The E 40 – Backbone of Freight Service. The class E 40/140 also came from the new procurement program of the Fifties. From a technical point of view the class E 40 is a class E 10.1 modified for freight service. It had the same locomotive body, almost the same mechanical and electrical systems, but it differed in several features from its faster siblings. The class E 40 had no electric brakes, a different gear ratio, which meant a lower top speed, and a different roof with fewer ventilation grills. The classic chrome oxide green was chosen for the paint scheme; the elegant blue was kept only for express locomotives. The class E 40, from 1968 on designated as the class 140, was designed for medium heavy freight service, but it wandered into other types of service, particularly when the top speed was raised from 100 km/h / 63 mph to 110 km/h / 69 mph. It could be seen pulling "Silberlinge" commuter cars and during the 1972 Olympic Games in Munich in S-Bahn service too. The main area of use remained and still is freight service. Like all other locomotives, the class E 40/140 underwent modernization programs, which changed the appearance of the locomotives markedly in addition to different paint schemes. Thirty one of the class E 40 locomotives were specially equipped with direct current resistance brakes for use on steep grades such as the Höllentalbahn or Valley of Hell Railroad. They were designated as the class E 40.11 and later starting in 1968 as the class 139. Later, the remaining class 139 locomotives were assembled together in Munich, where they were used along with the class 140 locomotives in service up to the Brenner Pass. The class E 40/140, with its sub-variations, was the locomotive type built in the largest quantities in the standard design program of the new German Federal Railroad. A total of 879 units were mainly responsible for medium heavy freight service over a period of decades. Except for a few locomotives, they are in the process of being retired or are already completely retired.