With the delivery in 1979/80 of five class 120 pre-production series locomotives, three-phase asynchronous motors were used for the first time in the world on a standard gauge locomotive. These motors can be controlled smoothly without steps. Forerunners and test units were the class 202. For a long time unsolvable difficulties faced the advantages of three-phase motors. The three-phase motor could not be made flexible and thereby usable for practical operations until the advent of electronic switching and control technology. The class 120 units were designed as general-purpose motive power that could pull express InterCity trains, regional trains, and commuter trains as well as freight trains. Externally the prototypes impressed you with their length of 19,200 mm / 63 feet that made them almost as long as the classes 103, 150, and 151. They differed from the latter in having only two-axle trucks of a completely new design. A BBC hollow shaft universal joint drive served to transmit power. The mainframe and lightweight construction locomotive body formed a self-supporting design. After extensive test runs, all of the units were authorized for 200 km/h / 125 mph. On October 17, 1984, road number 120 001 even reached a world record for three-phase current locomotives with 265 km/h / 165 mph.
Between 1987 and 1989 the regular production locomotives road numbers 120 101-160 were built by AEG, BBC, Siemens, Krauss-Maffei, Krupp, and Henschel with numerous improvements such as time-division shuttle train and multiple unit control, reinforced line brakes, auxiliary electro-pneumatic brakes as well as automatic running and brake controls with anti-wheel slip.
The five pre-production locomotives were given the designation 752 001-005 in the early part of 1989 and were now available to the railroad's central offices as experimental locomotives. After delivery of the regular production class 120 locomotives, they were no longer absolutely needed in scheduled service. Road number 752 001 of the railroad's Minden central office took on a special status here as it was equipped for a maximum speed of 280 km/h / 175 mph. Road numbers 752 002, 003, and 005 were retired on January 1, 2001, and road number 752 001 on May 28, 2004 after a serious accident on April 21, 2004 in Süssen. Road number 752 004 held on a few more years until January 1, 2012. The first two fell victim to dismantling. Yet road number 120 003 has been enhancing the Augsburg Railroad Park since February of 2006. Road number 120 004 has been enriching the DB Museum in Koblenz-Lützel since 2012, and the orient red road number 120 005 has been on loan to the Weimar Railroad Museum since April of 2010.