road than on", and that their weight damaged road surfaces. They were also considered to be energy hungry, consuming 2.9 kWh/km—compared with between 2.0 kWh/km and 2.4 kWh/km for trams with much greater capacity. One of Ghent's gyrobuses has been preserved and restored, and is displayed at the VLATAM-museum in Antwerp. It is sometimes shown (and used to carry passengers) at Belgian exhibitions, transport enthusiasts' bazaars, etc. The tram depot in Merelbeke has been closed since 1998, but it still stands, as it is protected by the law. Advantages Quiet "Pollution-free" (Pollution confined to generators on electric power grid.) Runs without rails (An advantage because the route can be varied at will.) Can operate flexibly at varying distances Disadvantages Weight: a bus which can carry 20 persons and has a range of requires a flywheel weighing about 3 tons. The flywheel, which turns at 3000 revolutions per minute, requires special attachment and security—because the external speed of the disk is . Driving a gyrobus has the added complexity that the flywheel acts as a gyroscope that will resist changes in orientation, for example when a bus tilts while making a turn, assuming that the flywheel has a horizontal rotation axis. This effect can be counteracted by using two coaxial contra-rotating flywheels. Further developments Since 2005 Dresden, Germany has had an Autotram, a vehicle that uses a fuel cell as its main source of energy and a small flywheel for regenerative braking only. Gallery See also Electric bus List of buses OLEV References External links Electric buses in citytransport.info - with a photograph showing two gyrobuses at a charging point . Buses Worldwide - some of the information contained in this article comes from the January / February 2005 issue of "BusesWorldWide" Magazine as issued by the organisation of the same name. Technology in Parry People Movers—shows how the same technology is being transferred to ultralight Trams Concept of Mechanically Powered Gyrobus Buses by type Electric buses ja:フライホイール・バッテリー#自動車