Boston Neoplan DMA-460LF dual-mode trolleybus, operating in diesel mode (with its trolley poles lowered)

A dual-mode bus is a bus that can run independently on power from two different sources, typically electricity from overhead lines like a trolleybus or from batteries like a hybrid bus, alternated with conventional fossil fuel (generally diesel fuel). In contrast to other hybrid buses, dual-mode buses can run forever exclusively on their electric power source (wires). Several of the examples listed below involve the use of dual-mode buses to travel through a tunnel on electric overhead power.

Many modern trolleybuses are equipped with auxiliary propulsion systems, either using a small diesel engine or battery power, allowing movement away from the overhead wires, called "off-wire" movement, but such vehicles are generally not considered to be dual-mode buses if their off-wire capability is very limited. Examples include the fleet of about 300 trolleybuses in San Francisco[1] and the trolleybuses used on a 2005-opened system in Rome, Italy,[2] which are capable of running on battery power only for short distances or short periods of time before needing recharging. The Rome vehicles are powered from overhead trolley wires over most of the 11.5-km route and only use battery power on the 500-metre section closest to the city centre.[2] Dual mode trolleybuses in a number of Chinese cities can operate significant distances (8 to 10 km) off-wire on battery power.[3]


The Downtown Seattle Transit Tunnel was served exclusively by dual-mode buses from its opening in 1990 until 2004.
A dual-mode bus in Ploiești, Romania, 2010.
This transport-related list is incomplete; you can help by adding missing items. (August 2008)

See also


  1. ^ "About Trolley Buses". San Francisco MTA. Archived from the original on 2011-12-18. Retrieved 2009-12-15.
  2. ^ a b Webb, Mary (ed.) (2009). Jane's Urban Transport Systems 2009-2010, p. 195. Coulsdon (UK): Jane's Information Group. ISBN 978-0-7106-2903-6.
  3. ^ a b Luan, Xiaona 栾晓娜 (2014-06-26). 上海无轨电车"复兴":全换成新型辫子车 车辆增加两倍. 东方网 (in Chinese). Archived from the original on 2017-10-11. Retrieved 2017-10-11.
  4. ^ 北京多措并举治理PM2.5 一微克一微克往下抠. 新华网 (in Chinese). 2020-01-15. Archived from the original on 2020-01-16. Retrieved 2020-03-14.
  5. ^ Chick, Dave. "Castellon". British Trolleybus Society. Archived from the original on January 6, 2009. Retrieved 2009-01-10.
  6. ^ "Castellón-de-la-Playa (sic) Trolleybus Photos". 18 December 2008. Archived from the original on 2009-02-12. Retrieved 2009-01-10.
  7. ^ "A First in Spain: Optiguide for Castellon's Trolleybus Line". Innovations Report. 2008-07-07. Archived from the original on 2009-02-18. Retrieved 2009-01-11.
  8. ^ "Castellón de la playa notes". 3 July 2008. Archived from the original on 2009-02-12. Retrieved 2009-01-10.
  9. ^ "Retired - Breda 5000 Dual-Mode Bus". Metro Online. Archived from the original on 2010-05-28. Retrieved 2009-12-04.
  10. ^ "Breda Articulated Trolley Bus". King County. Archived from the original on 2014-10-07. Retrieved 2009-12-04.

Media related to Dual-mode buses at Wikimedia Commons