The first serial units went into service in 1956 and started with number E 10 101 (class E 10.1). As opposed to class E 40 these units were equipped with a rheostatic/regenerative brake, which also accounted for the difference in the roof design between the two classes. Starting in December 1956 a total of 379 locomotives in several series were delivered by the manufacturers (Krupp, Henschel, Krauss-Maffei (mechanical parts); Siemens, AEG, BBC (electrical parts). Starting with E 10 288 the new body used with E 10.12 (see below), the so-called "crease" ("Bügelfalte") type, was also applied to all regular E 10 machines. Thereafter these locomotives were sometimes designated as class E 10.3. One locomotive (designated 750 001) served as a service locomotive for the Central Office of the German Federal Railways in Minden ("BZA Minden", or "Bahnzentralamt") from 1989 to 1996. The earlier units up to E10 287 became E10.1, then 110.1 in 1968; they were nicknamed ""Kasten"", for box.