Duo bus

from Wikipedia, the free encyclopedia
Freiburg im Üechtland : Duo bus type NGT 204 F in diesel mode, the bars are removed. Unlike pure trolley buses or trolley buses with auxiliary drive Duo buses need in Switzerland license plates
Boston: Duo bus of the type Neoplan AN 460 LF, also in diesel mode
Esslingen: this O 405 GTD duo bus is also in diesel mode
With 236 cars built, the ADPB 350 from Breda - the abbreviation stands for articulated dual-power bus - is the most built duo bus in the world
A PER 180 H, here in Grenoble in 1984
A N 6121 procured by Neoplan for Lausanne, shown here in 2010 after it was sold in the Romanian city of Ploieşti

A duo bus , also known as a bimodal bus or dual-mode bus , is a combination between a trolleybus and a motor bus . The Duo-Bus has - similar to a trolleybus with an additional combustion engine auxiliary drive or battery feed - two independent drives. This means that it can also run away from the overhead line infrastructure . In contrast to the auxiliary motor - which is rather weak relative to the main drive - in conventional trolleybuses, the second drive in duo buses functions as a fully-fledged alternative motor with similar or equally dimensioned power . In addition to the electric motor , it is usually a diesel engine with its own drive train , sometimes a diesel-electric drive without its own drive train. Since duo buses do not carry the electrical energy themselves, they are not hybrid buses according to the UNO definition . Depending on the mode of operation, they are either subject to the legal regulations for trolleybuses or those for buses, i.e. they are approved for both types of operation . Since around 2000, however, there has been an increasing trend towards using the auxiliary drive of trolleybuses also in regular passenger service, which largely made the duo bus less important.

prehistory

The All Service Vehicle in New Jersey and the two- vehicle vehicles in Basel, Lucerne, Oldenburg and Tétouan are regarded as the early forerunners of the duo bus . However, they have not yet been referred to as a duo bus.

The term duo bus was first used for the trolleybuses in Esslingen am Neckar for the trolleybuses with a powerful additional battery that were tested there from 1974 to 1981 , although these did not have two independent drives. However, this attempt was largely unsuccessful, which is why the first trolleybuses with an additional diesel drive went into operation in Esslingen as early as 1979. In the end, they were much more successful than their purely electric counterparts, whereupon the name Duo-Bus for this type of double drive became established.

advantages

With their catenary-independent secondary drive, duo buses can travel at the same speed as in electric mode and cover longer distances without any problems, i.e. with the same range as conventional buses. As a rule, duo buses serve lines that are not fully electrified without having to change trains. Some companies also use them as flexible reserve vehicles that can replace both trolleybuses and diesel buses.

The duo bus can thus use the advantages of the electric drive on expanded routes equipped with overhead lines and in city centers - that is, high acceleration, no exhaust emissions and low noise pollution - while it can flexibly operate almost any route on the outskirts and in the suburbs. In addition, the catenary network can be built step by step.

Another advantage is redundancy , which means that if the electrical system fails due to damage to the pantograph or a power failure, operation can continue. Trolleybus lines can also be extended at short notice to places where overhead lines have not yet been laid.

disadvantage

The concept of the duo buses with diesel drive also only partially fulfills the originally set expectations. A particular problem (as with the battery-operated duo buses) is the high vehicle weight - caused by carrying the alternative drive modules - and the associated increased energy consumption. In the Mercedes-Benz O 405 GTD , the electrical equipment alone weighs six tons.

The high acquisition costs , the more complex maintenance and the associated higher failure rate of these special vehicles also have negative effects on the profitability of duo buses . In contrast, the service life is shorter than that of a pure trolleybus. Another disadvantage is the greater space required by the technical equipment - this in turn sometimes leads to a lower transport capacity and is thus also at the expense of economy. Another disadvantage: every change in the type of traction is associated with a compulsory stay, this is at the expense of the turnaround time.

Operations companies

In 2018, duo buses will only be used on the Freiburg trolleybus (since 1987) and the Boston trolleybus (since 2004). Former Duo-Bus operations were:

Due to technical problems, numerous duo buses were taken out of service early or converted to pure trolleybuses or pure diesel buses. Some of these conversions were carried out as part of sales, especially because many second owners would not have been able to cope with the complicated technology or would not need it.

Type overview

Renault demonstration car during a test run in Seattle, June 1983

So far, 438 duo buses have been built as standard without the earlier forerunners mentioned above and the purely electrically operated Esslingen coaches. With the exception of three prototypes, these exclusively included articulated vehicles :

Manufacturer Years of construction Type Electrics number business Numbers
Breda 1988-1991 ADPB 350 AEG / Westinghouse 236 King County Metro, Seattle 5000 to 5235
Renault 1982-1984 PER 180 H 64 Demonstration cars: 2
Nancy : 48
St. Etienne : 8
Grenoble : 6		 Nancy: 603 to 650
Grenoble: 101 to 108
St. Etienne: 801 to 806
Daimler Benz 1986-1995 O 405 GTD AEG 47 various see main article
Neoplan 2004-2006 AN460LF Škoda 32 Massachusetts Bay Transportation Authority 1101 to 1132
Neoplan 1998 N 6121 Box 27 Transports publics de la region Lausanne 800 to 826
Volvo / Hess 1987-1989 B10M BBC-Sécheron / FIG 12 Freiburg transport company 501 to 512
MAN / Hess 2004 NGT 204 F Box 9 Freiburg transport company 513 to 521
Daimler Benz 1983 O 305 GTD AEG 4th various see main article
Daimler Benz 1979 O 305 D / E Bosch / Dornier 2 Trolleybus Esslingen am Neckar 303 and 304
Daimler Benz 1979 O 305 GD / E Bosch / Dornier 1 Trolleybus Esslingen am Neckar 305
MAN 1983 SG 240 H Duo Box 1 Essener Verkehrs-AG 3700
MAN / Voith 1984 SL 200 BBC Sécheron 1 Demonstration car / prototype no
Daimler Benz 1996 O 405 GNTD Kiepe / ZF 1 Zurich Transport Authority 51
Van Hool 1993 AG300TD Box 1 Arnhem trolleybus 5201

See also

literature

  • Erich Hoepke: Omnibuses in the traffic system of metropolitan areas . Planning, operation and control system - technology of buses, trolleybuses, duo buses and track buses. Expert, Renningen-Malmsheim 1995, ISBN 3-8169-1164-1 .

Web links

Commons : Duo-Bus  - collection of pictures, videos and audio files

Individual evidence

  1. ↑ Electrically charged for 66 years. Portrait of the Esslingen trolleybus in the Stuttgarter Zeitung on November 2, 2010