German Reichsbahn E 52

In the early Twenties, the Bavarian group administration of the Reichsbahn ordered 35 electric locomotives for heavy passenger and express traffic and 34 for heavy freight traffic. The former was procured as the EP 5 and renamed the E 52 in 1927, the latter was already delivered as the E 91. Although the mechanic part for both classes came from Maffei and Krauss, the electrics were standardized as far as possible. This part came from WASSEG, a cooperation between Siemens-Halske and AEG.

The E 52 was specified to transport a 500-tonne train at 90 km/h on the flat and to be able to accelerate it from a standstill to 50 km/h in two minutes on a gradient of one percent. In order to achieve this, it got the same four motors as the E 91 with a total hourly output of 2,200 kW and four driven axles. Four additional axles were required to carry the weight. With a total of 140 tonnes, it is still the heaviest electric locomotive that has ever been in use in Germany.

The driven axles were divided into two groups. Two traction motors each acted on a reduction gear and drove two axles via coupling rods. The tap changer was designed in such a way that only one traction motor is active when starting off in the first notch. These axles were mounted in the frame, with the first being laterally shiftable by five millimeters and the second and third being shiftable by ten millimeters each and having weakened wheel flanges. The bogies could each be moved by 80 millimeters.

With the DRG, the locomotives were only used in Bavaria. During the war, three units had to be written off and after the war, the Bundesbahn had to decommission a further three of the machines that had been taken over due to damage. In 1968 the rest were redesignated as the class 152. As early as 1966, their area of operation was concentrated in Kaiserslautern, where they mainly pulled freight trains. Soon they were also used for piloting and pushing services. After all had been retired by 1973, some were used as stationary transformer locomotives until the mid-1980s. One machine is still preserved, which has been in the Nuremberg Transport Museum since 2014 and is again labeled EP 5.