Etymology The noun is derived from switch (“to turn (a train) from one railway track to another using a switch”, verb) + back (“so as to reverse direction and return”, adverb). The verb is derived from the noun.
1
Rail transport, Railways, TransportFiguratively, Often A railway track on a steep slope in a zigzag formation, in which a train travels in a reverse direction at each switch.
"Of course," said Harry, "there will have to be a branch track built, and a ‘switch-back’ up the hill."1873, Mark Twain [pseudonym; Samuel Langhorne Clemens], Charles Dudley Warner, chapter XLIX, in The Gilded Age: A Tale of To-day, Hartford, Conn.: American Publishing Company, published 1874, →OCLC, page 445:
Marriage was the switchback, the giant racer, the lobster teas, the guarantee that one would never be alone.1934, Graham Greene, chapter 4, in It’s a Battlefield, library edition, London: William Heinemann, published 1959, →OCLC, page 171:
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Rail transport, Railways, TransportFiguratively, Often A railway track on which there are steep ascents and descents, a train moving partially or fully by the force of gravity using the momentum generated when descending to travel up an ascending part of the track; especially (UK, dated), such a track built for fun rides at an amusement park; a type of rollercoaster.
The WR faction claims that the Westbury route is better adapted to high speed, to which advocates of the SR route are apt to retort that the effect of modern diesel traction on schedules over the Salisbury–Exeter switchback has yet to be measured (the speed potential between Waterloo and Salisbury is scarcely disputable) […]1964 March, “News and comment: Which way to the west?”, in Modern Railways, Shepperton, Surrey: Ian Allan Publishing, page 147:
UK, Broadly, Figuratively, Often A path or road having a series of steep ascents and descents.
The switchback road to Diabaig - pronounced 'Jer-vague' - passes through some of the most exhilarating scenery in Scotland. […] With a final swoop, the road plummets down into Diabaig, where cottages are dotted across the slopes of a rocky semi-circle.1980, AA Book of British Villages, Drive Publications Ltd, page 151:
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Road, TransportCanada, US, Broadly, Figuratively, Often A sharp bend in a path or road which causes a traveller to almost reverse their direction of travel, especially one of a series of such bends on an incline; a hairpin bend; also a path or road having such a series of bends.
Already, we enter some airport bathrooms through a brief switchback of walls, so that we don’t ever grasp a door handle.2019 April 25, Samanth Subramanian, “Hand dryers v paper towels: the surprisingly dirty fight for the right to dry your hands”, in Katharine Viner, editor, The Guardian, London: Guardian News & Media, →ISSN, →OCLC, archived from the original on 21 Dec 2022:
Etymology The noun is derived from switch (“to turn (a train) from one railway track to another using a switch”, verb) + back (“so as to reverse direction and return”, adverb). The verb is derived from the noun.
1
Figuratively, Often To take a zigzag course or path.
I climbed 6,683-foot Velka Svistovka, not the highest mountain in the Tatras but arguably the one with the best view. I started from Zelene pleso chata (pleso means "lake" and chata means "hut" in Slovak), and right after turning the first corner I started switchbacking.2015 June 25, John Henderson, “A secret range of stunning mountains? Hikers, meet Slovakia’s High Tatras”, in Los Angeles Times, Los Angeles, Calif.: Los Angeles Times Communications, →ISSN, →OCLC, archived from the original on 06 Aug 2021: