Like the ES 1 to ES 3, the EG 502 to EG 505 were a series of experimental electric locomotives that were all mechanically developed and built by Hanomag, but whose electrical equipment came from different manufacturers. The aim was to examine different drive technology solutions under the same conditions.

The electrical part of the four locomotives came from AEG, Felten & Guilleaume, Brown Boveri & Cie. and the Siemens-Schuckert-Werke. Two locomotives each had an hourly output of 800 and 600 hp (588 or 441 kW) and due to the different designs of the motors and gearboxes, there were significantly different starting tractive forces. The chassis consisted of four wheelsets fixed in the frame, which were arranged in two groups of two each. In the middle was the jackshaft, via which all wheel sets were driven by means of coupling rods. The different weights of the different versions resulted in an axle load of between 15 and 16.7 tonnes.

The test runs on the test track between Dessau and Bitterfeld were positive for all four locomotives, which is why a direct transition to planned operation was planned. When the start of the First World War meant the end of electrical operations in the Halle subdivision network, they were transferred to Silesia for use on the mountainous routes there. After returning to Central Germany in 1923, it quickly became apparent that the locomotives were no longer up to the increased demands in terms of power and speed. Like some other early electric locomotives, they were finally handed over to the Wiesen- and Wehratalbahn, which were electrified in 1913. They were given the numbers E 70 02 to E 70 05 by the Reichsbahn and were retired by 1930.