EW90 is the name for German Reichsbahn ET 165 electric multiple units working for Polish State Railways (PKP) after World War II.

The German ET 165 units were built in the period between 1928 and 1936 to service Berlin S-Bahn lines.

While many units of this type were destroyed during the war, 189 ET 165, ET 166 and ET 167 vehicles were stabled in Schweidnitz (Świdnica), which after 1945 became part of Poland.

From 1951 to 1957 were refurbished in Lubań as EW90, EW91 and EW92 units to service SKM lines in the Tricity area of Gdańsk, Sopot and Gdynia.

Two-step reduction of engine excitation (up to 50%) is made by a short-circuit of parts of main poles.