German Federal Railway class 151

When the demand for high-speed freight locomotives increased in the 1960s, a further development of the E 50 was examined. The requirements stipulated on gradients of 0.5 percent to run express freight trains with 120 km/h and 1.000 tonnes or regular freight trains with 80 km/h and 2.000 tonnes. A change in the gear ratio of the E 50 failed because its traction motors, which were weaker than those of other standard electric locomotives, would not have been sufficient at higher speeds. However, a completely new development was ruled out due to time constraints. The solution now consisted of finding a compromise between the proven technology of standard locomotives and more modern assemblies.

Since the traction motors of the E 50 were not suitable for a larger increase in output, the traction motors from the E 10 and E 40 were further developed. With a total of six of these traction motors, an hourly output of 6,288 kW and a braking power of 6,600 kW over a short period could be achieved. Since the bogies and the electrical equipment of the E 50 were not suitable for this power, the technology of the class 103 was used. To facilitate maintenance, new design principles were used, which had also been used with the 103. The entire paneling of the engine room consisted of three large hoods, which, like the driver's cabs, could be removed as a whole. Compared to the previous class, the interior of the driver's cabs has been modernized in terms of comfort and ergonomics.

According to their design, the locomotives were used almost exclusively in front of fast or heavy freight trains. Nevertheless, they had the necessary equipment to be able to pull passenger trains when there was a shortage of locomotives. Only on the Franconian Forest ramp they were used in front of scheduled passenger trains, which has not been permitted since 2003 due to the lack of door blocking.

The heaviest freight trains used in Germany were ore trains, initially weighing 4,000 and later 6,000 tonnes, which ran from the North Sea ports to the steelworks inland and were each pulled by two class 151 locomotives. Since these loads were too great for the screw couplings common in Central Europe, 20 locomotives and a sufficient number of freight cars were equipped with central buffer couplings. When these services were discontinued in the 1990s, the locomotives were fitted with screw couplings again and assigned to other areas of application.

In contrast to the other standard locomotives, most of the locomotives remained painted in their original chrome oxide green color scheme into the 1990s. Their importance decreased with the increasing number of four-axle three-phase current locomotives for freight train use, since the DB wanted to quickly part with locomotives with three-axle bogies due to the increased wear on wheels and rails.

Since 2003, they have mostly only been used to push vehicles up ramps. At the same time, sales began to private companies, who will continue to use the locomotives for longer due to their performance and reliability. The largest customer was a consortium of Railpool and Toshiba, which signed the contract for the purchase of 100 of the 170 machines manufactured in 2017. At Deutsche Bahn, the locomotives are now being phased out when the maintenance deadlines expire.