 semi-trailer truck with 'sleeper' behind the cab. A semi-trailer truck or tractor-trailer (colloquially known as an 18-wheeler, semi or big-rig in the US, as a semi in Australia, US, and Canada, and as an articulated lorry or artic in the UK and Ireland) is an articulated truck consisting of a towing engine (tractor in the US, prime mover in Australia), and a trailer that carries the freight. (See below for the etymology of the name "semi-trailer"). http://landsat. ...
http://landsat. ...
The driver of this DAF tractor with an auto-transport semi-trailer prepares to offload Skoda Octavia cars in Cardiff, Wales For further uses of the word truck, see Truck (disambiguation). ...
...
The driver of this DAF tractor with an auto-transport semi-trailer prepares to offload Skoda Octavia cars in Cardiff, Wales For further uses of the word truck, see Truck (disambiguation). ...
A Trailer is an unpowered vehicle pulled by one with an engine. ...
Regional Configurations
United States In United States, 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 "dual" (double) wheels on each side. Thus, the most common configuration of tractor has 10 wheels. The cargo trailer usually has two "tandem" axles at the rear, each of which has dual wheels, or 8 wheels on the trailer. An axle is a central shaft for a rotating wheel or gear. ...
Steering is the term applied to the collection of components, linkages, etc. ...
Although dual wheels are most common, use of a single, wider tire on each axle is becoming increasingly popular, particularly among bulk cargo carriers and other weight-sensitive operators. The advantages of this configuration are two: The lighter weight allows a truck to be loaded with more weight of product, 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.
However, the United States also allows 2-axle tractors to tow two 1-axle 28-foot (8.5 m) semi-trailers known colloquially as doubles, a set, or a set of joints. Some states also allow towing up to three 28-foot trailers known coloquially as triples. A 2-axle full-sized semi-trailer pulling a 28-foot "pup" trailer known as a Rocky Mountain Double is also permitted in some regions. Very few states allow two full-sized semi trailers which are similar to the Australian road trains.
Europe
 An articulated lorry (Renault Magnum) in London, England. In Europe, most semi tractors have 2 axles, again with the front, steer, having two wheels, and rear, drive, having a pair of double wheels on each side. Thus, the most common configuration has 6 wheels. Conversely, the cargo trailer usually has three axles at the rear, with single wheels, or 6 wheels in total. One way or the other, the entire vehicle thus usually has 5 axles and 12 wheels in total, although the trailers can vary in number of wheels. Overall lengths often range from 50 to 70 ft (15 to 25 m) in the US, and most US states limit the overall weight to 80,000 lb (36 tonne) The long-haul towing engines 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. An articulated lorry in London, England. ...
An articulated lorry in London, England. ...
World map showing location of Europe When considered a continent, Europe is the worlds second-smallest continent in terms of area, with an area of 10,600,000 km² (4,140,625 square miles), making it larger than Australia only. ...
Cargo is a term used to denotes goods or produce being transported generally for commercial gain, usually on a ship, plane, train or lorry. ...
A foot (plural: feet) is a non-SI unit of distance or length, measuring around a third of a metre. ...
The metre, or meter, is the basic unit of length in the International System of Units (SI: Système International dUnités). ...
The pound is the name of a number of units of mass or weight, all in the range of 300 to 600 grams. ...
A tonne, sometimes known as metric ton in American English, (symbol t) is a unit of mass. ...
An apartment (or flat) is a self-contained housing unit that occupies only part of a building. ...
The noticeable difference between trucks in the US and lorries in Europe is the lack of a nose on European models. While some US trucks are built without a nose, they are not as common. In European design, the driver's cab is positioned above the engine. For repairs, the entire cab hinges forward to allow maintenance access. European lorries, whether small or fully articulated, have a sheer face on the front. This allows greater manoeuvrability when steering, 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 US the cabin of the truck is normally not part of the measurement.
Sweden  The most common truck-trailer in Sweden. In Sweden the allowed length is 24 meters for all vehicles and 25.25 meters for trucks with two trailers. The allowed gross weight is up to 60 metric tons depending on the distance between the first and last axle. In 1997 the rules were changed, under pressure from the EU, allowing trucks to pull two trailers with a total length of 25.25 meters, assuming certain conditions were met, like ABS on all vehicles. The old style tractor-trailer is still the most common overall, but in some areas, especially container haulage, 25.25 meter vehicles are coming strong. ABS is a TLA (acronym) for: ADULT BOOK STORE Anti-lock braking system Acrylonitrile butadiene styrene, a plastic Australian Bureau of Statistics, Australias official statistical organization American Bureau of Shipping American Bible Society Anchor Bible Series Asset-backed security Automatic Beam System - automated railways & monorails Albino Black Sheep - website...
A truck pulling a trailer using a dolly. Using a dolly, which has to be equipped with lights and a license plate, rigid trucks can be used to pull regular trailers. The dolly and trailer together act like a regular trailer, so driving it and backing up is no different.  A truck with two trailers carrying one 20ft and one 40ft container. The old truck-trailer configuration is almost the only style used on timber trucks. There are at least two big advantages with this, one is the weight of the load on the drive wheels, and two, that the crane used to lift the logs from the ground can be mounted on the rear of the truck behind the load, instead of behind the cab which would make it difficult to reach to the end of the trailer.
Construction The cargo trailer is hooked to a horseshoe-shaped coupling device called a fifth wheel at the rear of the towing engine that allows easy hook up and release. The 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. 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 appropriately called a jack-knife, or jack-knifing.
Semi trucks use air pressure, rather than hydraulic fluid to actuate the brakes. 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.) A brake is a device for slowing or stopping the motion of a machine, and to keep it from starting to move. ...
The "parking brake" of the tractor unit and the "emergency brake" of the trailer are applied when air pressure is released, 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 are air couplers, 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 when they are pulled, as may happen when the tractor and trailer are separated without first uncoupling the air lines.
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.
Another braking feature of semi-trucks is the "engine brake", colloquially known as the "Jake brake". This feature uses the engine to slow the vehicle, which allows trucks to travel down long grades without overheating their wheel brakes.
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 special driver's license is required to operate a semi-trailer in most countries.
Road Trains
 Road train, Australia. This one travels from the port city of Darwin to the tourist centre of Alice Springs. In Australia, semi-trailers with more than one trailer are known as road trains. In certain areas "B-doubles" are permitted. These include a modified trailer with a turntable at the rear to allow a second trailer to be tightly coupled to the rig without the extra cost and handling problems of a dolly. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...
Darwin is the capital city of the Northern Territory, and is a city of 109,420 people (2001 Australian Census), on Australias far north-western coastline. ...
Alice Springs on a large scale map Alice Springs is a large town in the Northern Territory of Australia located at 23°42′ S 133°52′ E. Its population of 28,178 (2001 Census) makes it the second-largest settlement in the Territory (the only other towns of significant size...
Most road trains transport cattle on the long gravel beef roads of the isolated interior. ...
On some interstate highways in the US, long-haul semi-trailer trucks can tow another full trailer at the end, which makes the vehicle look like a two-car small train. Some of the second cars are full trailers with wheels on both ends, while others are just regular semi-trailer cars hooked to the standard coupling device on another set of wheels in tow (sometimes referred to as a "dolly"). Some states further allow a third trailer to be added to the vehicle, against the objections of some car drivers who must share the highways with these longer trucks.
Role in Industry Modern day semi-trailer trucks often operate as a part of an international transport infrastructure to support containerized cargo shipment. Some flat bed train cars are modified to hold the cargo trailer with wheels and all. This is called "piggy-back" in North America. The system allows the cargo to switch from the highway to railway or vice versa with ease. Containers in the port of Kotka (Finland) on the Baltic Sea. ...
The large trailers pulled by a semi come in many styles, lengths, and shapes. Some common types are: vans, reefers, flatbeds, containerlifts 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 (thick unthreaded bolts). The purpose of this is to help adjust weight distribution over the various axles, to comply with local laws. A containerlift is a road going truck or semi-trailer used to hoist, stack and transport ISO standard containers. ...
Etymology Semi-trailer is the name of the kind of trailer that a prime mover pulls, but in general use refers to the whole assembly.
See also A dump truck is a truck used for transporting loose material (such as sand, gravel, or dirt) for construction. ...
Freightliner, LLC is a truck tractor manufacturer. ...
Kenworth is one of the primary manufacturers of heavy duty class 8 trucks. ...
Mack Trucks is a famous United States truck manufacturing company, now owned by Volvo. ...
Peterbilt Motors is one of the primary producers of heavy duty class 8 trucks. ...
Scania AB is a Swedish truck manufacturer. ...
A trucker is a person who is employed as a truck driver (particularly of semi-trailers). ...
External links |
Feeds |
Contact