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.[1]
Etymology
Piggyback is a corruption of pickaback, which is likely to be a folk etymology alteration of pick pack (1560s), which perhaps is from pick, a dialectal variant of the verb pitch.[2]
Examples
Human locomotion
A handball game with piggybacking players in Ancient Greece circa. 500 BCE
Piggybacking may also feature in the context of play or sport, and evidence of this dates back to Ancient Greece where games involving piggyback riding were combined with the requirement of catching or throwing a ball.[3] 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.
Trucks on a train in IndiaA train of coupled Commonwealth Railways narrow-gauge cattle cars on continuous rails laid on standard gaugeflatcars (outback Australia)
In rail transport, the practice of carrying trailers or semi-trailers in a train atop a flatcar is referred to as "piggybacking".[4] Early drawings of the Liverpool & Manchester Railway c1830 show road coaches being piggybacked on railway flat wagons.[5]
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.[6][7]
A railway wagon of one track gauge can be carried on a flat wagon (transporter wagon or rollbock) of another gauge. In addition, an entire train of coupled wagons of one gauge can be carried on continuous rails on a train of flat wagons of another gauge. This was achieved by the Commonwealth Railways on the Marree railway line in South Australia between Telford Cut and Port Augusta in the mid-1950s.[8][9] Japan Railways planned a similar "Train on Train" scheme, but at much higher speeds, to operate from 2016.[10]
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 was carried on top of specially-modified Boeing 747Shuttle Carrier Aircraft when the shuttle landed at places other than Kennedy Space Center.
Space
In space transportation systems, a smaller satellite 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 and having to remain on a similar orbit to that of the big satellite.
Military
The metal caterpillar treads of a tank 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.
^Piggback: The Trailer Train story Railway Age May 25, 1964 page 44
^Field, Alexander J (2011). A great leap forward: 1930s depression and U.S. economic growth. New Haven, London: Yale University Press. p. 114. ISBN978-0-300-15109-1.
^独自の研究開発 人と物流 高速化に活路 [Own R&D leading to increased speed]. Hokkaido Shimbun (in Japanese). Japan: The Hokkaido Shimbun Press. 20 December 2008. Retrieved 30 September 2009.
.jpg)
_(6265367138).jpg)
