SWS, sWS, or SWs my refer to:
SWS is a hybrid trolleybus prototype that was developed and produced by three Finnish companies Suomen Autoteollisuus (SAT), Wiima and Strömberg in 1979.
The Helsinki City Transport (HKL) ordered the prototype to gain experience for the future public transportation strategy for city of Helsinki. The trolleybus got its power from the overhead wires, but for wireless parts it had a diesel generator as a power source. The prototype contained advanced technology.
The SWS prototype participated in COST 303 project in 1985 among other corresponding prototypes. As a part of the project, SWS was shipped to Belgium, where it served for half year in city of Ghent.
Eventually, trolleybus transport was seen too expensive compared to the conventional diesel option, and therefore the City of Helsinki decided to discontinue the trolleybus service and replace it by diesel buses. The SWS trolleybus was kept for possible further investigation.