third rail
[thurd reyl]
- Railroads.
- a rail laid parallel and adjacent to the running rails of an electrified railroad to provide electric current to the motors of a car or locomotive through contact shoes.
- an additional running rail laid on the same ties as the two regular rails of a railroad track to provide a multigauge capability.
- a controversial topic or issue in the public sphere that people, especially politicians, try to avoid discussing (often used attributively): a third-rail subject;Doping is the third rail of the Olympics.Social Security is the third rail of American politics.
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Origin of third rail
An Americanism dating back to 1865–70
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for third rail
Contemporary Examples
And then there is the third-rail issue that is particularly electric in a state with so many retirees.
Marriage equality is not remotely the third-rail issue it is sometimes considered.
Historical Examples
They had traveled by the third-rail line twenty miles into the country.
The Crystal BallRoy J. Snell
He may perfect a third-rail system for use on moving trains.
The History of the TelephoneHerbert N. Casson
It was originally on the third-rail system, but was changed into an ordinary overhead trolley seven or eight years ago.
One Irish SummerWilliam Eleroy Curtis
A great rate of speed can be gained with the third-rail system, ten miles having been made in thirteen and a half minutes.
The third-rail system in its simplest form is shown in Fig. 29, which represents a section through the roadbed.
third rail
- an extra rail from which an electric train picks up current by means of a sliding collector to feed power to its motors
- US politics
- a cause or topic that is considered extremely dangerous for a person to support or comment on
- (as modifier)a third-rail issue
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Idioms and Phrases with third rail
third rail
Something that is dangerous to tamper with, as in Anything concerning veterans is a political third rail. This term alludes to the rail that supplies the high voltage powering an electric train, so called since 1918. On the other hand, grab hold of the third rail means “become energized.” Both shifts from the original meaning date from the late 1900s.
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The American Heritage® Idioms Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.