Bochum - Eisenbahnmuseum Dahlhausen ET 165 080 S-Bahn-Wagen der Bauart Stadtbahn Baujahr 1928
In the period between 1928 and 1945 it serviced Berlin S-Bahn lines. After Second World War 54 units of this type were brought to Poland to service SKM line in Tricity. It was necessary to rebuilt cars to change power supply from third rail system into pantographs. EW90 EMUs finished their service in 1976 when power supply on SKM line changed from 800 V. into 3 000 V.
Each unit consisted of two cars: engine car and trailer. It was possible to connect four units in order to gain eight car train. GBM-700 type electric engines used in EW90, EW91 and EW92 units have 4 main poles and 4 commutation poles. Two-step reduction of engine excitation (up to 50%)is made by short-circuit of parts of main poles. Engines cooling is made with a fan installed on engines' shafts.