Piggy-back

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Rolling road redirects here, for other uses see Rolling road (disambiguation)

In transportation Piggy-back refers to transportation of goods where one transportation unit is carried on the back of something else - it is a specialised form of intermodal transportation and of combined transport. The term originated from the human practice known as 'piggybacking' where one person rides around on another's back.

Examples

Rail

trucks on a train

In rail transport, the practice of carrying trailers, or semi-trailers in a train atop a flatcar is referred to as "piggybacking."^[1]

When loaded trucks are carried on railway wagons, with facilities to complete the journey by road by rail-road transfer the train service is referred to as a rolling road, a related term is Trailer on Flatcar, (TOFC)

It is also possible to carry a railway wagon of one track gauge on a flat railway wagon (transporter wagon or rollbock) of another gauge; indeed, whole trains of one gauge can be carried on a train of flat wagons of another gauge as was done temporarily in Australia for a few years from 1955 between Telford and Port Augusta.^[2] It was also temporarely done on the Central Australia Railway while the standard gauge replacement was being built.

Marine

Small ships of all kinds can be piggybacked on larger ships. Examples include lifeboats, landing craft, minesweepers on motherships ^[3]. Midget submarines on big submarines such as used for 1942 Japanese submarine attack on Sydney.

Air transport

The 1930s British Short Mayo Composite, in which a smaller floatplane aircraft, the four-engined "Mercury", was carried aloft on the back of a larger four-engined flying boat named "Maia"; this enabled the Mercury to achieve a greater range than would have been possible had it taken off under its own power. In space transportation systems a satellite on the top of a launcher assembly is said to be "piggybacked" on the launcher.

Military

The metal caterpiller treads of a tank wear out quickly when travelling long distances on ordinary roads. It is therefore necessary to provide tank transporters which have rubber tires to the battlefield.

Gallery

Transporter wagon   Timber wagon on rollbocks   S.20 Mercury atop Maia.   The Space Shuttle atop a NASA Boeing 747.   Bonn–Oberkassel train ferry   Rolling road

See also

• Autorack
• Fireman's carry
• Bière–Apples–Morges Railway

References

External links

Wikimedia Commons has media related to: Piggy-back transport

• Double Piggyback p120
• RGI Modalohr