The class 252 or later DB class 156 refers to a series of four heavy electric locomotives that the Reichsbahn developed as the last new model. They came about because, in view of the oil crisis of the 1980s, it was decided that many main lines should be further electrified on a large scale and a heavy six-axle model was needed to supplement the newly developed class 243. In addition, a top speed of 160 km/h was initially planned, since important routes were to be upgraded for this speed.

Many parts from the 243 were used to reduce maintenance costs, but the six instead of four traction motors were slightly more powerful. The driver's cab was largely adopted because it corresponded to modern standards at the time and made it easier to exchange personnel between the two types. The shape of the locomotive body was tested in the wind tunnel and shows similarities to the Bundesbahn's class 120, which had been developed a few years earlier. In the end, the speed was only set at 125 km/h, since many lines were not yet designed for higher speeds and this resulted in higher tractive effort. This allowed trains of 3,000 tonnes to be towed at 100 km/h, and it was also possible to tow 1,800 tonnes at 120 km/h without a power reserve.

Although the four prototypes proved themselves, series production did not materialize as a result of the merger with the Bundesbahn. Although they wanted to continue producing an electric locomotive for the Reichsbahn to secure jobs, the decision was made in favor of the faster class 112, which was based on the 243 or new 143. Other disadvantages for the 252 and 156 were that they only wanted to buy three-phase locomotives for heavy duty and generally wanted to do without six-axle locomotives.

However, the four units continued to be used and some were even used to pull heavy express trains. In 1998 they were assigned to DB Cargo and only used in front of freight trains until they were parked in 2002 and were to be sold. A year later, the Mitteldeutsche Eisenbahn GmbH (MEG) was found to be a customer, whose fleet consists mostly of vehicles from the former GDR. It uses the locomotives with the numbers 801 to 804 primarily in central Germany and in the direction of the Rostock port in front of heavy freight trains with heating oil or cement. They also regularly reach the Ruhr area.