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"Truck and trailer" redirects here. For the rugby tactic, see Playing rugby union#Maul. A typical passage of Rugby union takes the following form One team will initially gain possession of the ball either from the kick-off a restart kick or a set piece ( scrum
Tractor with end-dump semi-trailer
Tractor with end-dump semi-trailer
Semi-trailer truck with 'sleeper' behind the cab.
Semi-trailer truck with 'sleeper' behind the cab. A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with In American English a semi-trailer is a trailer without a front axle This article is about the semi-truck For the North American use of the word see Pickup truck.
A tractor with an auto-transport semi-trailer.
A tractor with an auto-transport semi-trailer. In American English a semi-trailer is a trailer without a front axle

A semi-trailer truck or tractor-trailer ( colloquially known as a transfer truck, 18-wheeler, semi, Diesel, Mack truck (although this is actually just one brand of truck maker), or big rig in the U.S., and transport in Canada; as a semi in Australia or New Zealand; and as an articulated lorry (artic) in the UK and Ireland) is an articulated truck or lorry consisting of a towing engine (tractor in the U. Mack Trucks is one of the world's leading Truck - Manufacturing companies. The United States of America —commonly referred to as the Country to "Dominion of Canada" or "Canadian Federation" or anything else please read the Talk Page For a topic outline on this subject see List of basic Australia topics. New Zealand is an Island country in the south-western Pacific Ocean comprising two main landmasses (the North Island and the South Island The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located Ireland (pronounced /ˈaɾlənd/ Éire) is the third largest island in Europe, and the twentieth-largest island in the world An articulated vehicle is a vehicle which has a permanent or semi-permanent pivoting joint in its construction allowing the vehicle to turn more sharply This article is about the semi-truck For the North American use of the word see Pickup truck. This article is about the semi-truck For the North American use of the word see Pickup truck. A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with S. , prime mover in Australia, and truck in the UK, Canada and New Zealand), and a semi-trailer (plus possible additional trailers) that carries the freight. In American English a semi-trailer is a trailer without a front axle A Trailer is generally an unpowered vehicle pulled by a powered vehicle

In the UK, the term juggernaut is sometimes used for articulated lorries. Please do not put information about the X-Men character on this page

Contents

Regional Configurations

North America

Tractor hauling tractors in Idaho
Tractor hauling tractors in Idaho
Rocky Mountain Double
Rocky Mountain Double

In North America, semi tractors usually have 3 axles, the front, or "steer", axle having two wheels, and each of the two rear, "drive", axles having a pair of "dualies" (double) wheels on each side. An axle is a central shaft for a rotating Wheel or Gear. In some cases the axle may be fixed in position with a bearing or Bushing Steering is the term applied to the collection of components linkages etc Thus, the most common configuration of tractor has 10 wheels. A smaller tractor having a single drive axle (six wheeler) is often used to pull shorter trailers in tight urban environments, such as downtown areas where a 60-foot rig would be too difficult to maneuver.

The cargo trailer usually has two "tandem" axles at the rear, each of which has dual wheels, or 8 wheels on the trailer. In American English a semi-trailer is a trailer without a front axle Tandem is a Latin Adverb meaning "at length" or "finally" Many trailers are equipped with moveable tandems that can be set to balance the weight of the trailer to stay within legal limits.

Although the cargo's weight added to the semi's weight can equal a certain amount of gross some roads are marked with a different gross restriction so the roads are not damaged. Cargos that exceed allowed weights are usually marked with overweight load and must obtain a permit to use certain roads. In the United States an oversize load is a truck tractor with an attached trailer with an over-dimensional object (the load on it

Rules governing the maximum size and weight of vehicles differ among states in the US. However, since the majority of hauling is done on the interstate system, the vast majority of trucks and trailer made in the US are built to the specifications of the Department of Transportation which governs the use of the interstate system. The D. O. T. has established vehicle limits of: 102 inches wide, 13. 5 feet in height, and 80,000 lbs gross weight. [2] These limits can be exceeded as individual states have the right to issue temporary oversize and/or overweight permits.

Trailer dimensions vary greatly depending on amount and type of cargo it was designed to haul. See types of trailers under Construction below.

Although dual wheels are most common, use of a single, wider tire (known as "super singles") on each axle is becoming popular, particularly among bulk cargo carriers and other weight-sensitive operators. This article is about tires used on road Vehicles including pneumatic tires and solid tires. The advantages of this configuration are dual: the lighter tire weight allows a truck to be loaded with more freight, and the single wheel covers less of the brake unit, which allows faster cooling. The biggest disadvantage is that when a tire becomes deflated or destroyed, it is not possible to drive the vehicle to a service location without risking damage to the rim, as it is with dual wheels. A wheel is a circular device that is capable of rotating on its axis facilitating movement or transportation whilst supporting a load ( Mass) or performing labour in machines

The United States also allows 2-axle tractors to tow two 1-axle 28. 5-foot (8. 7 m) semi-trailers known officially as STAA doubles and colloquially as doubles, a set, or a set of joints on all highways that are part of the National Network. The second trailer in a set of doubles uses a converter gear, also known as a con-gear. This apparatus supports the front half of the second trailer. Individual states may further allow longer vehicles (known as "longer combination vehicles" or LCVs), and may allow them to operate on roads other than those part of the National Network. A road train or roadtrain is a Trucking concept used in remote areas of Australia, the United States, and Western Canada to move

LCV types include:

Regulations on LCVs vary widely from state to state. No state allows more than three trailers without a special permit. The verb license or grant license means to give permission The noun license is the document demonstrating that permission Reasons for limiting the legal trailer configurations include both safety concerns and the impracticality of designing and constructing roads that can accommodate the larger wheelbase of these vehicles and the larger minimum turning radii associated with them. In both road and rail Vehicles the wheelbase is the distance between the centers of the front and rear wheels

Most states restrict operation of larger tandem trailer setups such as triple units, the "Turnpike Double" (twin 48-53 ft units) or the "Rocky Mountain Double. " (A full 48-53 ft unit and a shorter 28 ft unit) In general, these types of setups are restricted to tolled turnpikes such as I-80 through Ohio and Indiana, and select Western states. Contrary to the former article written on this topic, tandem setups are not restricted to certain roads anymore than a single setup. The exception are the units listed above. They are also not restricted because of weather or "difficulty" of operation.

The long-haul tractors used in interstate travel are often equipped with a "sleeper" behind the driver's cab, which can be anything from a small bunk to a rather elaborate miniature apartment. The cabin of a Truck, often simply called a cab, is an enclosed space in a truck where the driver is seated

Manufacturers used in the U. S.

These are for semi-trailer tractors, not straight, rigid, box or other heavy vehicles. This article is about the semi-truck For the North American use of the word see Pickup truck.

See also: List of dump truck manufacturers. The American Coleman was a Class 8 Semi truck. This one of a kind truck was built in the late 1960s Ford Motor Company is an American Multinational corporation and the world's fourth largest automaker based on Worldwide vehicle sales, following Kenworth is a Manufacturer of medium and Heavy-duty Class 8 Trucks based in Kirkland Washington, United States Navistar International Corporation ( (formerly International Harvester Company) is a manufacturer of International brand commercial trucks MaxxForce brand diesel Mack Trucks is one of the world's leading Truck - Manufacturing companies. Peterbilt Motors Company is a Manufacturer of medium- and heavy-duty Class 5 through Class 8 Trucks headquartered in Denton Texas Sterling Trucks is a manufacturer of heavy duty Trucks Sterling is a subsidiary of Freightliner LLC Portland Oregon. Volvo Trucks ( sv: Volvo Lastvagnar) a Swedish Truck manufacturer, owned by Volvo Group - AB Volvo, is the World's second largest Western Star Trucks is a Redford Township Michigan, United States based Manufacturer of Class 8 commercial Trucks Tractor units DAF CF 95 XF Davis Trailer & Equipment Hino Motors (Toyota Iveco Eurotrakker

Europe

The noticeable difference between tractor units in the U. A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with S. and Europe is that most European models are "cab over engine" (COE or forward control), while most U. The cabin of a Truck, often simply called a cab, is an enclosed space in a truck where the driver is seated Cab-over, also known as COE (Cab Over Engine cab forward, or forward control, is a body style of Truck or Van that has a vertical S. trucks are conventional (or normal control). For repairs, the entire cab hinges forward to allow maintenance access. European trucks, whether small rigid or fully articulated, have a sheer face on the front. This article is about the semi-truck For the North American use of the word see Pickup truck. An articulated vehicle is a vehicle which has a permanent or semi-permanent pivoting joint in its construction allowing the vehicle to turn more sharply This allows greater maneuverability, as the driver need only gauge distances behind his seating point, and this allows for shorter trucks with longer trailers (with larger freight capacity) within the legal maximum total length. In Europe the entire length of the vehicle is measured as total length, while in U. S. the cabin of the truck is normally not part of the measurement.

From 2006, 25. 25 m truck trailer combinations are to be allowed on restricted routes within Germany, following a similar (on-going) trial in The Netherlands. Like in Scandinavia, these vehicles in The Netherlands will run a 60 tonne weight limit. Two types are to be used: 1) a 26 tonne truck pulling a dolly and semi-trailer, or 2) an articulated tractor unit pulling two semi-trailers linked by a dolly. The UK government has so far decided not to have its own trial of these 60 tonne vehicles, but to keep an eye on the other countries' trials.

A truck pulling a trailer using a trailer dolly.
A truck pulling a trailer using a trailer dolly. A dolly that can be coupled to a Truck or trailer so as to support a Semi-trailer.

Using a dolly, which generally has to be equipped with lights and a license plate, rigid trucks can be used to pull semitrailers. A dolly that can be coupled to a Truck or trailer so as to support a Semi-trailer. A vehicle registration plate is a metal or plastic plate attached to a Motor vehicle or trailer for official identification purposes This article is about the semi-truck For the North American use of the word see Pickup truck. The dolly is equipped with a fifth wheel to which the trailer is coupled. The fifth wheel coupling provides the link between a Semi-trailer and the towing Truck, Tractor unit, leading trailer or dolly. Because the dolly attaches to a pintle hitch on the truck, maneuvering a trailer hooked to a dolly is different from maneuvering a fifth wheel trailer. A pintle is a pin or bolt usually inserted into a Gudgeon, which is used as part of a pivot or hinge Backing the vehicle requires same technique as backing an ordinary truck/full trailer combination, though the dolly/semi setup is probably longer, thus requiring more space for maneuvering. Reversing (also known as backing up) is the process of Driving a Vehicle in the reverse direction in order to maneuver The tractor-semitrailer configuration is rarely used on timber trucks, since these will use the two big advantages of having the weight of the load on the drive wheels, and the loader crane used to lift the logs from the ground can be mounted on the rear of the truck behind the load, allowing a short (lightweight) crane to reach both ends of the vehicle without uncoupling. Lumber or timber is Wood in any of its stages from felling through readiness for use as structural Material for Construction, or A crane is a lifting machine equipped with a Winder, Wire ropes or Chains and sheaves that can be used both to lift and lower materials and to Lumber or timber is Wood in any of its stages from felling through readiness for use as structural Material for Construction, or Also construction trucks are more often seen in a rigid + midaxle trailer configuration instead of the tractor + semitrailer setup.

The largest trailer manufacturer in Europe is Schmitz Cargobull. Schmitz Cargobull, founded in 1892 is the leading manufacturer of tippers trailers and Semi-trailers for commercial vehicles in Europe

In continental Europe, most semi tractors have two axles, again with the front, steer, having two wheels, and rear, drive, having twin wheels on each side. Thus, the most common configuration has six wheels. The cargo trailer usually has three axles at the rear, with single wheels, or six wheels in total. The entire vehicle thus usually has five axles and 12 wheels in total, although the trailers can vary in number of wheels.

Sweden and Finland

In Sweden the allowed length is 24 metres (78. "Sverige" redirects here For other uses see Sweden (disambiguation and Sverige (disambiguation. 7 ft) for all vehicles and 25. 25 metres (82. 8 ft) for trucks with two trailers. In 1997 the rules were changed, following the European Economic Area rules, allowing trucks to pull two trailers with a total length of 25. The European Economic Area ( EEA) came into being on 1 January 1994 following an agreement between member states of European Free Trade Association (EFTAthe 25 metres (82. 8 ft), assuming certain conditions were met, like ABS on all vehicles. An anti-lock braking system, or ABS (from the German, A nti' b' lockier' s' ystem) is a safety system on Motor vehicles In Finland most trucks can tow any trailer as long as total length stays within 25. Finland, officially the Republic of Finland ( is a Nordic country situated in the Fennoscandian region of northern Europe. 25 metres (82. 8 ft). The exception to this is a tractor unit pulling a semi-trailer, which can be only 16. 5 metres (54. 1 ft) long. The allowed gross weight in both countries is up to 60 tonnes (132,277 lb) depending on the distance between the first and last axle. In Sweden the old style tractor-trailer is still the most common, but in some areas, especially container haulage, 25. 25 metre (82. 8 ft) vehicles are available. In Finland most new trucks and trailers are built with 25. 25 metre (82. 8 ft) in mind.

An articulated lorry (Renault Magnum) in London, England.
An articulated lorry (Renault Magnum) in London, England. An articulated vehicle is a vehicle which has a permanent or semi-permanent pivoting joint in its construction allowing the vehicle to turn more sharply

UK

In the UK, to carry the maximum permitted gross weight of 44 tonnes, both tractor and semi-trailer must have 3 or more axles each [3]. The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom, the UK or Britain,is a Sovereign state located In the Physical sciences weight is a Measurement of the gravitational Force acting on an object In practice, there is no legal height limit; however, bridges over 16. 5 ft (5. 03 m) do not have the height marked on them. No heavier vehicles are permitted on the UK road network, except for indivisible loads which would be classed as abnormal (or oversize); these vehicles are required to display an STGO (Special Types General Order) plate on the front of the prime mover and, under certain circumstances, are required to travel by an authorised route and have an escort. A road is an identifiable route, way or path between two or more places.

In the UK some articulated trucks have 8 tyres on 3 axles on the tractor these are known as 6 wheelers or "6 leggers" , with either the centre or rear axle having single wheels which normally steer as well as the front axle and can be raised when not needed (i. e. when unloaded or only a light load is being carried; an arrangement known as a TAG axle), while some trailers have 2 axles which have twin wheels on each axle, and other trailers with 3 axles of which 1 axle can be a TAG axle which have super-single wheels; In the UK, two wheels bolted to the same hub are classed as a single wheel, therefore a standard six-axle articulated truck is considered to have twelve wheels, even though it has twenty tyres. The UK also allows artic truck tractors which have 6 tyres on 2 axles; these are known as 4 wheelers.

Articulated lorrys with extended tents, representing Renault at Silverstone.
Articulated lorrys with extended tents, representing Renault at Silverstone. A tent is a shelter consisting of sheets of fabric or other material draped over or attached to a frame of poles or attached to a supporting rope This is about the company for other uses see Renault (disambiguation. Silverstone Circuit is a Motor racing circuit in Northamptonshire and Buckinghamshire, named after the village in the former England

Most [UK] trailers are 45 feet (13. 5 meters) long and, dependent on the position of the fifth wheel and kingpin, a coupled tractor unit and trailer will have a combined length of between 50 and 55 feet (15. The fifth wheel coupling provides the link between a Semi-trailer and the towing Truck, Tractor unit, leading trailer or dolly. 25 and 16. 75 meters). Although the Construction and Use Regulations allow a maximum rigid length of 60 feet (18. 2 meters), this combined with a shallow kingpin and fifth wheel set close to the rear of the tractor unit can give an overall length of around 75 feet (22. 75 meters), although combinations of this length are usually used only to carry steel or concrete beams. Providing certain requirements are fulfilled, a Special Types General Order (STGO) allows for vehicles of any size or weight to travel on UK roads. However, in practice any such vehicle has to travel by a route authorised by the Department of Transport and move under escort. The escort of abnormal loads in the UK is now predominantly carried out by private companies, but extremely large or heavy loads that require road closures must still be escorted by the police.

Australia

Main article: Road transport in Australia
an Australian prime mover Kenworth and B double trailer combination
an Australian prime mover Kenworth and B double trailer combination
A road train in Australia.
A road train in Australia. Road transport is an essential element of Transport in Australia due to the large land area of the country and low population density in considerable parts of the country A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with Kenworth is a Manufacturer of medium and Heavy-duty Class 8 Trucks based in Kirkland Washington, United States A road train or roadtrain is a Trucking concept used in remote areas of Australia, the United States, and Western Canada to move

Australian road transport has a reputation for using very large trucks and road trains. For a topic outline on this subject see List of basic Australia topics. This is reflected in the most popular configurations of trucks generally having dual drive axles and three axles on the trailers, with 4 tires on each axle. This means that Australian single semi-trailer trucks will usually have 22 wheels which is generally more than their counterparts in other countries. Long haul transport usually operates as B-doubles with two trailers (each with three axles), for a total of nine axles (including steering).

From July 2007 the Australian Federal and State Governments allowed the introduction of B-triple trucks on a specified network of roads[1]. B-Triples are set up differently to conventional road trains. The front of their first trailer is supported by the turntable on the prime mover. The fifth wheel coupling provides the link between a Semi-trailer and the towing Truck, Tractor unit, leading trailer or dolly. The second and third trailers are supported by turntables on the trailers in front of them. As a result, B-Triples are much more stable than road trains and handle exceptionally well. True road trains only operate in remote areas, regulated by each state or territory government.

In total, the maximum length that any articulated vehicle may be (without a special permit and escort) is 53. 5 metres (175. 5 ft), its maximum load may be up to 164 tonnes (361,558 lb) gross and may have up to 4 trailers. However, heavy restrictions apply to the areas where such a vehicle may travel in most states. In remote areas such as the Northern Territory great care must be taken when sharing the road with longer articulated vehicles that often travel during the day time, especially 4 trailer road trains. The Northern Territory is a federal territory of Australia, occupying much of the center of the mainland continent as well as the central northern regions

B-double truck on the Sturt Highway
B-double truck on the Sturt Highway

In most areas a truck is generally limited to two trailers and a total length of 26 metres (85 ft) and in urban areas this length limit is further reduced to 19 metres (62 ft). The Sturt Highway is an Australian Highway in New South Wales, Victoria, and South Australia. 25 metre (82 ft), 62. 5 tonne (137,788 lb) B-doubles are very common in all parts of Australia including state capitals and on major routes may outnumber single trailer configurations.

In Australia, both conventional tractor units and cabovers are common, however cabovers are most often seen on B-Doubles on the eastern seaboard where the reduction in total length allows the vehicle to pull longer trailers and thus more cargo than it would otherwise. Cab-over, also known as COE (Cab Over Engine cab forward, or forward control, is a body style of Truck or Van that has a vertical

Super single tires are sometimes used on tri-axle trailers. The suspension is designed with travel limiting, which will hold the rim off the road for one blown or deflated tire for each side of the trailer, so a trailer can be driven at reduced speed to a safe place for repair. Super singles are also often used on the steer axle in Australia to allow greater loading over the steer axle. The increase in loading of steer tires requires a permit.

Construction

Types of trailers

There are many types of semi-trailers in use, designed to haul a wide range of products. See Semi-trailer for more detail. In American English a semi-trailer is a trailer without a front axle

Coupling and uncoupling

The cargo trailer is, by means of a nipple called the king pin, hooked to a horseshoe-shaped quick-release coupling device called a fifth wheel at the rear of the towing engine that allows easy hook up and release. bus trailer A Trailer bus or articulated trailer bus is a Bus formed out of a bus bodied Semi-trailer pulled by a conventional Tractor unit A refrigerated container or reefer is a shipping container used in Intermodal freight transport that is refrigerated for the transportation of A refrigerator truck is a Van Truck designed to carry perishable freight at specific low temperatures A tank truck ( United States usage or tanker lorry ( United Kingdom usage is a Motor vehicle designed to carry liquefied loads, The kingpin is the main Pivot in the steering mechanism of a car or other Vehicle. The fifth wheel coupling provides the link between a Semi-trailer and the towing Truck, Tractor unit, leading trailer or dolly. A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with The truck trailer cannot move by itself because it only has wheels at the rear end, hence the name semi-trailer: it only carries half its own weight. A Trailer is generally an unpowered vehicle pulled by a powered vehicle The vehicle has a tendency to fold at the pivot point between the semi and the trailer when braking hard at high speeds. Such a truck accident is called a jack-knife, or jackknifing. Jackknifing means the accidental folding of an Articulated vehicle (i

Braking

Semi trucks use air pressure, rather than hydraulic fluid, to actuate the brakes. For the mechanical technology see Hydraulic machinery and Hydraulic cylinder Hydraulics is a topic of science and Engineering A brake is a device for slowing or stopping the motion of a Machine or Vehicle, or alternatively a device to restrain it from starting to move again This allows for ease of coupling and uncoupling of trailers from the tractor unit, as well as reducing the potential for problems common to hydraulic systems, such as leakage or "brake fade" caused when overheated brake fluid vaporizes in the hydraulic lines. (Brake fade may also occur when the lining of the braking unit becomes severely overheated. This has no connection to the fluid lines. )

The "parking brake" of the tractor unit and the "emergency brakes" of the trailer are spring brakes that require air pressure in order to be released. They are applied when air pressure is released from the system, and disengaged when air pressure is supplied. This is an emergency feature which ensures that if air pressure to either unit is lost, that unit will not lose all braking capacity and become uncontrollable.

The trailer controls are coupled to the tractor through two "glad-hand" connectors, which provide air pressure, and an electrical cable, which provides power to the lights and any specialized features of the trailer.

"Glad-hand" connectors (also known as "palm couplings,") are air hose connectors, each of which has a flat engaging face and retaining tabs. The faces are placed together, and the units are rotated so that the tabs engage each other to hold the connectors together. This arrangement provides a secure connection, but allows the couplers to break away without damaging the equipment if they are pulled, as may happen when the tractor and trailer are separated without first uncoupling the air lines. These connectors are similar in design to the ones used for a similar purpose between railroad cars. Two air lines control the trailer unit. An "emergency" or main air supply line pressurizes the trailer's air tank and disengages the emergency brake, and a second "service" line controls the brake application.

In the UK male/female quick release connectors "red line" or emergency, have a female on the truck and male on the trailer and a "yellow line" or service has a male on the truck and female on the trailer. This avoids coupling errors (causing no brakes) plus the connections will not come apart if pulled by accident. The three electrical lines will fit one way round a primary "black" a secondary "green" and an ABS lead, all of these lines are collectively known as "suzies"

Another braking feature of semi-trucks is the engine brake, "Retarder," or "Jacobs brake" (usually shortened to "Jake brake"). Engine braking is the act of using the energy-requiring compression stroke of the Internal combustion engine to dissipate energy and slow down a vehicle JAKE BRAKE is a trademark for vehicle retarding systems or Engine brakes developed and manufactured by Jacobs Vehicle Systems Inc This feature controls hydraulic actuators on the exhaust valves of the truck's diesel engine. When activated, the actuators hold the valves slightly open, virtually turning the engine into a giant compressor. However, it produces a loud and distinctive exhaust note, and owing to noise concerns, some locales have prohibited or restricted the use of engine brake systems inside their jurisdictions, particularly in residential areas. The advantage to using this instead of conventional brakes is that a truck can travel down a long grade without overheating its wheel brakes.

Transmission

Because of the wide variety of loads the semi may carry, they usually have a manual transmission to allow the driver to have as much control as possible. A manual transmission (also known as a stick shift or just 'stick' 'straight drive' or standard transmission) is a type of transmission used in However, all US truck manufacturers now offer fully automatic transmissions. An automatic transmission (commonly "AT" or "Auto" is an Automobile Gearbox that can change Gear ratios automatically as the vehicle

Since engine efficiency is a requirement and high acceleration is not, semi truck transmissions usually provide at least nine or ten gear ratios, but possibly as many as eighteen (e. g. Australian Road Trains). A road train or roadtrain is a Trucking concept used in remote areas of Australia, the United States, and Western Canada to move A large number of transmission ratios means the engine itself can operate within a narrow range of speeds. The range of speeds over which an engine is expected to perform well has implications for the design - the narrower the range, the more the engine can be optimised for that. Also having so many gears allows fine-grained control of engine braking for better control on downhills and in curves.

A ten speed manual transmission is controlled via a six-slot H-Box pattern similar to that in five-speed cars - five forward and one reverse gear. Gears six to ten (and high speed reverse) are accessed by toggling a selector control - so that first gear becomes sixth, second becomes seventh, etc.

Another difference between semi-trucks and cars is the way the clutch is set up. On a regular car the clutch is put to the floor for every gear shift to ensure the gearbox is free from the engine. On a semi-truck this is not so because there is the clutch brake. Because the clutch and gearbox is so large the gears will spin freely after the clutch is put in at a stop. This will cause grinding when putting it in gear. The clutch brake stops the rotation of the gears and allows the truck to be put into gear without grinding. The very bottom of the clutch is where the clutch brake activates as a result shallow clutching is always used on a semi-truck.

Lights

An electrical connection is made between the tractor and the trailer through a cable often referred to as a "pigtail. " This cable is a bundle of wires in a single casing. Each wire controls one of the electrical circuits on the trailer, such as running lights, brake lights, turn signals, etc. A standard cable would break when the rig went around corners so it is coiled and retains these coils when not under tension. It is these coils that cause the cable to look like a pigtail.

In most countries a trailer or semi-trailer must have minimum

Drivers license

A special driver's license is required to operate various commercial vehicles. A driver's license, driver license, driver licence, or driving licence is an official document which states that a person may operate a

Canada

Regulations vary by province. A license to operate a vehicle with air brakes is required, normally a Class I commercial license. In Ontario, a "Z" endorsement [4] is required. Ontario (ɒnˈtɛrioʊ is a province located in the central part of Canada, the largest by population and second largest after Quebec Anyone holding an Ontario "Z" endorsement can drive a heavy truck with up to one towed vehicle, weighing no more than 4. 6 metric tons if he or she also holds a Class A (tractor-trailer), B (school bus), C (regular bus) or D (heavy trucks other than tractor trailers) licence. This article is about the tonne or metric ton For other tons see Ton. [5] Anyone holding an Ontario Class A licence or equivalent can drive a tractor-trailer combination with at least 2 towed vehicles (Ibid. ).
In Manitoba, one requires a class 1 license, with an "A" or "S" endorsement to operate a semi-truck. Manitoba (English ˌmænɨˈtoʊbə French /manitoba/ is a province of Canada, spanning 647797 square kilometres (250116  sq mi of North America An "A" endorsement is for air brakes, and an "S" endorsement is operation of air brakes, plus adjustment of them.

United States

Drivers of semi-trailer trucks generally require a Class A commercial driver's license to operate any combination vehicles with a Gross Vehicle Weight Rating (or GVWR) in excess of 26,000 pounds (11. A commercial driver's license ( CDL) is required in the United States to operate any type of vehicle with a gross weight of 26001 lb (11793 kg or over including A gross vehicle weight rating ( GVWR) is the maximum allowable total Weight of a Road Vehicle or trailer when loaded - i 8 t). Some states (such as North Dakota) provide exemptions for farmers, allowing non-commercial license holders to operate semis within a certain range of their farm within the state. North Dakota ( is a state located in the Midwestern and Western regions of the United States of America. Also a person under the age of 21 cannot operate a commercial vehicle outside the state where the commercial license was issued. A person must be at least 18 in order to be issued a commercial license.

In addition, Endorsements are necessary for certain cargo and vehicle arrangements and types;

Taiwan

Taiwanese sign prohibiting heavy trailers
Taiwanese sign prohibiting heavy trailers

The Road Traffic Security Rules (zh:道路交通安全規則) require a combination vehicle driver license (traditional Chinese: 聯結車駕駛執照) to drive a combination vehicle (traditional Chinese: 聯結車). These rules define a combination vehicle as a motor vehicle towing a heavy trailer, i. e. , a trailer with a gross weight of more than 750 kilograms (1,653 lb).

European Union

A category C+E driver's license is required to drive an articulated lorry. A driver's license, driver license, driver licence, or driving licence is an official document which states that a person may operate a

Australia

Truck drivers in Australia require an endorsed license. These endorsements are gained through training and experience. The minimum age to hold an endorsed license is 18 years, and/or must have held open (full) driver's license for minimum 12 months. The following are the heavy vehicle license classes in Australia:

New Zealand

In New Zealand drivers of heavy vehicles require specific licenses, termed as 'classes'. A Class 1 Drivers License (aka a Car License) will allow the driving of any vehicle with Gross Laden Weight (GLW) or Gross Combination Weight (GCW) of 4500kg or less. For other types of vehicles the Classes are separately licensed as follows:

Further information on the New Zealand Licensing system for Heavy Vehicles can be found at Land Transport New Zealand.

Role in industry

Main article: dump truck

Modern day semi-trailer trucks often operate as a part of a domestic or international transport infrastructure to support containerized cargo shipment. A dump truck or production truck is a Truck used for transporting loose material (such as Sand, Gravel, or dirt) for Construction In American English a semi-trailer is a trailer without a front axle This article is about the semi-truck For the North American use of the word see Pickup truck. Transport or transportation is the movement of people and goods from one place to another Containerization (or containerisation) is a system of Intermodal freight transport Cargo Transport using standard ISO containers Cargo (or freight) refers to goods or produce transported generally for Commercial gain by ship, aircraft, train, Shipping is physical process of Transporting goods and Cargo. Various types of rail flat bed train cars are modified to hold the cargo trailer or container with wheels or without. A flatcar (also flat car) is a piece of Railroad rolling stock that consists of an open flat deck on four or six wheels or a pair of trucks (US or This is called "Intermodal" or "piggy-back" or "piggyback". Intermodal freight transport involves the transportation of freight in a container or Vehicle, using multiple modes of Transportation ( Something that is piggy-backed (archaically known as pickaback) is something that is riding on the back of something else The system allows the cargo to switch from the highway to railway or vice versa with relative ease by using gantry cranes. A crane is a lifting machine equipped with a Winder, Wire ropes or Chains and sheaves that can be used both to lift and lower materials and to

The large trailers pulled by a tractor unit come in many styles, lengths, and shapes. A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with Some common types are: vans, reefers, flatbeds, sidelifts and tankers. These trailers may be refrigerated, heated, ventilated, or pressurized, depending on climate and cargo. Some trailers have movable wheel axles that can be adjusted by moving them on a track underneath the trailer body and securing them in place with large pins. The purpose of this is to help adjust weight distribution over the various axles, to comply with local laws.

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  1. ^ [1] Press release: VAILE ANNOUNCES THE B-TRIPLE ROAD NETWORK
Air brakes are used in Trucks Buses trailers, and Semi-trailers. An articulated vehicle is a vehicle which has a permanent or semi-permanent pivoting joint in its construction allowing the vehicle to turn more sharply A brake is a device for slowing or stopping the motion of a Machine or Vehicle, or alternatively a device to restrain it from starting to move again A dolly that can be coupled to a Truck or trailer so as to support a Semi-trailer. Drayage originally meant "to transport by a sideless cart" A dump truck or production truck is a Truck used for transporting loose material (such as Sand, Gravel, or dirt) for Construction A hybrid vehicle is a vehicle that uses two or more distinct power sources to propel the vehicle Containerization (or containerisation) is a system of Intermodal freight transport Cargo Transport using standard ISO containers Jackknifing means the accidental folding of an Articulated vehicle (i A crane is a lifting machine equipped with a Winder, Wire ropes or Chains and sheaves that can be used both to lift and lower materials and to In the United States an oversize load is a truck tractor with an attached trailer with an over-dimensional object (the load on it A refrigerator truck is a Van Truck designed to carry perishable freight at specific low temperatures A road train or roadtrain is a Trucking concept used in remote areas of Australia, the United States, and Western Canada to move In American English a semi-trailer is a trailer without a front axle A tank truck ( United States usage or tanker lorry ( United Kingdom usage is a Motor vehicle designed to carry liquefied loads, A tractor unit, traction unit, road tractor or prime mover ( Australian English) is a Heavy-duty Vehicle, usually with A Trailer is generally an unpowered vehicle pulled by a powered vehicle bus trailer A Trailer bus or articulated trailer bus is a Bus formed out of a bus bodied Semi-trailer pulled by a conventional Tractor unit A train is a connected series of vehicles that move along a track ( Permanent way) to transport freight or passengers from one place to another This article is about the semi-truck For the North American use of the word see Pickup truck. A truck driver (Commonly called a trucker, driver or Teamster in the United States and Canada, a truckie or
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