A ballast tractor is a specially weighted

tractor unit A tractor unit, also known as a truck unit, lorry unit, power unit, prime mover, ten-wheeler, semi-tractor, semi-truck, semi-lorry, tractor cab, truck cab, lorry cab, big rig tractor, big rig truck or big rig lorry or simply a tractor, truck, ...

of a heavy hauler combination. It is designed to utilize a drawbar to pull or push heavy or exceptionally large trailer loads which are loaded in a hydraulic modular trailer. When feasible, lowboy-style semi-trailers are used to minimize the height of a load's center of mass. Typical drivetrains are 6×4 and 6×6, but 8×6 and 8×8 are also available. Typical ballast tractor loads include oil rig modules, bridge sections, buildings, ship sections, and industrial machinery such as generators and turbines. Only a handful of manufacturers produce dedicated ballast tractors. Extra-heavy-duty chassis versions of mass-production tractor units are fitted with drawbar hitches and a separate ballast box as an alternative. These units are classified as N3 Category of large goods vehicle. Ballast tractors can be traced back to the 1940s when heavy haulers from the UK started employing purpose-built Scammell Showtracs, a short wheelbase 4×2 ballast tractor. Increasingly, remote-controlled, self-propelled modular transporters (SPMT) are being employed in traditional ballast tractor/trailer roles.

Etymology

The ballast tractor's name derives from the nautical term “ sailing ballast” describing heavy material added to a vessel to improve stability. For a ballast tractor, ballast is added over the driving wheels to maximize traction. The additional weight increases the friction between the tyres and the road surface, allowing the tractor to overcome the

inertia Inertia is the natural tendency of objects in motion to stay in motion and objects at rest to stay at rest, unless a force causes the velocity to change. It is one of the fundamental principles in classical physics, and described by Isaac Newto ...

and friction of moving a heavy trailed load. Without it, there would be unproductive wheelspin.

Description

With a semi-trailer, ballast is added in the form of the weight of the attached trailer pressing down upon the tractor's

fifth wheel The fifth-wheel coupling provides the link between a semi-trailer and the towing truck, tractor unit, leading trailer or dolly (trailer), dolly. The coupling consists of a kingpin (automotive part), kingpin, a vertical steel pin protruding ...

. Since the load is separate from a ballast tractor, it provides no ballast: the drawbar only transmits a horizontal force. High inertia is encountered when starting to move a heavy load. To overcome this, ballast tractors tend to have high-powered, low geared engines that provide substantial

torque In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...

, especially at low speeds. Additionally, ballast tractors are often fitted with heavy-duty hub reduction

axle An axle or axletree is a central shaft for a rotation, rotating wheel and axle, 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 ...

s, a combination resulting in exceptionally low maximum speeds. A strong chassis is required to both support the extra ballast weight and pulling forces transmitted by the drawbar. A reinforced chassis also allows multiple tractors to be coupled together to maximize power and traction. Heavy-duty versions of commercial tractor units may be fitted with a ballast box and suitable draw gear, or a ballast tractor may be purpose-built. Ballast is placed above the driving axle, or spread out over multiple driving axles to maximize traction on each and evenly distribute its load. Conversion from a regular tractor to a ballast tractor may require some modifications like chassis alteration, extra axle, larger tires, ballast box, and a heavy-duty gearbox so that it can handle the extra weight. The heavy-duty tractors which are usually converted into ballast tractors have 6x4, 8x6 axle configuration, hub reduction, better suspension and a powerful engine ranging from 300 to 1000hp. A purpose built ballast tractor tends to be the heaviest class of on-road trucks. In some cases, its kerb weight can be greater than their axle configuration's legal Gross Vehicle Weight (GVW) permits, requiring special permission to use public roads. Some nations have categorized these tractors in a different category than conventional tractors because of higher GVW permits and HMT configuration. Typical ballast tractor configurations employ an independent drawbar trailer, hydraulic modular trailer, or

dolly trailer A dolly is an unpowered vehicle designed for tow hitch, connection to a tractor unit, truck or prime mover vehicle with strong traction power. United States Classification by axle configuration There are several types of dolly Bogie#Articu ...

. An advantage of using ballast tractors is the ability to push-steer a trailer around a corner. A girder trailer, for example, is double-articulated, so the front tractor can pull the load around a corner while the rear tractor pushes it through, thereby making the load more manoeuvrable than a simple towing configuration. Use of a following tractor also can increase control and brake force descending an incline.

Equipment

Ballast box

The ballast box is a metal box installed on the rear chassis of the tractor instead of the fifth wheel coupling. Earlier heavy haulers unmounted the fifth wheel and used merely a piece or two of heavy rocks,

stones In geology, rock (or stone) is any naturally occurring solid mass or aggregate of minerals or mineraloid matter. It is categorized by the minerals included, its Chemical compound, chemical composition, and the way in which it is formed. Rocks ...

or concrete blocks which weighted enough to avoid wheel spin, later builders and heavy haulers developed metal boxes of different designs to match the tractor layout. These boxes were filled with

concrete Concrete is a composite material composed of aggregate bound together with a fluid cement that cures to a solid over time. It is the second-most-used substance (after water), the most–widely used building material, and the most-manufactur ...

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

to increase the weight of the tractor. The problem with ballast tractors was the weight of ballast itself weighted over 10, 20 or even 40 tons in some scenarios. Other designs also included sleeping cabins in the ballast for the drivers and the

crew A crew is a body or a group of people who work at a common activity, generally in a structured or hierarchy, hierarchical organization. A location in which a crew works is called a crewyard or a workyard. The word has nautical resonances: the ta ...

for longer journeys and harsh weather conditions, This made the height of the tractors increase significantly, these units are still used today in the gulf area due to extreme heat. Some units have factory fitted ballast box with appropriate weight to meet with the regional guidelines, these tractors units do not have fifth wheel and drive out from the factory with a ballast box. Heavy haul operators convert heavy-duty tractors to ballast tractors with an aftermarket ballast box built by a builder or by themselves. New age power boosters which are external engine an accessory of hydraulic modular trailer can also be mounted on the tractor chassis to act as a ballast, saving a lot of space on the trailer itself for the loads and most important avoid application of extra tractors. Mammoet and Scheuerle (Member of the TII Group) have proved this configuration in 2019 on a difficult terrain in

Norway Norway, officially the Kingdom of Norway, is a Nordic countries, Nordic country located on the Scandinavian Peninsula in Northern Europe. The remote Arctic island of Jan Mayen and the archipelago of Svalbard also form part of the Kingdom of ...

. Almost all HMT manufacturers have their own variant of power booster.

Drawbar coupling

Drawbar coupling is a special tow hitch mounted on the front end or rear end of the tractor, sometimes both, it connects the HMT to the ballast tractor. Earlier coupling consisted of in house made metal hitch which had loops to lock drawbar eyes with a pin. Later fifth wheel manufacturers like Jost Rockinger and Ringfeder developed heavy-duty drawbar couplings with a 50 mm loop, drawbars and drawbar eyes which were built with higher quality and standards this increase the safety significantly. These couplings can be mounted on both ends of the tractor for push or pull applications. Some manufacturers also provide tractors with drawbar coupling fitted from the factory.

Manufacturers

Only a handful of manufacturers produce dedicated ballast tractors. Most high-volume manufacturers offer heavy-duty chassis versions of certain tractor units, which enable a ballast box to be fitted. In Europe, manufacturers tend to send some of their products to another company (owned by the parent) to be converted into a special heavy-duty version. ;Belarus * Volat ;Belgium * MOL ;Canada * Hayes *

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

;Czech Republic * Tatra ;France * Nicolas Tractomas 8×8 and 10×10 ultra-heavy-duty tractors * PRP * Willème ;Germany * Tadano Faun GmbH *

MAN A man is an adult male human. Before adulthood, a male child or adolescent is referred to as a boy. Like most other male mammals, a man's genome usually inherits an X chromosome from the mother and a Y chromosome from the f ...

/ ÖAF *

Mercedes-Benz Mercedes-Benz (), commonly referred to simply as Mercedes and occasionally as Benz, is a German automotive brand that was founded in 1926. Mercedes-Benz AG (a subsidiary of the Mercedes-Benz Group, established in 2019) is based in Stuttgart, ...

(Titan) ;India * Volvo Trucks India * Scania India ;Italy * Astra-SIVI (Iveco) ;Netherlands * DAF (GINAF) ;Russia (formerly Soviet Union) * MAZ * NAMI ;Spain * TBO Trabosa * TMU ;Switzerland * NAW ;UK * AEC * Atkinson Vehicles * ERF * Foden Trucks * Rotinoff Motors – 35 heavy haulage tractors were built by the company between 1952 and 1959, of which 11 are known to survive. * Scammell – Many early examples, now used and seen as showman's vehicles, originally served with the army. * Thornycroft -such as Thornycroft Antar * Unipower ;USA * Diamond T - Ex-army Diamond T M20 tank transports were popular post World War II with heavy hauliers in the UK. *

Kenworth Kenworth Truck Company is an List of American truck manufacturers, American truck manufacturer. Founded in 1923 as the successor to Gersix Motor Company, Kenworth specializes in production of heavy-duty (Truck classification#Class 8, Class 8) ...

* Mack *

White White is the lightest color and is achromatic (having no chroma). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully (or almost fully) reflect and scatter all the visible wa ...

Oshkosh Corporation Oshkosh Corporation, formerly Oshkosh Truck, is an American industrial company that designs and builds specialty trucks, military vehicles, truck bodies, airport fire apparatus, and access equipment. The corporation also owns Pierce Manufact ...

Operators

Most heavy haulage and heavy lift engineering firms employ heavy duty tractor-unit models that can accommodate a ballast box. Countries where modernization is taking place, such as regions of the Middle East and South Africa and Asia, operate larger number of ballast tractors due to the greater frequency of heavy loads (such as power station components) and infrastructure projects. Apart from being used by fairgrounds as a direct replacement for the steam-powered showman's engine, specialist moving and haulage companies use ballast tractors. These include: *

Alstom Alstom SA () is a French multinational rolling stock manufacturer which operates worldwide in rail transport markets. It is active in the fields of passenger transportation, signaling, and locomotives, producing high-speed, suburban, regional ...

* Mammoet * Pickfords * Sarens * ALE * Lampson International * CLP Group * Omega Morgan * Defence Research and Development Organisation

Gallery

File:0133 2019-03 Goldhofer FTV 300.jpg, Mercedes-Benz SK Ballast Tractor pulling Goldhofer hydraulic modular trailer with FTV 300 blade lifter carrying a Windmill blade. File:0145 2019-03 Goldhofer »FAKTOR« 5.jpg, Ballast Tractor Pushing Goldhofer hydraulic modular trailer with Faktor 5 girder bridge. File:Pickfords.jpg, Scammell Contractor ballast tractor pulling specialist trailer at a fair File:Atkinson Ballast Tractor - fairground livery lookalike.jpg, Atkinson ballast tractor File:Scammell Ballast Tractor - fairground livery.jpg, Scammell ballast tractor. Note the front drawbar coupling for pushing heavy loads File:RotinofF5-2947.jpg, Three of the 11 surviving Rotinoff Atlantic ballast tractors File:Scheuerle Fahrzeugfabrik Schwerlastmodul InterCombi.jpg, An

and a

Volvo The Volvo Group (; legally Aktiebolaget Volvo, shortened to AB Volvo, stylized as VOLVO) is a Swedish multinational manufacturing corporation headquartered in Gothenburg. While its core activity is the production, distribution and sale of truck ...

ballast tractor pulling load on TII hydraulic modular trailer. File:Rotran Set Nicolas Tractomas.jpg, TII Nicolas Tractomas ballast tractor. File:Abnormal Vehicle. Rotran Set headed by a Nicolas Tractomas Truck, 2 International Pacifics (Ex SAR) with a Girder Beam on two Multi Axle Nicolas Trailers (21442866448).jpg, TII Nicolas Tractomas ballast tractors pulling a hydraulic modular trailer with girder bridge. File:Oversize transport towards BASF.jpg,

ballast tractor pushing hydraulic modular trailer with bolster configuration. File:Abnormal Load 360 Tons. Ale Near Hendrina. (12035617625).jpg, ALE Faun custom ballast tractor. File:ALE Abnormal load in Kincardine (4514127619).jpg, ALE Trojan ballast tractor pushing hydraulic modular trailer with girder bridge configuration. File:MAN 41-603 tractor unit, Abnormal Load Engineering, London E5. 22 March 2009.jpg, ALE

ballast tractor with drawbar connected to a hydraulic modular trailer. File:Overweight load transport.JPEG,

ballast tractor pulling hydraulic modular trailer.

References

External links

Extremely large collection of heavy haulage photos
{{DEFAULTSORT:Ballast Tractor Trucks Heavy haulage