Neoplan Doppelstockbus Viernheim 100 3625

A multi-axle bus is a

bus A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a road vehicle that carries significantly more passengers than an average car or van. It is most commonly used in public transport, but is also in use for cha ...

coach Coach may refer to: Guidance/instruction * Coach (sport), a director of athletes' training and activities * Coaching, the practice of guiding an individual through a process ** Acting coach, a teacher who trains performers Transportation * Co ...

that has more than the conventional two

axle An axle or axletree is a central shaft for a rotating wheel or gear. On wheeled vehicles, the axle may be fixed to the wheels, rotating with them, or fixed to the vehicle, with the wheels rotating around the axle. In the former case, bearing ...

s (known as a twin-axle bus), usually three (known as a tri-axle bus), or more rarely, four (known as a quad-axle bus). Extra axles are usually added for legal weight restriction reasons, or to accommodate different vehicle designs such as articulation, or rarely, to implement trailer buses.

History

An early example of a multi-axle bus was a one-off three-axle

Crossley Crossley, based in Manchester, United Kingdom, was a pioneering company in the production of internal combustion engines. Since 1988 it has been part of the Rolls-Royce Power Engineering group. More than 100,000 Crossley oil and gas engines ...

Condor, show
here
built for the 1932 Scottish Bus Show.

Reasons for multiple axles

Usually vehicle licensing authorities of different countries will set legal limits on the amount of weight that can be put on each axle. In the UK, a recent extension to the legal limit on the length of rigid buses and coaches has led to the increased use of three axles to accommodate the heavier chassis and passenger load. Certain countries apply exceptions to vehicle rules for specific operations. Extra axles may also be provided on shorter

es and coaches to accommodate extra equipment loads, such as passenger lifts, or comforts such as toilets, televisions, climate controls. In addition, in some cases the need is bus cargo transport, when large cargo compartments and heavy weight of cargo needs extra axles. Adding axles to chassis designs is done for specific reasons such as weight or legalities, as having extra axles means extra costs for the operator in terms of tyre replacement, and to an extent, higher

fuel consumption A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy or to be used for work. The concept was originally applied solely to those materials capable of releasing chemical energy but ...

Rear axle steering

In some buses the rearmost axle is connected to the steering, with the rear most set steering in the opposite direction to the front axle. This steering arrangement makes it possible for the longer triple axle buses to negotiate corners with greater ease than would otherwise be the case.

Rigid chassis

Tri-axle double-decker buses are common in high capacity operating environments where articulated buses are not used, such as Hong Kong and Singapore. Tri-axle buses also see high volume use in

Dublin, Ireland Dublin (; , or ) is the capital and largest city of Ireland. On a bay at the mouth of the River Liffey, it is in the province of Leinster, bordered on the south by the Dublin Mountains, a part of the Wicklow Mountains range. At the 2016 cen ...

. Imported tri-axle buses were used initially by

Megabus Megabus may refer to: *Megabus (Europe), a low-cost coach service with services in Europe owned by ComfortDelGro. *Megabus (North America) Megabus, branded as megabus.com, is an intercity bus service of Coach USA/Coach Canada operating in the eas ...

for high capacity low cost intercity travel in the UK. Tri-axle double decker coaches have been used to accommodate the extra weight. Models are also being introduced on high capacity inter-city routes, such as by the operator

. A twin steer coach is a rare type of tri-axled coach; where the double axles are in the front and steer, as in the

Bedford VAL The Bedford VAL is a type of coach chassis that was built by Bedford in the United Kingdom from the mid-1960s to the early 1970s. It was unusual at the time for its multi-axle design, in a " chinese six" wheelplan, i.e. with two front steering ...

or Bustech CDi. The Neoplan Megaliner was the first quad axle double decker coach, and is used in

Japan Japan ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the north ...

. Further examples include the Scania K380IB 8x2.

Articulated chassis

Tri-axle is the standard arrangement of two part

articulated bus An articulated bus, also referred to as a banana bus, bendy bus, tandem bus, vestibule bus, wiggle wagon, stretch bus, or an accordion bus, (either a motor bus or trolleybus) is an articulated vehicle used in public transportation. It is usua ...

es. Quad-axle arrangement is sometimes employed on articulated buses to accommodate the extra weight of coach bodies, such as in this quad axle articulated coach''
Volvo Articulated Coach
and the quad axle double deck articulated coach, the Neoplan Jumbocruiser. Quad-axle arrangement is also the exclusive arrangement for three part bi-articulated buses. A rare reason why a bus may have multiple axles is in the case of a trailer bus, where the bus passenger cabin is built as a body semi-trailer towed by a separate tractor unit.

References

External links

{{buses Buses by type