Piggyback transportation refers to the transportation of goods where one transportation unit is carried on the back of something else. It is a specialised form of intermodal transportation and combined transport.

Etymology

''Piggyback'' is a corruption of ''pickaback'', which is likely to be a folk

etymology Etymology ( ) is the study of the origin and evolution of words—including their constituent units of sound and meaning—across time. In the 21st century a subfield within linguistics, etymology has become a more rigorously scientific study. ...

alteration of ''pick pack'' (1560s), which perhaps is from ''pick'', a dialectal variant of the verb ''pitch''.

Examples

Human locomotion

A person carrying someone else on their back is most commonly seen in the modern day in the form of a

parent A parent is either the progenitor of a child or, in humans, it can refer to a caregiver or legal guardian, generally called an adoptive parent or step-parent. Parents who are progenitors are First-degree relative, first-degree relatives and have ...

carrying an underage

child A child () is a human being between the stages of childbirth, birth and puberty, or between the Development of the human body, developmental period of infancy and puberty. The term may also refer to an unborn human being. In English-speaking ...

, either for travelling or for children's games. It can involve the carrier crawling on hands and knees with the child straddling over the back like riding a horse, or with the carrier standing upright with the child hugging or cradled behind the back, often with the child's arms leaning over the carrier's shoulders and legs wrapping around the flanks. Piggybacking may also feature in the context of play or sport, and evidence of this dates back to

Ancient Greece Ancient Greece () was a northeastern Mediterranean civilization, existing from the Greek Dark Ages of the 12th–9th centuries BC to the end of classical antiquity (), that comprised a loose collection of culturally and linguistically r ...

where games involving piggyback riding were combined with the requirement of catching or throwing a ball. In the modern era, wife carrying competitions, where the female participants ride on the back of their male partners running the race, are popular in some countries.

Rail

In rail transport, the practice of carrying trailers or semi-trailers in a train atop a flatcar is referred to as "piggybacking". Early drawings of the Liverpool & Manchester Railway c1830 show road coaches being piggybacked on railway flat wagons. The rail service provided for trucks which are carried on trains for part of their journey is referred to as a rolling road, or rolling highway. A related transportation method is the rail transport of semi-trailers, without road tractors, sometimes referred to as "trailer on flatcar (TOFC)". In the United States, TOFC traffic grew from 1% of freight in 1957 to 5% in 1964 and 15% in 1986. A rail vehicle of one

track gauge In rail transport, track gauge is the distance between the two rails of a railway track. All vehicles on a rail network must have Wheelset (rail transport), wheelsets that are compatible with the track gauge. Since many different track gauges ...

can be carried on a flatcar ( transporter wagon or rollbock) of another gauge. In addition, an entire train of coupled cars of one gauge can be carried on continuous rails on a train of flatcars of another gauge. This was achieved, as a temporary expedient, by the Commonwealth Railways on the Marree railway line in South Australia between Telford Cut and

Port Augusta Port Augusta (''Goordnada'' in the revived indigenous Barngarla language) is a coastal city in South Australia about by road from the state capital, Adelaide. Most of the city is on the eastern shores of Spencer Gulf, immediately south of the ...

in the mid-1950s. Japan Railways planned a similar " Train on Train" scheme, but at much higher speeds, to operate from 2016.

Trucking

For semi trucks the trucks can be stacked 4 deep if it is just a day-cab truck and only 3 deep if it has a sleeper-cab. The trucks drive up a ramp or are lifted into place by a tow hook on the front bumper, from a heavy-duty tow truck or overhead crane. A saddle is placed on the fifth-wheel, that the front axel of the next truck is attached to, which is called decking. The mirrors are folded in on the trucks being hauled for width requirements and safety. For undecking the trucks, a tow truck or overhead crane is used again. It is typically used to transport newly built or purchased trucks.

Marine

Small ships of all kinds can be piggybacked on larger ships. Examples include lifeboats, landing craft, and minesweepers on motherships, as well as midget submarines on larger

submarine A submarine (often shortened to sub) is a watercraft capable of independent operation underwater. (It differs from a submersible, which has more limited underwater capability.) The term "submarine" is also sometimes used historically or infor ...

s, such as those used for the 1942 Japanese submarine attack on Sydney.

Air transport

The 1930s British Short Mayo Composite, in which a smaller, four-engine floatplane aircraft named Mercury was carried aloft on the back of a larger four-engine flying boat named Maia, enabled the Mercury to achieve a greater range than would have been possible had it taken off under its own power. The American

Space Shuttle The Space Shuttle is a retired, partially reusable launch system, reusable low Earth orbital spacecraft system operated from 1981 to 2011 by the U.S. National Aeronautics and Space Administration (NASA) as part of the Space Shuttle program. ...

was carried on top of specially-modified

Boeing 747 The Boeing 747 is a long-range wide-body aircraft, wide-body airliner designed and manufactured by Boeing Commercial Airplanes in the United States between 1968 and 2023. After the introduction of the Boeing 707, 707 in October 1958, Pan Am ...

Shuttle Carrier Aircraft when the shuttle landed at places other than Kennedy Space Center.

Space

In space transportation systems, a smaller

satellite A satellite or an artificial satellite is an object, typically a spacecraft, placed into orbit around a celestial body. They have a variety of uses, including communication relay, weather forecasting, navigation ( GPS), broadcasting, scient ...

that is carried as a secondary payload on a launch is said to be "piggybacked" on the main launch. It is often the case of small satellites and cubesats, since they can not usually afford accessing space on a dedicated launch and they choose instead to take profit of the remaining payload capacity in a big satellite launch. However, this is usually at the cost of not being able to fly to their desired

orbit In celestial mechanics, an orbit (also known as orbital revolution) is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an ...

and having to remain on a similar orbit to that of the big satellite.

Military

The metal caterpillar treads of a

tank A tank is an armoured fighting vehicle intended as a primary offensive weapon in front-line ground combat. Tank designs are a balance of heavy firepower, strong armour, and battlefield mobility provided by tracks and a powerful engine; ...

wear out quickly when travelling long distances on ordinary roads. Also, tracked vehicles seriously damage the tarmac layer of ordinary roads (unless the caterpillar treads are specially fitted with rubber pads to avoid this). It is therefore necessary to provide tank transporters, which have rubber tires, to the battlefield.

Gallery

File:MBC Ua 235A.JPG, Timber wagon on rollbocks File:20090803 hellenic spirit25.jpg, Trucks on board a ro-ro ship File:South Australian Railways narrow gauge locomotive T232 on broad gauge crocodile car.jpg, A

South Australian Railways South Australian Railways (SAR) was the organisation through which the Government of South Australia built and operated railways in South Australia from 1854 until March 1978, when its non-urban railways were incorporated into Australian Natio ...

T class narrow-gauge locomotive on a broad-gauge crocodile car File:Atlantis on Shuttle Carrier Aircraft.jpg, The Space Shuttle ''Atlantis'' atop a

NASA The National Aeronautics and Space Administration (NASA ) is an independent agencies of the United States government, independent agency of the federal government of the United States, US federal government responsible for the United States ...

File:Trajekt im Strom.jpg, Bonn–Oberkassel train ferry File:ROLA Kelenfold.JPG, Rolling road File:The Queen Mary's Army Auxiliary Corps during the First World War, France Q11512.jpg, A person being carried piggy-back at the beach (1918) File:The End (for now) (6265367138).jpg, Trailers on flatcars in the United States

References

External links

Double Piggyback p120

{{DEFAULTSORT:Piggy-Back (Transportation) Transport operations Intermodal transport