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Horseshoe curve
Roadbed that turns 180 degrees / From Wikipedia, the free encyclopedia
For other uses, see Horseshoe Curve (disambiguation).
See also: Hairpin turn
A horseshoe curve is a class of climbing curve in a roadbed that reverses turn direction (inflection) twice on either side of a single tight curve that varies through an angle of about 180 degrees or more.
Aerial shot of the Horseshoe Curve that helps trains cross the Allegheny Mountains west of Altoona, Pennsylvania.
Such curves are more commonly found in a railway line but are also used in roads. The characteristic U shape, or even slight balloon shape, of such a curve resembles a horseshoe. On roadways, particularly tight versions of such curves are typically called hairpin turns.