000 km, they were retired by 1980.
