G
G.M. General manager. G.Y.M. is general yardmaster.
Galloper Locomotive, the iron horse.
Galloping Goose 1) An early (1910-1920's) rail bus, often a modified highway coach. Possibly named for a famous unit on the Rio Grande Southern. 2) A shaky section car.
Galvanizer Car inspector.
Gandy Dancer Track laborer. Name may have originated from the gander-like tremulations of a man tamping ties, or from the old Gandy Manufacturing Company of Chicago, which made tamping bars, claw bars, picks, and shovels.
Gangway Space between the rear cab post of a locomotive and her tender.
Gap A space between the rails to insulate one rail from the other. Used to prevent a short in a reverse loop, or to divide the layout into separate blocks or circuits for multiple train operation.
Garden Freight yard.
Garden Railroad A form of model railroading which is usually done outdoors. First started in Europe and now one of the fastest growing segments of model railroading world wide. Most Garden Railroads are built on "One Gauge" track which is 45mm. between the rails.
Gas House Yard office.
Gas Turbine A rotary internal combustion engine driven by expanding gases exerting force against vanes or similar structures mounted on a common shaft.
Gas-Electric A self-propelled car powered by a gasoline engine driving a generator which supplies current to motors on the axles. Gas-electrics were the common form of branch line passenger train in the 1920's and 1930's.
Gate Switch.
Gateway See Interchange Point.
Gauge The distance between the inside edges of the rail heads. Most  railroads in North America and Europe are built to a standard gauge of 4'- 8 1/2". Some gauges currently in use are;
Broad gauge Spain 1674 mm 5' 5 9/10th"
  Portugal 1665 mm 5' 5 11/20th"
  Ireland 1600 mm 5' 3"
  Finland 1524 mm 5' exactly
  former USSR 1520 mm 5'
       
Standard gauge USA 1435 mm 4' 8 1/2"
  Metric English Standard 1435 mm 4' 8-1/2"
       
Narrow Gauge North African Cape 1067 mm 3'6"
  meter gauge 1000 mm 3' 3 37/100"
  Colorado   970 mm 3'
  US narrow   914 mm 3' 0"
  Maine   630 mm 2'
  North Colorado Std.   485 mm 18"
  Min. Commercial   425 mm 15"
Gauntlet
1) Two sets of standard-gauge rails interleaved so that two otherwise separate lines can share a bridge or tunnel. 2) A switch with long closure rails, so that the points and frog can be on opposite sides of an obstacle such as a bridge. 3) A third set of rails placed in between two other sets of rails to carry wide loads through tunnels.
Gay Cat Tramp held in contempt by fellow vagrants because he is willing to work if a job comes along.
Geep Nickname for General Motors GP (General Purpose) locomotives.
General Yardmaster, abbreviated Y.M.
General Order (GO) A publication used to summarize changes to the Timetable and other instruction manuals. GO's contain revision pages for the Timetable, and are issued periodically by the designated officer.
Generator A device that changes mechanical energy to electrical energy.
Get The Rocking Chair Retire on a pension.
Get Your Head
Cut In		 Boomer slang for "wise up".
Girl or Old Girl Affectionate term for steam engine. The locomotive, like the sailing ship, is often called "she" instead of "it".
Give Her The Grit Use sand.
Glad Hand The metal coupling on the end of an air hose.
Glass Cars Passenger cars.
Glim Switchman's or trainman's lantern.
Glimmer Locomotive headlight.
Glory String of empty cars. Also death, especially by accident.
Glory Hunter Reckless, fast-running engineer.
Glory Road Sentimental term for railroad.
Go High Same as decorate.
Goat Slang expression for a locomotive, usually a small yard switcher.
Goat Feeder Yard fireman.
Gods Of Iron Huge, powerful locomotives.
Gomulka [SL] Class 311/315 Pafawag EMU. Notorious president's name for infamous and hated Polish hard-riding underground trainsets, misused here as commuter trains.
Gon Slang for gondola.
Gondola An open car with low sides for hauling items like lumber, steel and scrap. Also "bathtub gondolas", with higher sides for commodities like coal and gravel.
Gone Fishing Laid off.
Goods European term for general freight.
Goo-Goo Eye Locomotive with two firedoors.
Goose To make an emergency stop.
Goose Her Reverse a locomotive that is under headway.
Go-To-Hell Signal Signal given with violent motion of hand or lantern.
Goundhog A slang term for a promoted engineer with trainman seniority.
Governor Device for maintaining a constant engine crankshaft speed over long periods during which the load on the engine may vary.
GP General Purpose - 4 axle road switchers.
Grab Iron Handholds on the sides, ends, and roofs of cars.
Grabber Conductor of a passenger train. (He grabs tickets).
Grade The ratio of elevation gained or lost per distance traveled measured in feet, expressed as a percent "%". The base is 100 Ft. so a 1% grade represents a 1Ft. elevation change in 100Ft. of travel.
Light Grade = 1% or less.
Heavy Grade = 1% to 1.8% .
Mountain Grade = 1.8% or greater.
Cresting Grade = a long ascending grade that changes with enough magnitude to require a change in train handling procedures.
Grade Crossing When two tracks or a track and a road cross each other at the same level.
Grade Resistance Resistance that results from the energy put into a train to lift it vertically, as up a steep grade. The energy is returned without loss when the train comes back down again.
Grainer Rail slang for covered hoppers, which are often used to transport grain and other bulk, fluid solids.
Gramophone Obsolete term for telephone.
Grass Wagon Tourist car. (Tourists like scenery).
Grasshopper Old type of locomotive with vertical boiler and cylinders.
Grave-Digger Section man.
Graveyard Siding occupied by obsolete and disused engines and cars also scrap pile.
Graveyard Watch 12.01 A.M. to 8 A.M., or any midnight shift, so called because that shift includes the quietest hours of the day.
Gravity Yard A yard where gravity assists in the spotting and classifying of cars whereby they move along under their own momentum. Also called a Hump Yard.
Grazing Ticket Meal book.
Grease Monkey 1) An employee who is responsible for greasing frogs, switches and interlocking track equipment. 2) A car oiler.
Grease The Pig Oil the engine.
Greasy Spoon Railroad eating house. Menu is colloquially known as switch list, fork is hook, butter is grease pot, hotcakes are blind gaskets, and beans are torpedoes.
Green Eye A slang term for a clear signal.
Greenbacks Frogs for re-railing engines or cars.
Greenball Freight Fruit or vegetables.
Greenfield Outdoor conduit used by railroad.
Greetings From
The Ds		 Train orders from the dispatcher.
Griever Spokesman on grievance committee. Brotherhood or Union representative at an official investigation.
Grind Shay-geared engine.
Grip Trainman's suitcase.
Ground Throw A mechanical device (usually done manually) which will change the position of a turnout, and simultaneously change the position of the signal mounted on top of the ground throw.
Groundhog Brakeman, yardmaster, or switch engine.
Grunt Locomotive engineer. Traveling grunt is road foreman of engines (hogs). Grunt may also be a lineman's ground helper; grunting is working as a lineman's helper.
Gumshoe A railroad detective.
Gun 1) Torpedo, part of trainman's equipment; it is placed on the track as a signal to the engineer. 2) The injector on the locomotive that forces water from tank to boiler. 3) To gun means to control air-brake system from rear of train.
Gunboat Large steel car.
Gut Air hose. Guts is drawbar.
Gypsum Calcium sulfate used to make molding plaster, Hydrocal, and Plaster of Paris. These products are commonly used in model railroad scenery projects.