The later E 77 was one of the first series of electric locomotives that the Reichsbahn procured simultaneously for several directorates, i.e. for several former state railways. They were developed as lighter multi-purpose locomotives, which should primarily be used in front of freight trains and, if necessary, also in front of passenger trains. At the time of their commissioning, the Munich engines were given the Bavarian designation EG 3 and the Halle machines were given the consecutive Prussian numbers EG 701 to EG 725.

The locomotives consisted of two chassis groups supporting a three-part body. Each chassis consisted of a carrying axle with 1,000 mm wheels and two powered axles with 1,400 mm wheel diameters. In each of these two chassis was an electric motor with an hourly output of 940 kW and a continuous output of 800 kW. After the rotational speed was reduced by a reduction gear, the motors delivered their power to the two coupled axles via a crankshaft and diagonal rods. The two outer parts of the car body were firmly attached to the running gear. In addition to some of the electrical equipment, they accommodated the driver's cabs, which initially had connecting doors on the front sides, which were later removed. The middle part of the body formed a bridge between the ball pivots of the chassis groups and contained the transformer. Bellows and transition plates ensured that one could move between the driver's cabs or access the electrical equipment without having to leave the locomotive.

The 56 pieces delivered between 1924 and 1926 were not completely convincing due to some technical problems. The initially unsatisfactory running characteristics were subsequently improved by installing the carrying axles movable with spring return. However, this conversion could not prevent the engines from continuing to run unsteady in the top ten km/h of their speed range. Another point of criticism were the connections between the three parts of the body, which contained many moving electrical connections. The latter were often the reason for problems and defects.

In the course of time, all Munich locomotives ended up in the Reichsbahn divisions in Halle and Hanover. After the war, three locomotives were too badly damaged to repair. Of the 53 remaining, 42 went to the Soviet Union. Individual parts were also taken away by the rest, so that they could no longer be used. In 1952 and 1953, 38 returned to the GDR, of which only ten could be refurbished. These were used until enough new electric locomotives were available, so that all but E 77 10 were retired by 1968.