G

 

 

G FORCE

A "G Force" is an effective force owing to the acceleration of a body   It is often called an "inertia force," and in this sense, it means the force necessary to give the body the acceleration it has at any instant  Often, the "G Force" is given as a proportion of the weight of the body, so that, for example, a force of 1 G would equal the weight of the body;  (g):  A pure number indicating the amount of gravitational acceleration (g) acting  on an object because of position  or velocity. The acceleration factor (fa) due to gravity (g).

 

GAGE OF TRACK

The distance between the heads of the rails, measured at a point 5/8 inch below the top of rails.  Standard gage is 4' 8.5".  See board gage and narrow gage.

 

GANDY DANCER

(slang) Track laborer.

 

GANTRY CRANE

A stilted traveling crane supported on a bridge or trestle.  Trestle bents are constructed on wheels so the whole structure travels on a track laid on the ground or floor.

 

GAP SKID

A braking skid mark which is interrupted by release and reapplication of brakes or which terminates by release of brakes before collision.  Compare with skip skid.

 

GARNISH MOLDING

The upper molding on the door panel above the arm rest, usually metal, used as a retainer for the door trim panel. Also found on "A" pillars, roof rails and back light.

 

GAS STRUTS

(Gas Springs) Gas filled cylinder used in place of torque rods or mechanical spring to assist in lifting the engine compartment hoods or rear compartment lids, hatches or lift gates.

 

GATE

Switch.

 

GATEWAY

A point at which freight moving from one territory to another is interchanged between carriers.

 

GAWR

1) GAWR is an abbreviation for Gross Axle Weight Rating. 2) Lowest rated member from following components: tires, suspension, hubs/wheels, rims, bearings, beam and brakes.

 

GCW

Gross combination weight. Total weight of fully equipped tractor, trailer or trailers and payload.

GCWR

Manufacturer's rating for maximum allowable weight of truck or combination.

GEAR RATIO

The number of revolutions of a driving gear required to turn a driven gear through one complete revolution.  For a pair of gears the ration is found by dividing the number of teeth on the driven gear by the number of teeth on the driving gear.

 

GEAR RATIO, AXLE

Ratio of the speed of the propeller shaft to the speed of the rear axle shaft.

 

GEAR RATIO, FAST

Low numerical ratio as 3.00/1.00 (high speed).

 

GEAR RATIO, SLOW

High numerical ratio as 9.00/1.00 (low speed).

 

GEAR RATIO, TRANS.

Ratio of input shaft speed to the speed of output shaft.

 

GEAR SHIFT

The device by which the gears of the transmission are engaged and disengaged.

 

GEARED SPEED

Calculated speed.

 

GENERAL SERVICE CAR

Box, gondola, or flat car not designed for a specific commodity or shipper, without special equipment.

 

GENERATOR

Engine-driven accessory for changing mechanical energy into electrical energy.

 

GLAD HANDS

A separable mechanical connector used to join air line hoses when combination vehicles are coupled together.

 

GLARE

Glare is the adverse effect on driver visibility and/or comfort caused by light source(s) within the visual field that are sufficiently brighter that the luminance to which the eyes are adapted.

 

GLIDER

Truck that has been rebuilt, particularly component-wise.

 

GO HIGH

To climb to the top of freight cars for purposes of signaling or setting brakes.

 

GOAT

A yard switch engine; it usually butts cars around the yard.

 

GONDOLA CAR

A freight car with sides and ends, but without a top covering.  Gondola cars are sometimes distinguished as high side, low side, drop end, drop bottom and general service.

 

GORE

The area immediately behind the bifurcation of two roadways, bounded by the edges of those roadways; "the angle between two roadways where one roadway divides into two.

 

GOUGE

A pavement scar deep enough to be easily felt with the fingers; ship, chop, or groove.

 

GOVERNOR, AIR

Device for controlling air pressure.

 

GOVERNOR, ENGINE

Device to automatically control maximum rpm.

 

GRAB IRON

Steel bar attached to cars and engines as a hand hold.

 

GRADE

The change in elevation in unit distance in a specified direction along the center line of a roadway or the path of a vehicle; the difference in level of two points divided by the level distance between points.  Grades are designated in feet or meters of rise or fall per foot or meter of level distance or in rise or fall as a percent of the level distance.  Grade is positive (+) if the surface rises in the specified direction and negative (-) if it falls in that direction.

 

GRADEABILITY

Percent grade that a vehicle will negotiate.

 

GRADIENT (BRAKE PIPE)

The difference in brake pipe pressure between the front and rear of the train.  It is the direct result of leakage or train line obstruction.

 

GRADIENT FACTOR

Gradient factor is a measure of the grade of a slope  it is the vertical distance of the grade divided by the horizontal distance  Trigonometrically, the gradient factor is the tangent of the angle of the grade  Often, the gradient factor is expressed as the percent grade, the gradient factor multiplied by 100.

 

GRAIN DOOR

A partition placed across the door of a box car to prevent loss of grain by leaking.


Granular, granularity
Consisting of, or appearing to consist of, granules having a grainy texture. (Merriam- Webster's 10th Collegiate Dictionary) ( Detroit )

Granule
A small particle; esp.: one of numerous particles forming a larger unit. (Merriam- Webster's 10th Collegiate Dictionary) ( Detroit )

GRAVEL DEFLECTOR

A metal plate fitted between the front or rear bumper and the body.

 

GRAVITATIONAL ACCELERATION

(g):  The acceleration to a body moving only under the vertically directed force of gravity.  Taken as a constant for reconstruction purposes.  g = 32.2 ft/sec2 or g = 9.81 m/s2

 

GRAVITATIONAL CONSTANT

The gravitational constant is the ratio between the weight of a body (expressed in force units) and the mass of the body (expressed in mass units)   For example, if a body having one unit of mass is located on the surface of the earth, then it is in the gravitational field of the earth, and in English units it would weigh 32 2 pounds   Therefore, the gravitational constant on the surface of the earth is (very nearly) 32 2 ft sec2.

 

GREEN CAR

Environmentally friendly car

 

GREENHOUSE

The upper body of an automobile; the structure above the beltline - glass, roof and supporting members.

 

GRILLE

Screen or protective structure located in front of radiator.

 

GROOVE

A long, narrow, pavement gouge; a channel in the pavement made by a small, strong metal part being forced some distance along the surface while under great pressure.

 

GROOVES (TIRES)

Grooves are the spaces between two adjacent tread ribs

 

GROSS AXLE WEIGHT RATING

Gross axle weight rating is the value specified by the vehicle manufacturer as the load-carrying capacity of a single axle system, as measured at the tire-ground interfaces

 

GROSS BIOMECHANICS

The overall results of forces applied to a biological system  as a whole which defined the macroscopic response of the system.  For example, the overall motion of the arms, legs, torso, and head as a result of impact forces.

 

GROSS COMBINATION WEIGHT RATING

Gross combination weight rating is the value specified by the manufacturer as the loaded weight of a combination vehicle

 

GROSS CONTACT AREA

The total area enclosing the pattern of the tire tread in contact with a flat surface, including the area of grooves or voids.

 

GROSS NATIONAL PRODUCT

A measure of the money value of the goods and services becoming available to the nation from economic activity.

 

GROSS TON

2240 pounds.

 

GROSS TON MILE

The movement of a ton of transportation equipment and contents a distance of one mile.

 

GROSS VEHICLE WEIGHT

The total weight, including the weight of the base vehicle, all added equipment, driver and passengers, and all cargo loaded into or onto the vehicle.  Actual weight may be less than or greater than GVW.

 

GROSS VEHICLE WEIGHT RATING

The gross vehicle weight rating is the value specified by the manufacturer as the loaded weight of a single vehicle  GVWR is an abbreviation for Gross Vehicle Weight Rating

 

GTW

Gross train weight. Same as GCW.

 

GUN

Track torpedo used for signaling; also the injector of a locomotive.

 

GUSSETT

Flat steel or aluminum plates tying in cross-members to frame rails.

 

GVW

Gross Vehicle Weight. Total weight of fully equipped truck and payload.

 

GYPSY

An independent truck operator who drives his own truck and secures freight wherever he can or one who trip leases to authorized carriers.

 

References

Detroit Diesel

Caterpillar User's Manual