Replacing conventional fuel in public transportation is a challenge far older and more complex than we might imagine. The first alternative that comes to mind is the trolleybus, which operates without issues in many parts of the world. But in the 1940s, a Swiss engineer created the Gyrobus, based on a flywheel spinning at 3,000 revolutions per minute to store energy. With recharges at strategic stops, the Gyrobus could cover urban distances efficiently and quietly, without relying on external wiring.
Anyone interested in exploring the history of emission-free vehicles will need to travel, one way or another, to April 29, 1882, when Ernst Werner von Siemens presented his Elektromote on the streets of Halensee. That is how the first trolleybus was born, and today we can see its descendants in action, running through more than 300 cities and towns around the world.
However, the trolleybus has not always enjoyed great popularity. The main criticism is, without a doubt, the need for special wiring, which not only limits movement but is also very costly to expand and not very pleasant to look at. In 1946, many Swiss cities adopted the trolleybus, but over time, its weaknesses became a bigger problem to solve: traditional buses were too noisy, and some routes did not justify such a large investment. The answer was the Gyrobus.
Gyrobus: A Giant Wheel to Go Everywhere
The Gyrobus was the creation of Bjarne Storsand, chief engineer at Maschinenfabrik Oerlikon (now a remote part of the ABB Group). The original plan was to incorporate its flywheel-based technology into short-distance trains with industrial applications, but it found a place in public transport. The Gyrobus prototype was built on the chassis of an FBW cargo truck from 1932. The flywheel, weighing 1.5 tons and measuring 1.6 meters in diameter, was installed in the center of the vehicle, completely sealed. Its special chamber was injected with hydrogen at low pressure (0.7 bar or 700 hectopascals) to reduce air resistance. Under normal conditions, the flywheel spun at about 3,000 revolutions per minute, but in emergencies it could reduce its rotation to 1,500 RPM, affecting the vehicle's final performance.
Speaking of performance, several sources indicate that the Gyrobus could cover a distance of 5 or 6 kilometers (including stops and traffic) with a full charge, and isolated reports from the Yverdon-les-Bains station mention 10 kilometers. A full recharge starting with the flywheel stopped could take 40 minutes, but once in motion, the Gyrobus needed a minimum of 120 seconds. The units were used in Switzerland, Belgium, and the Belgian Congo, where drivers eager to take shortcuts on poor, unpaved roads caused significant damage to the flywheel and its mechanism.
In the end, it was the high consumption of electrical energy (and cheap conventional fuel) that sealed the fate of the Gyrobus fleet... not to mention the small detail of having a giant 1.5-ton wheel injected with hydrogen spinning at 3,000 RPM very close to passengers. Something tells me its story would be different today...
Sources: Station Gossip, Proaktiva
