26-5174 SISU SWS Trolley

Brand: SISU
Series: SWS-trolley
Ref : 1979

(pages : 8)

Among the most unusual vehicles developed by the Finnish automotive industry is undoubtedly the SWS Trolley, a hybrid trolleybus prototype unveiled in 1979.

Its name, «SWS,» comes from the initials of the three companies that collaborated on its design:

– Suomen Autoteollisuus (Sisu): chassis manufacturer
– Wiima: body manufacturer
– Strömberg: Specialist in Electrical Equipment

Developed at the request of the Helsinki Transport Authority (HKL), the SWS was designed to explore the future of electric urban transportation in Finland. Unlike conventional trolleybuses, it could operate both under overhead power lines and autonomously thanks to an onboard diesel generator. This hybrid technology was particularly innovative in the late 1970s.

The vehicle was built on a chassis derived from the Sisu BT-69 and used an asynchronous electric motor developed by Strömberg, a highly advanced solution for its time. It could accommodate approximately 70 passengers and delivered a maximum power output of 200 kW.

The prototype was tested in Helsinki for several years before participating in 1985 in the European COST 303 program, which was designed to compare the continent’s most modern trolleybuses. As part of this program, the SWS was even shipped to Belgium, where it operated temporarily in Ghent, making it one of the few Sisu vehicles to have been operated outside of Finland.

No other units were built, and the project remained at the prototype stage. This one-off production explains the exceptional scarcity of period documentation on the SWS. Brochures, press kits, and official photographs are now very difficult to find and serve as valuable records of one of the most ambitious endeavors undertaken by the Finnish automotive industry in the field of electric urban transportation.

A particularly rare document featuring factory photographs and vintage press photos.