Multi-axle bus
Encyclopedia
Bus
A bus is a road vehicle designed to carry passengers. Buses can have a capacity as high as 300 passengers. The most common type of bus is the single-decker bus, with larger loads carried by double-decker buses and articulated buses, and smaller loads carried by midibuses and minibuses; coaches are...
or coach
Coach (vehicle)
A coach is a large motor vehicle, a type of bus, used for conveying passengers on excursions and on longer distance express coach scheduled transport between cities - or even between countries...
that has more than the conventional two axles, 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 bus
Trailer bus
A trailer bus or articulated trailer bus is a bus formed out of a bus bodied semi-trailer pulled by a conventional tractor unit in the same way as a conventional articulated semi-trailer truck....
es.
History
An early example of a multi-axle bus was a one-off three-axle CrossleyCrossley Motors
Crossley Motors was a British motor vehicle manufacturer based in Manchester, England. They produced approximately 19,000 high quality cars from 1904 until 1938, 5,500 buses from 1926 until 1958 and 21,000 goods and military vehicles from 1914 to 1945.Crossley Brothers, originally...
Condor, shown here, built for the 1932 Scottish Bus Show.
Reasons for multiple axles
Extra axles may also be provided on shorter buses 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
Tire
A tire or tyre is a ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by providing a flexible cushion that absorbs shock while keeping the wheel in close contact with the ground...
replacement, and to an extent, higher fuel consumption.
In some buses the rearmost axle is connected to the steering
Steering
Steering is the term applied to the collection of components, linkages, etc. which will allow a vessel or vehicle to follow the desired course...
, 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
Hong Kong
Hong Kong is one of two Special Administrative Regions of the People's Republic of China , the other being Macau. A city-state situated on China's south coast and enclosed by the Pearl River Delta and South China Sea, it is renowned for its expansive skyline and deep natural harbour...
and Singapore
Singapore
Singapore , officially the Republic of Singapore, is a Southeast Asian city-state off the southern tip of the Malay Peninsula, north of the equator. An island country made up of 63 islands, it is separated from Malaysia by the Straits of Johor to its north and from Indonesia's Riau Islands by the...
. Tri-axle buses also see high volume use in Dublin, Ireland. Imported tri-axle buses were used initially by Megabus
Megabus (United Kingdom)
Megabus is a UK coach service operated by Stagecoach Group. It started in 2003 and as of February 2010 operated 19 UK coach routes serving 41 destinations in England, Scotland and Wales. Some services link with Megatrain services which are also operated by Stagecoach...
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 Megabus
Megabus (United Kingdom)
Megabus is a UK coach service operated by Stagecoach Group. It started in 2003 and as of February 2010 operated 19 UK coach routes serving 41 destinations in England, Scotland and Wales. Some services link with Megatrain services which are also operated by Stagecoach...
.
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
Bedford VAL
The Bedford VAL was a type of coach chassis built by Bedford Vehicles 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 axles....
.
The Neoplan
Neoplan
NEOPLAN Bus GmbH is a German automotive company that manufactures buses, trolleybuses and coaches. NEOPLAN is now a subsidiary of NEOMAN Bus GmbH, which itself is a part of MAN SE.-Foundations:...
Megaliner was the first quad axle double decker coach, and is used in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
. Further examples include the Scania K380 8x2
Scania K-series
Scania K-series is a series of bus with longitudinally, straight-up mounted Euro IV engine at the rear. For the 5- and 6-cylinder engines Scania is using exhaust gas recirculation system to fulfill the legal Euro IV emission standard...
http://community.fotopic.net/search/simple.php?tab=P&txt=Scania+K380+8x2 .
Articulated chassis
Tri-axle is the standard arrangement of two part articulated busArticulated bus
An articulated bus is an articulated vehicle used in public transportation. It is usually a single-deck design, and comprises two rigid sections linked by a pivoting joint...
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
Neoplan Jumbocruiser
The NEOPLAN Jumbocruiser was an articulated double-deck multi-axle city coach built by NEOPLAN Bus GmbH between 1975 and 1992. At 18 meters in length, 2.50m wide and 4m in height, it is in the Guinness World Records as the world's largest bus with a capacity for 170 passengers.-History:The...
. Quad-axle arrangement is also the exclusive arrangement for three part bi-articulated bus
Bi-articulated bus
A bi-articulated bus or double articulated bus is an extension of an articulated bus in that it has three passenger compartment sections instead of two. This also involves the addition of an extra axle...
es.
A rare reason why a bus may have multiple axles is in the case of a trailer bus
Trailer bus
A trailer bus or articulated trailer bus is a bus formed out of a bus bodied semi-trailer pulled by a conventional tractor unit in the same way as a conventional articulated semi-trailer truck....
, where the bus passenger cabin is built as a body semi-trailer
Semi-trailer
A semi-trailer is a trailer without a front axle. A large proportion of its weight is supported by a road tractor, a detachable front axle assembly known as a dolly, or the tail of another trailer...
towed by a separate tractor unit
Tractor unit
A tractor unit, prime mover , road tractor, or traction unit is a heavy-duty commercial vehicle within the large goods vehicle category, usually with a large displacement diesel engine, and several axles. The tractor unit serves as a method of moving trailers...
.