Railroad Dictionary

Keeper	A latch-type device used to secure a switch in the desired position.
Key Train	Any train with: Five or more tank carloads of a poison inhalation hazard (PIH). Twenty or more tank carloads or intermodal portable tank loads of hazardous material, excluding mixed loads with "49501" as the first five digits of the STCC number. A CSXT computerized consist, if issued, will identify a "key train" which meets the qualifying criteria. Other trains not receiving a consist will be identified from the shipping descriptions whether or not they are "key trains."
Kick (Slang)	Applied to switching, kicking is the act of pushing a car or cars at speed ahead or behind an engine, and then cutting the car or cars loose from the engine while the brakes are applied quickly on the engine, thus allowing the car or cars to be kicked free.
Kicker (Slang)	See Dynamiter.
Kingpin	On a highway trailer, the short flanged steel pin which projects downward from the front load bearing surface of the underframe. The kingpin is grasped by the tractor in highway operation, or by the trailer hitch (fifth wheel) when the trailer is being transported on a piggyback flat car.
Knock-Down Stanchion	A moveable, vertical, support bar on which the front end of a trailer rests while being transported on a flat car. See also Fixed Stanchions.
Known Damage	Damage discovered before or at the time of delivery of a shipment.
Knuckle (Part of the Coupler)	The pivoting hook-like casting that fits into the head of a coupler and rotates about a vertical pin to either the open position or to the closed position. Coupler knuckles must conform to a standard dimensional contour specified by the Association of American Railroads.
Knuckle Pin	The pin holding the knuckle in the jaws of the coupler. Sometimes called pivot pin.
Knuckle Thrower	A device which throws the knuckle of a car coupler open when the uncoupling lever is operated.