Tandem
Tandem, or in tandem, is an arrangement in which a team of machines, animals or people are lined up one behind another, all facing in the same direction.[1]
For other uses, see Tandem (disambiguation).
The original use of the term in English was in tandem harness, which is used for two or more draft horses, or other draft animals, harnessed in a single line one behind another, as opposed to a pair, harnessed side by side, or a team of several pairs. The tandem harness allows additional animals to provide pulling power for a vehicle designed for a single animal.
The English word tandem derives from the Latin adverb tandem, meaning at length or finally.[2] It is a word play, using the Latin phrase (referring to time, not position) for English "at length, lengthwise".[3]
Tandem bicycles are named for their tandem seating, a more common arrangement than side-by-side "sociable" seating. Tandem can also be used more generally to refer to any group of persons or objects working together, not necessarily in line.[1]
Trucks[edit]
In heavy trucks tandem refers to two closely spaced axles. Legally defined by the distance between the axles (up to 2.5 m (8 ft 2+3⁄8 in) in the European Union, 40–96 inches (1.02–2.44 m) in the United States), mechanically there are many configurations. Either or both axles may be powered, and often interact with each other. In the United States, both axles are typically powered and equalized; in the European Union, one axle is typically unpowered, and can often be adjusted to load, and even raised off the ground, turning a tandem into a single-axle.[4][5]
During mating among odonata (dragonflies and damselflies), a male uses claspers at the end of his abdomen to grab a female between the head and thorax, forming a tandem. The pair may take flight while in tandem. [8]: 5–6 [9]: 5