Prussian battery railcar type Wittfeld AT₃

The Wittfeld-type battery railcars were procured by the Prussian State Railways from 1907 in order to obtain a cheap and easy-to-operate means of transport for passenger transport on branch lines. The designation came from engineer Gustav Wittfeld, who designed the concept for these vehicles at the Ministry of Public Works. The requirement was that around 100 people should be transported at 50 km/h and that the capacity of the batteries should be sufficient for a range of 100 km. Since the acid in the batteries at that time gave off larger amounts of foul-smelling gases, the desire for a separation of the passenger compartment from the batteries was also expressed, as was not the case with the first battery-powered railcars.

The first of the railcars built consisted of two halves, each with two axles, of which the inner one was powered. At each end there was a hood for accommodating the batteries. Since these were very heavy and brought the axle load to a level that was critical for branch lines, the individual axles at the ends were replaced by two steering axles from 1913. All existing copies were also retrofitted in this way. To increase the passenger capacity, a passenger car was sometimes attached to the railcars. Since this was only a temporary solution, eight examples were later built with a trailer. This also received the traction motors, while the batteries remained in the end cars.

Inside, the vehicles differed depending on the requirements, but mostly they only had third and fourth class seats. In the latter there were also some standing places, more were made available in the rear driver's cab. In some railcars there was a second class compartment and/or a luggage compartment and in some cases toilets.

The vehicles were designated AT₃ from 1909 and were initially used primarily in Poland. Even after the First World War, some came to Poland as reparations. In service with the Reichsbahn, the area of application expanded to other regions in Germany. After the Second World War, the remaining railcars on the territory of the Federal Railways were reconditioned, since a large number of them were no longer in a roadworthy condition. Depending on the type of electrical equipment, they were designated ETA 177, 178 and 180 and remained in use until 1964. In the GDR, her life ended in 1954 because there were no funds for reconstruction.