Dictionary definition of “dead man’s switch”

dead man’s switch

n. especially in railroad usage, a safety device meant to stop or slow a vehicle or machine if its operator releases the controls. Also dead man’s handle, dead man’s brake, dead man’s lever, dead man’s pedal. Subjects: English, Automobiles & Transportation, Slang

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Citations: 1908 Washington Post Magazine (Jan. 19) “Precautions of Railroads to Prevent Death at the Throttle” (in New York) p. 1: On the subway and elevated lines it is found in the nearest doorman and a “dead man’s switch.” 1937 Andy Hamilton Los Angeles Times Sunday Magazine (June 20) “High For Streamliners” p. 11: Hardly noticeable, under his right foot, is a small pedal—resembling the clutch pedal on your automobile. “That’s called ‘dead man’s pedal’,” Charlie explains. “The weight of my foot holds it down. If for any reason my foot should be removed—in case of heart failure or if I should be thrown from the seat—the motors would be switched off and the brakes locked.” 1941 Herbert Chase New York Times (Aug. 3) “Suggestion for Relocation Of Accelerator Shows Many Plans Tried” p. XX5: Cars have been built with brake pedals.…We have built-in hand-braking controls and so-called “dead-man” brake controls. 1949 Marian McKay Chicago Defender (June 11) “Underground Pilots” p. 13: There is also a “dead man’s brake” to stop the train if anything happens to the motorman. 1978 Zuhair Kashmeri Globe and Mail (Toronto, Canada) (June 29) “Safety switch not on when train killed 3, Milton inquest told” p. P1: A safety switch was disconnected in a runaway locomotive which crushed three people to death in Milton on March 14, an inquest was told yesterday. The switch, called a dead man’s switch, first gives a warning whistle and then stops a moving train engine if the operator does not have his foot on the switch pedal. 1981 Edward A. Gargan New York Times (July 6) “Brakes Were Off On Subway Train Involved In Crash”: In the motorman’s cab there are two levers, a braking lever operated by the right hand and the controller lever, equivalent to an accelerator, which is operated by the left hand. The controller is also called the “dead man’s handle’” because it must constantly be pressed downward against a spring to accelerate the train. When the motorman’s hand is lifted from the lever, the lever springs upward and the train automatically brakes. 1996 Peter Luck Sun-Herald (Australia) (May 19) “Moving Right Along, Folks” p. 118: Having produced or presented most of Australia’s current affairs programs, with the occasional live disaster, I used to joke that we ought to have a “dead man’s lever” such as those on trains which would bring the program screeching to a halt if things got out of control. 2007 Britney Glaser KPLC-TV (Lake Charles, Lousiana) (July 4) “Behind-the-Scenes with Pyrotechnics”: This pyrotechnic crew won’t be sitting around, though, until the “dead man’s switch,” as it is called, is clicked to start the show. Until then, they’re moving boxes, cutting tape and sorting through thousands of fireworks.

Posted 5 Jul 07 | Permalink | Tell a Friend

Reader comments:

I’ve run across this term in print as ‘dead man switch’, with the ‘s’ sound believed, by the writer, only to be part of the word ‘switch’.

Interesting that almost all of these examples quote the phrase, and most formally explain it, assuming the reader is unfamiliar with the term, even though it’s been around for at least a hundred years, and obviously comes up fairly often in both in reporting and fiction.

The last usage seems to be incorrect, BTW. Surely there isn’t a member of the team sitting on a switch at all times? And if he dies, the fireworks show will automatically start? I don’t think so. I suspect the term the writer is looking for is ‘safety interlock’ or something similar, which is the opposite of a dead man switch.

But geez, it’s from a local TV news show, awfulness in both prose and fact-finding is a given.

by Slithy Tove 07 Jul 07, 0105 GMT

In 2004 there was a piece of freeware circulating called dead man’s switch, that would erase your harddrive at a specified time interval, unless you entered a password.

by degustibus 09 Jul 07, 0110 GMT