A semi-trailer truck, also known as a semi-truck, (or semi, big rig, tractor-trailer, or eighteen-wheeler) is the combination of a tractor unit and one or more semi-trailers to carry freight. A semi-trailer attaches to the tractor with a type of hitch called a fifth wheel.
The Studebaker US6 (G630) was a series of 2+1⁄2-ton 6×6 and 5-ton 6×4 trucks manufactured by the Studebaker Corporation and REO Motor Car Company during World War II. The basic cargo version was designed to transport a 2+1⁄2-short-ton cargo load over any type of terrain in any weather. Most of these were exported to the Soviet Union under Lend-Lease by the USA during World War II, since the competing GMC 6×6 CCKW design proved to be more suitable for Western Front conditions.
The M939 is a 5-ton 6×6 U.S. military heavy truck. The basic cargo versions were designed to transport a 10,000 pounds (4,500 kg) cargo load over all terrain in all weather. Designed in the late 1970s to replace the M39 and M809 series of trucks, it has been in service ever since. The M939 evolved into its own family of cargo trucks, dump trucks, semi-tractors, vans, wreckers, and bare chassis/cabs for specialty bodies. 44,590 in all were produced.
The M19 Tank Transporter was a heavy tank transporter system used in World War II and into the 1950s. It consisted of a 12-ton 6x4 M20 Diamond T Model 980 truck and companion 12-wheel M9 trailer.
The M39 series 5-ton 6×6 truck (G744) was a family of heavy tactical trucks built for the United States Armed Forces. The basic cargo version was designed to transport a 5-ton (4,500 kg), 14 ft (4.3 m) long load over all terrain in all weather. In on-road service the load weight was doubled.
The M25 Tank Transporter (G160) was a combination 6x6 M26 armored heavy tank transporter/tank recovery tractor and companion 40-ton M15 trailer introduced into US Army service in Europe in 1944–45. Manufactured by Pacific Car & Foundry Co., it was a substantial upgrade over the Diamond T M19 transporter/trailer duo introduced in 1940.
The G-506 trucks, 1+1⁄2-ton, 4x4, produced as the Chevrolet G7100 models, were a series of (light) medium four wheel drive trucks used by the United States Army and its allies during and after World War II. This series came in standard cargo, as well as many specialist type bodies.
The Willys MC, formally the 1⁄4-Ton, 4 x 4, Utility Truck M38, or the G‑740 by its U.S. Army Standard Nomenclature supply catalog designation, is a quarter-ton four-wheel drive military light utility vehicle made by Willys between 1949 and 1952. It replaced, and succeeded the World War II Willys MB and Ford GPW models, with a total production of some 50,000 units — less than one tenth the number of WWII models built. Unlike during WWII, Ford was no longer involved in the production.
The M915 is a tractor unit used for line haul missions by the United States Army. Designed for use on improved roads it does not have a driven front axle.
The Mack model EH trucks were a family of 4x2 trucks used by the US and British military before and during World War II. They were built in conventional and cab-over-engine models and were used as both trucks and semi-tractors. Originally a commercial design, in 1943 a military version became standard.
The Mack M123 (G792) was a 10-ton 6x6 semi-tractor introduced in 1955; the Mack M125 was a heavy cargo truck version of the M123. The M123 was used to tow tank transporter trailers while the M125 towed field artillery pieces.
The Mack NJU 5- to 6-ton 4x4 Ponton tractor (G639) was a semi-tractor designed to haul bridging equipment during World War II. Of the 700 built 119 were supplied to the British in Egypt, 8 were built with van bodies, and the rest were used as a substitute standard by the US Army.
The Autocar Model U8144T, officially "5- to 6-Ton, 4×4, Ponton Tractor Truck", was the largest, and most heavy-duty, of a family of heavy four-wheel drive trucks developed for, and deployed primarily with, the United States Army in World War II. They were of a "cab over engine" design, and produced by the Autocar Company from 1941 to 1945 with 2,711 being built.
Mack Trucks has been selling heavy duty trucks and buses to the United States military since 1911. Virtually every model has been used. The majority have been commercial models designed and built by Mack with their own components, but they have also designed and built military specification tactical trucks. The military vehicles are rated by payload measured in tons.
The M809 Series 5-ton 6x6 truck (G908) was a family of heavy tactical trucks built for the United States Armed Forces. The basic cargo version was designed to transport a 5-ton (4,500 kg), 14 ft (4.3 m) long load over all terrain in all weather. In on-road service the load weight was doubled. Built by AM General, they evolved into the M939 Series.
The 6-ton 6×6 truck was a family of heavy tactical trucks built for the United States Army during World War II. The basic cargo version was designed to transport a 6- short ton (5,400 kg) cargo load over all terrain in all weather. The chassis were built by Brockway Motor Company, The Corbitt Company, The Four Wheel Drive Auto Company (FWD), Ward LaFrance Truck Corporation, and White Motor Company. They were replaced by the M54 5-ton 6x6 trucks in the 1950s.
The 5‑ton 6x6 truck, officially "Truck, 5-ton, 6x6", was a class of heavy-duty six-wheel drive trucks used by the US Armed Forces. The basic cargo version was designed to transport a 5-ton (4,500 kg) load over all roads and cross-country terrain in all weather. Through three evolutionary series there have been component improvements, but all trucks were mechanically very similar. They were the standard heavy-duty truck of the US military for 40 years, until replaced by the Medium Tactical Vehicle (MTV) beginning in 1991.
The Kenworth 10-ton 6x6 heavy wrecking truck (G116) was the standard heavy wrecker of the US Army during World War II. It was replaced in the 1950s by 5-ton wreckers.
The Diamond T 4-ton 6×6 truck was a heavy tactical truck built for the United States Army during World War II. Its G-number was G-509. Cargo models were designed to transport a 4-ton (3,600 kg) load over all terrain in all weather. There were also wrecker, dump, and other models. They were replaced by the M39 series 5-ton 6×6 trucks in the 1950s.
