HALF CAB
One-person cab usually located beside engine.
HALO MOLDINGS
Moldings that finish the edges of a vinyl roof
cover when it does not extend to the windshield, backlight and door openings.
HAND BRAKE
The brake apparatus used to manually apply the
brakes on a car or locomotive.
HAND HOLE
Opening in the disc area of a wheel for the purpose
of valve stem access to inside dual tire and chain application.
Hard Brake Count
The number of times a rapid deceleration of the vehicle had occurred on a trip (default hard brake threshold is 7mph/s Detroit, 9 MPH Cummins, default 0 CAT, Mack owner selectable). ( Detroit )
Hard Brake Limit
ProDriver setup parameter for the deceleration threshold to trigger a hard brake incident. ( Detroit )
Hard Braking
Latest hard braking incidents recorded up to five Incidents total ( Detroit )
The parts of the interior which are not soft trim;
I.e., ornaments, garnish moldings, script, appliques, etc.
HARDTAIL
Terminology used to describe a rear axle and wheel
support without springs or shock absorbers.
HARDTOP
A term applied to any fixed roof with retracting
window glass and no exposed "B" or middle pillar.
HARSHNESS
The high frequency (25-100 Hz) vibrations of the
structure and/or components that are perceived tactually and/or audibly.
HATCHBACK
Body styling where the backlight is included in the
deck lid or luggage compartment door.
HATCHING
Shading consisting of closely spaced parallel lines
in a drawing, vertically, horizontally, or diagonally.
HAZARD
See situation hazard.
HEAD END
Beginning or forward portion of any train.
HEAD MAN
Brake man responsible for work done in connection
with the forward section of the train and, when in transit, is stationed in the
locomotive.
HEADER
The structural member above the windshield at the
juncture with the forward edge of the roof panel.
HEADING ANGLE
The angle between the trace on the X-Y plane of the
vehicle x-axis and the X-axis of the earth-fixed axis system.
HEADLINER
The ceiling inside a vehicle, usually vinyl but
sometimes cloth, or one piece processed panel board.
HEAT EXCHANGER
Radiator-type device for cooling self-contained
fluid such as oil or water.
HEAT SHIELD
A protective guard to prevent air cushion material
burn-through.
HEAT TREATMENT
The process of heating and cooling a metal
throughout a temperature range for the purpose of obtaining certain desired
mechanical or physical properties.
HEATER (switch)
A device for melting snow at switches by means of
steam, an electric current, gas jets or oil.
HEATER CAR
An insulted box car equipped with heating apparatus
for the protection of perishables.
HEAVY TRUCK
Includes 1) single unit truck with GVW greater than
26,000 pounds., 2)tractor trailer combinations, 3) trucks with cargo trailers
and 4) truck tractor pulling no trailer.
HEEL-HARD
The point directly beneath the heel of the right
foot of the manikin on the normal metal floor surface.
HELPER
The auxiliary engine on a double-header.
HELPER SPRING
Additional spring device permitting great load on
axle.
HEM FLANGE
Metal joint formed by wrapping the outer metal
sheet of a door, hood or decklid around the inner panel.
HERTZ
Unit of frequency equal to one cycle per second.
HIGH CUBE
A truck or trailer body with above-average cubic
volume.
HIGH IRON
(slang) Main line or high track of a system of main
line tracks.
HIGH RAIL
The outer or elevated rail of a curved track.
HIGH SIDE
A motorcycle up set condition that involves an
extreme rolling and overturning motion of the motorcycle, where the upper part
of the motorcycle leans laterally towards the direction of travel.
HIGH SIDE GONDOLA CAR
A gondola car with sides and ends over 36 inches
high.
HIGHBALL
(slang) A
signal given to proceed at maximum authorized speed.
Highest RPM
The highest Engine Speed reached on a Trip. ( Detroit )
Highest Speed
The highest Vehicle Speed reached during a Trip. ( Detroit )
HIGHLIGHT
Theoretically a path of light described by the
intersection of curved surface and a line or plane becoming tangent to that
surface at a constant angle usually 45 degrees.
HIGHWAY
The entire width between the boundary line of every
way publicly maintained when any part thereof is open to the use of the public
for the purpose of vehicular travel; "a street; a publicly maintained
traffic-way.
HIGHWAY PEGS
An after market device mounted to the engine guards
or frame of a motorcycle for use as an additional foot rest by the operator.
HIGHWAY USER FEE OR TAX
A charge levied on persons or organizations based
on the use of public roads. Funds collected are usually applied toward highway
construction, reconstruction and maintenance. Examples include vehicle
registration fees, fuel taxes, and weight-distance taxes.
HINGE LIMIT LINES
The limits within which styling may vary body
surface without requiring new hinges or door hardware.
HIT-AND-RUN
See evading responsibilities.
HITCH, AIR
A trailer-to-dolly hitch mechanism where all slack
is taken up by admission of air to a suitable air chamber equipped mechanism.
HMTA
Hazardous Material Transportation Act
HOB
An engraved metal cavity, or female mold, from
which pressings are made.
HOG
(slang) Locomotive.
HOG OUT
The cut from solid stock.
HOGGER or HOG HEAD
(slang) Locomotive engineer.
HOLD OPEN
A device to hold the door in an open position.
Present production used an arrangement of spring and cam on the door hinges.
HOLD TRACK
A track on which cars are held awaiting
disposition.
HOLE
(slang) Passing track enabling one train to pass
another.
HOLLOMAN TESTS
Human volunteer tests of the ACRS on the daisy sled
at Holloman Air Force Base, New Mexico.
HOME
A location where a car is on the tracks of its
owner.
HOME CAR
A car on the tracks of its owner.
HOME JUNCTION
A junction with the home road.
HOME ROAD
The owning road of a railroad car.
HOME ROUTE
The return route of a foreign empty car to the
owning road.
HOME SIGNAL
A fixed signal at the entrance to an interlocking
block to govern trains or engines entering and using that block.
HOOD
(Bonnet) A hinged panel providing access to the
engine compartment.
HOOK
(slang) A crane used in wreck train service. Also called "Big Hook" or
"Wrecker".
HOP
The vertical oscillatory motion of a wheel between
the road surface and the sprung mass.
HOPPER
An open top car or trailer with one or more pockets
or hoppers opening on the under side of the unit to permit quick unloading of
bulk commodities.
HOP-UP
An upward change of direction of a surface or line.
HORIZONTAL BODY
ZERO LINE
Established in the initial design stages as the
base reference line for the horizontal lines of the body grid.
HORN
An air or electric powered device for producing a
sound for signaling.
HORSEPOWER (hp)
A measure of mechanical power or the rate at which
work is done. One horsepower equals
33,000 ft/lbs. Of work per minute. It
is the power required to raise 33,000 pounds one foot in one minute.
HORSEPOWER, BRAKE (bhp)
Maximum power available from an engine as measured
by a dynamometer.
HORSEPOWER, FRICTION(fhp)
Power required to drive the engine as equipped
during power test.
HORSEPOWER, GROSS
The brake hp determined under conditions defined by
dynamometer test of the stripped engine, that it, the brake horsepower of the
engine with only those accessories and attachments necessary to the functioning
of the engine during test.
HORSEPOWER, INDICATED(ihp)
Power developed in the cylinders and equal to the
sum of the brake horsepower and the friction horsepower.
HORSEPOWER, NET
The brake horsepower delivered to the clutch, or
its equivalent, with all accessories and attachments functioning (including
exhaust pipe, muffler and tail pipe) which are standard or regular equipment on
the engine as installed in the particular chassis.
HORSEPOWER, SAE (NACC)
Power rating for licensing purposes where: hp = (B2 x N)/2.5. B = Bore of engine N = No. of cylinders
HOSTLER
A fireman who operates light engines in designated
engine house territory and works under the direction of the engine house
foreman.
HOSTLER'S CONTROL
A simplified throttle provided to move the
"B" unit of a Diesel Locomotive not equipped with a regular
engineer's control.
HOT BOX
An over heated journal caused by excessive friction
between bearing and journal, lack of lubricant or foreign matter.
HOT BOX DETECTOR
A wayside infer red sensing instrument for
determining journal temperatures.
HOT DEVELOPMENT
The development of a pattern blank by trial error
cutting of blanks, using the form and flange dies in conjunction with the
checking fixture. This method is more accurate than a cold development.
HOT SHOCK
A ductile tungsten lamp filament, stretched, uncoiled,
bowed or tangled. Caused by the
inertial force of a collision
HOTCHKISS DRIVE
Rear axle drive where driving force, thrust and
torque, are transmitted from the rear axle to the frame through the rear
springs.
"H" POINT
The pivot center of "Oscar's" (manikin)
torso and thighs.
"H" TO HEEL
Distance in inches from "H" point to
accelerator heel point.
HUB CAP
A bright, decorative, circular metal disc covering
the hub of the wheel, lug nuts, etc. (See disc and wheelcover)
HUB MOUNT WHEEL
Wheels that are designed to center on the hub at
the bore of the wheel. These wheels generally have straight-through bolt holes,
since the bolt holes only supply clearance for the stud. Hub mount wheels are
used with two-piece flange nuts.
HUMP
An incline in a railroad yard over which cars are
uncoupled and allowed to roll free into a classification yard.
HUNGRY HORSE
Wire carrier read through.
HY-CUBE CAR
A boxcar of approximately 85 ft. Length and 10,000
cu ft. Capacity designed for hauling automobile body stampings and other
low-density freight.
HYDRAULIC BRAKE SYSTEM
A hydraulic brake system is a system that uses
hydraulic fluid as a medium for transmitting force from a service brake control
to the service brake, and that may incorporate a brake power assist unit, or a
brake power unit.
HYDROMETER
An instrument used to test the specific gravity of
battery fluid to determine the charge.
HYDRO-PLANNING
Hydroplaning occurs when tires rolling on the wet
surface of road reach speed where the tire becomes completely detached from the
road and skis along on a thin film of water.
HYPOID GEAR
Gear with diagonally positioned teeth.
HYPOTENUSE
The hypotenuse of a right triangle is the longest,
or diagonal side of the triangle
References
Detroit Diesel
Caterpillar User's Manual