J
Jack	Locomotive. (A term often confused with the lifting device, hence seldom used). Most commonly, a "Juice Jack": electric locomotive.
Jacket	American term for outer covering of thin sheet steel over the lagging material of a locomotive boiler, cylinder or other insulated heat radiating surface.
Jackpot	Miscellaneous assortment of mail and parcels piled in the aisle of a postal car and requiring removal before the mail in the stalls can be "worked".
Jailhouse Spuds	Waffled potatoes.
Jam Buster	Assistant yardmaster.
Jam Nuts	Doughnuts.
Janney	To couple; derived from the Janney automatic coupler.
Jawbone Shack	Switch shanty.
Jay Rod	Clinker hook.
Jerk A Drink	Take water from track pan without stopping train. From this came the word jerkwater, which usually means a locality serving only to supply water to the engines of passing trains; a Place other than a regular stop, hence of minor importance as jerkwater town, jerkwater college, etc.
Jerk Soup	Same as jerk a drink.
Jerk-By	See flying switch.
Jerry	Section worker; sometimes applied to other laborers.
Jew Bar	Slang term for a device that holds a track in gauge. Used on sidings or industrial track.
Jewel	Journal brass.
Jigger	Full tonnage of "dead" freight.
Jimmies	Four-wheel coal or ore cars. Also known as "Jennies".
Jitney	1) Four-wheel electric truck that carries baggage around inside a terminal. 2) An unregulated private automobile that carried passengers on public highways for 5-cent fare in direct competition with trolley cars.
Johnson Bar	The reversing lever of a steam locomotive.
Join The Birds	Jump from moving engine or car, usually when a wreck is imminent.
Joint	1) A length of rail, generally 33 or 39 feet. 2) Making a joint: coupling cars. 3) Riding to a joint is bringing cars together so that they couple.
Joint Facilities	Any facilities owned by two or more railroads.
Joker	Independent or locomotive brake, part of E-T (engine-train) equipment.
Journal	The load-bearing part of a shaft or axle support by a bearing.
Journal Box	Metal box around axle bearing for holding a lubricant saturated pad next to the wheel bearing.
Journal Log	Compiled by the conductor, a list of the make-up and events of train movement.
Juggler	Member of way-freight crew who loads and unloads freight at station stops.
Juggling The Circle	Missing a train-order hoop.
Juice	Electrical power. A juice fan is one who makes a hobby out of electric railways.
Juice Jack	Straight-electric locomotive.
Junction	A location designated by the Timetable where two or more railroad lines converge.
Junk Pile	Old worn-out locomotive that is still in service.