The machines ES 51 to ES 57 were heavy electric locomotives for use in front of express trains. They were later designated E 06 and additional were built by the Reichsbahn as E 061. Due to their drive technology, which was no longer up-to-date by the time they were put into service, both series only made it to a total of twelve units. The first series was delivered to the newly founded Reichsbahn in 1924 and 1925 and still had Prussian numbers. Another five machines were delivered in 1928 and taken over directly as E 061. Externally, these differed only by a greater length.
The locomotives had the wheel arrangement 2-C-2 and were designed for 110 km/h with a driving wheel diameter of 1,600 mm. Compared to the single-axle drive of other machines from that time, power was still provided by a single, slow-running electric motor with an hourly output of 2,780 and a continuous output of 2,330 kW. Because of its large diameter, a clearly visible bulge had to be made on the roof. The first series was powered by an oil-immersed transformer with forced circulation for cooling. The later machines received a dry-type transformer with air cooling.
The power was transmitted via connecting rods and coupling rods, which were arranged in a triangular shape and were partly inside the locomotive body. Since the traction motor was not located in the middle, the connections between the connecting rods and the coupling rods were on two jackshafts which, depending on the direction of travel, were in front of the first and between the second and third coupling axles. This construction was not suitable for higher speeds and meant a significant maintenance effort.
Despite the lack of series production, operations continued until 1944/1945. The machines handed over to the Soviet Union after the Second World War came back to the GDR in 1955, but were immediately scrapped due to their condition.