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 )
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