Between 1924 and 1932, the Reichsbahn procured a series of new railcars for the Hamburg-Altona city and suburban railway, which had been electrified with 6,300 V and 25 Hz since 1907, in order to supplement the existing fleet of railcars and to partially replace the steam trains.

Similar to the older railcars, the new ones consisted of individual compartments for second and third class, each with its own door on each side, as was standard for Prussian compartment coaches at the time. This time, however, the car bodies were constructed in a more modern all-steel construction with barrel roofs. Each unit consisted of two parts with a total of three two-axle bogies, of which the middle one between the cars was designed as a Jakobs bogie. The end bogie of one of the two cars was powered on both axles with a total of 300 kW. All electrical equipment came from BBC (Brown, Boveri & Cie.), while the mechanical components came from Waggonfabrik Wismar, WUMAG (Görlitz) and WASSEG (AEG/SSW).

When the new S-Bahn with direct current via conductor rails was introduced on the same tracks from 1940, the vehicle generations with overhead lines and conductor rails were operated in parallel to these. AC operation was discontinued in 1955 without a planned renaming to ET 99. Only two of the vehicles were converted to baggage railcars for the new power system and designated ET 174 001 and 002 by the Bundesbahn. These were scrapped in 1967.