derailer

derail +‎ -er. Doublet of derailleur.

derailer (plural derailers)

1. One who, or that which, derails.
   1. (rail transport) Synonym of derail: A device placed on railway tracks in order to cause a train to derail.
2. (cycling, uncommon) Alternative form of derailleur.
   • 2009, Louis G. Perez, “Society in the Twenty-First Century”, in The History of Japan (The Greenwood Histories of the Modern Nations), 2nd edition, Westport, Conn., London: Greenwood Press, →ISBN, page 202:

     Very few bicycles are of a different color or employ more gears with derailer sprockets and hand brakes.

   • 2009, Christine Elliott, David Jablonka, “Cycles Alex Singer”, in Custom Bicycles: A Passionate Pursuit, Images Publishing, →ISBN, page 72, column 2:

     Through sheer ingenuity and resourcefulness, these men handproduced parts such as derailers, stands, seat posts, cranks, fenders, and all manner of elements used in the production of a functional bicycle.

   • 2016, Erik Reece, Utopia Drive: A Road Trip Through America’s Most Radical Idea, New York, N.Y.: Farrar, Straus and Giroux, →ISBN, page 170:

     Inside, two bearded men are working on a busted fuel pump, and another is repairing a bicycle derailer.

   • [2016, Tony Hadland, Hans-Erhard Lessing, Bicycle Design: An Illustrated History, MIT Press, →ISBN, page 246:

     Recent American attempts to further Anglicize the word to “derailer” have met with little success. In any case, no rails are involved.]

• redialer, rerailed