digplanet beta 1: Athena
Share digplanet:

Agriculture

Applied sciences

Arts

Belief

Business

Chronology

Culture

Education

Environment

Geography

Health

History

Humanities

Language

Law

Life

Mathematics

Nature

People

Politics

Science

Society

Technology

For more details on "prime mover", see ballast tractor.
Oshkosh M1070 8×8 military tractor unit
Peterbilt 386 cab style commercial 6×4 tractor unit

A tractor unit (prime mover or traction unit) is a characteristically heavy-duty towing engine that provides motive power for hauling a towed or trailered load. These fall into two categories: very heavy-duty typically off-road capable, often 6×6, military and commercial tractor units, including ballast tractors, and heavy and medium duty military and commercial rear-wheel drive "semi tractors" used for hauling semi-trailers.

Tractor units typically have large displacement diesel engines for power, durability, and economy, and several axles for maximum flexibility in gearing.

The tractor-trailer combination distributes a load across multiple axles while being more maneuverable than an equivalently sized rigid truck. The most common trailer attachment system is a fifth wheel coupling, allowing rapid shift between trailers performing different functions, such as a bulk tipper and box trailer. Trailers containing differing cargos can be rapidly swapped between tractors, eliminating downtime while a trailer is unloaded or loaded.

Drawbar couplings are also found, particularly in dedicated exceptionally heavy-duty ballast tractors.

Configurations[edit]

Cab[edit]

A Leyland T45 cab-over 4×2 tractor unit

There have been three common cab configurations used in tractors, two are still widely used. The conventional has an engine and hood over the front axle in front of the cab, as in most automobiles. This style is almost universal in the North America. The cab over engine has a flat nose cab with the driver sitting in front of the front axle. Widely used in the EU, this style has the advantages of good vision, maneuverability, and allows maximum trailer length relative to overall length. In the North America this type of cab can be useful in strait trucks, but now has little advantage in tractors and is rarely used. A North American style cab over engine, now largely obsolete, had a flat nose cab located higher over the engine, with the driver sitting above the front axle. This allowed a sleeper compartment in a short tractor, and maximum wheelbase relative overall length, important for bridge formula weight restrictions. With the loosening of length restrictions in 1982 this style had limited applications, and is no longer manufactured in the U.S.[1][2][3][4][5][6]

Axle[edit]

An 8×8 Oshkosh M1070 Heavy Equipment Transporter tractor unit pulling a lowboy style trailer

A tractor unit can have many axles depending on axle load legislation. The most common varieties are those of 4×2, 6×2 and 6×4 types[a]. However, some manufacturers offer 6×6, 8×6, 8×8, 10×8, and 10×10 axle configurations. A 6×4 has three axles, with two of the axles driven. 6×4 units are more common in long distance haulage in larger countries such as the USA and Australia. In Europe, the 4×2 and 6×2 variants are more commonplace.

Tractors with three axles or more can have more than one steering axle, which can also be driven. Most 6×2 units allow the undriven rear axle to be raised when lightly loaded, or running without a trailer, to save tyre wear, and increase traction. The 6×6 units have three axles, all driven, and 8×6 units have four axles, with either the rear three driven and the front axle not or the front and rear-most two axles powered and an unpowered lifting bogey axle to spread the load when needed. The 8×8 units also have four axles, but with all of them driven, and 10×8 units have five axles with the rear four usually driven and the front axle for steering. All five axles of 10×10 units are driven. The front two axles are usually both steer axles. The axle configurations are usually based on axle load legislation, and maximum gross vehicle weight ratings (BDM).

Heavier versions of tractor units, such as those used in heavy haulage and road trains, tend to have four or more axles, with more than two axles driven. In certain countries (such as Switzerland), a certain amount of weight must be spread over driven axles, which lead to heavier varieties having six-wheel drive, otherwise another tractor unit would have to be used. Heavy haulage variants of tractor-units are often turned into a ballast tractor by fitting temporary ballast, which may require special permitting.[1][2][7]

See also[edit]

References[edit]

  1. ^ a b "Freight Management and Operations: Bridge Formula Weights". U.S. Department of Transportation. Retrieved 25 June 2013. 
  2. ^ a b "Freight Management and Operations: Size Regulations". U.S. Department of Transportation. Retrieved 25 Jun 2013. 
  3. ^ "International Trucks (U.S.)". Navistar, Inc. 2013. Retrieved 25 June 2013. 
  4. ^ "Mack Trucks (U.S.)". Mack Trucks, Inc. 2013. Retrieved 25 June 2013. 
  5. ^ "Mercedes-Benz Truck (Germany)". Daimler AG. 2013. Retrieved 25 June 2013. 
  6. ^ "Volvo Trucks (Worldwide)". AB Volvo. Retrieved 25 June 2013. 
  7. ^ "Guidelines on Maximum Weights…Criteria (EU)" (PDF). Road Safety Authority. 2013. Retrieved 25 June 2013. 

Notes[edit]

  1. ^ Total wheels X driven wheels, with 2 wheels per axle regardless of single or dual tires.

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Tractor_unit — Please support Wikipedia.
This page uses Creative Commons Licensed content from Wikipedia. A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia.
260984 videos foundNext > 

SCANIA R480 6X4 DOUBLE DRIVE TRACTOR UNIT

EVE Online - Pinpointing 250mil ISK 'Magpie' Mobile Tractor Unit

Another 'Magpie' Mobile Tractor Unit put out of its misery. Farewell Mr. Magpie. I'm sure you served your master well. May you rest in peace. 'Magpie' Mobile ...

EVE Online • Mobile Tractor Unit Cleanup

Subscribe for more videos ▻ http://goo.gl/5UD6wY Follow Me on Google+ ▻ http://goo.gl/HYKs2e Follow Me on Twitter ▻ http://goo.gl/Ze8K35 Ken wants to go ...

Mobile Tractor Units - Rubicon

Subscribe for more videos ▻ http://goo.gl/5UD6wY Follow Me on Google+ ▻ http://goo.gl/HYKs2e Follow Me on Twitter ▻ http://goo.gl/Ze8K35 Ken wants to go ...

Копаем руду с Mobile Tractor Unit и пару слов о Mobile Depot.

EVE Online Тестим новый модуль который появился с патчем Рубикон. Копаем, выкидываем в космос, а Mobile Tractor Unit подт...

Mobile Tractor Unit in Level 4 missions - EVE Online

Trying out the new Mobile Tractor Unit in a Level 4 mission. It's quite a handy tool that makes salvaging and collecting wreck loot a breeze. EVE Online Rubicon.

EVE Online: Salvaging with the Mobile Tractor Unit - How real men salvage.

Try EVE Online for free with this extended trial: https://secure.eveonline.com/trial/?invc=ba576d5d-9cf2-4041-8263-57435387fa52&action=buddy With the ...

Эксплоит Mobile Tractor Unit

EVE Online Видео о том как слить карибаса используя странную механику игры. Обсудить можно здесь: https://forums.eveonline.c...

Merceds Benz New Actros Gigaspace Tractor Unit 6x6 Building Report

Mercedes Benz Actros Gigaspace Sattelzugmaschine 6x6 Building Set is from........ www.ScaleArt.de Don´t forget to Like my Video! Thumps up! And please ...

Mercedes Benz Actros II Tractor Unit 6x6 building report Part 10

The Actros Modell is from ScaleArt Saddle plate from AFV Modell And please dont forget to Like my Videos! Helmut.

260984 videos foundNext > 

1071 news items

hngnews.com

hngnews.com
Tue, 30 Jun 2015 13:31:05 -0700

Ethan Schmidt of DeForest, drove a miniature John Deere Gator through the Marshall Firemen's Festival parade on Sunday as part of the Dodge's Poppers John Deere Tractor unit. it was sprinkling at the time of the parade and Schmidt was dressed for the ...

Waynesville Daily Guide

Waynesville Daily Guide
Wed, 24 Jun 2015 10:15:00 -0700

Firefighters were dispatched at around 11:37 a.m. to the “fully-involved” semi fire, which Williams said may have been caused by an issue with the vehicle's brakes. Williams said the driver was able to disconnect the tractor unit from the trailer and ...

CFO

CFO
Fri, 19 Jun 2015 11:35:02 -0700

There would be different standards for the load-pulling tractor unit of large so-called semitrailers and for the trailer it hauls. The tractor standard will require that a truck built in 2021 and beyond be up to 24% more fuel efficient and emit up to ...

Transport Evolved

Transport Evolved
Wed, 24 Jun 2015 03:09:06 -0700

... digital video cameras, wireless communication and large-screen video monitors — the trucks capture the image of the road ahead via a small wide-angle camera mounted into the front bumper of the tractor unit, then beam it to the rear of the truck ...

Miami County Republic

Miami County Republic
Wed, 24 Jun 2015 06:12:25 -0700

A large tractor unit pulled the trailer from the front, and another tractor unit pushed from behind. Before the slug catcher could be placed on top, a test lift had to be performed using a 300-ton crawler crane provided by Belger Cartage and slings ...
 
OE Digital
Fri, 05 Jun 2015 13:03:45 -0700

Technip's new tool can interrogate an installation process, and advice on the best setup, including pad size, type and spacing on an installation tractor unit. Alternatives to the tool considered and rejected by Technip include physical testing, which ...

Forbes

Forbes
Wed, 24 Jun 2015 15:01:07 -0700

He sold all but two, including the legacy tractor unit, to focus on motorcycles and trucks. In 2009 Eicher's fortunes turned when it launched the Classic, a bike with vintage features but a modernized engine. It was an instant bestseller and remains ...

CBC.ca

CBC.ca
Fri, 26 Jun 2015 10:56:21 -0700

A 55-year-old Mount Stewart man was pronounced dead on the scene after a head-on collision in the community of Bristol, just west of Morell, around noon Friday, say RCMP. Kings District RCMP, the Morell Fire Department, Island EMS and a collision ...
Loading

Oops, we seem to be having trouble contacting Twitter

Support Wikipedia

A portion of the proceeds from advertising on Digplanet goes to supporting Wikipedia. Please add your support for Wikipedia!

Searchlight Group

Digplanet also receives support from Searchlight Group. Visit Searchlight