R & R
(Repeatability
and Reproducibility) refers to gauge and test equipment studies. Repeatability
is the measurement variation obtained when one person measures the same
dimension or characteristic several times with the same gauge or test
equipment. Reproducibility is the variation in measurement averages when more
than one person measures the same dimension or characteristic using the same
measuring instrument.
R/100
Number of Repairs per 100 Vehicles
RABBET
An offset designed into the surrounding body
construction to accommodate and assemble glass.
RACER
Redbook Assumption Cost Estimating Request
RACK AND PINION GEARBOX
In a rack and pinion gearbox, the Steering shaft is
connected to a Sear, or pinion, and the pinion causes a rack (a type of
"straight sear") to move the steering linkage In this type of gearbox, the rack performs
the same function as the pit man arm.
RADIAL
The term "radial' refers to a direction toward
or away from the center of a circle (alerts a radius). Tire construction where
cords run at a 90-degree angle to the bead or the tire's direction of rotation.
"Radial" has come to mean the more modern of the two basic tire
types.
RADIAL PLY TIRE
A radial ply tire is a pneumatic tire in which the
ply cords which extend to the beads are laid at substantially 90 degrees to the
centerline of the tread.
RADIO CONTROLLED ENGINE
An unmanned engine situated within the train
consist, separated by cars from the lead unit, but controlled from it by radio
signals.
RADIUS
(r): The
distance from the center of a circle to a point on the circumference.
RADIUS RODS
Metal arms attached to frame and axles for
alignment.
RAIL
A length of track, usually thirty nine feet
long. Also see track.
RAIL BOND
An electrical conductor for bridging joints between
rails for the purpose of carrying electrical current and part of a track
circuit.
RAIL JOINT
A fastening designed to unite a butting ends of
rails.
RAIN CAP
Protection device used on exhaust stacks to prevent
rain entry when the engine is stopped.
Opens and closes automatically.
Opens by the pressure of exhaust gases passing out of the stack. When exhaust stops (with engine shut off),
the Ian cap closes.
RAKE
The angle formed by the intersection of the steered
axis and a vertical line while the motorcycle is in an up right position.
RAMP ANGLE
Angle created by lines tangent to the static loaded
radii of front and rear wheels, converging at the point of lowest ground
interference of underside of car - angle of overhang at lower extremities.
RANDOM VIBRATION
Random vibration exists in a system when the
oscillation is sustained but irregular both as to period and amplitude.
RATCHET
A serrated edge like that of a saw, sometimes
straight and sometimes on a wheel, into which a pawl engages, for producing or
(more commonly) restraining motion. See
brake ratchet, and pawl.
RATE OF CASTER CHANGE
The change in caster angle per unit vertical
displacement of the wheel center relative to the sprung mass.
RATE OF CHAMBER CHANGE
The change of camber angle per unit vertical
displacement of the wheel center relative to the sprung mass.
RATE OF TRACK CHANGE
The change in wheel track per unit vertical
displacement of both wheel centers in the same direction relative to the sprung
mass.
RATED HORSEPOWER
The maximum brake horsepower output of an engine as
certified by the manufacturer.
RATED TORQUE
The maximum torque produced by an engine as
certified by the manufacturer.
RATIO
Relation or proportion in magnitude of one quantity
to another.
REACTION
A person's voluntary or involuntary response to a
hazard or other situation that has been perceived; the response to a sensory
stimulus. Reactions may be reflex,
simple, complex, or discriminatory.
REACTION DISTANCE
The distance moved or traveled by a vehicle or
other traffic unit during reaction time.
REACTION PLATE
A backing plate for air cushion deployment.
REACTION TIME
The delay between the perception of a danger and
the beginning of the physical response to that perception.
REAR END BAR FIXTURE
Fixture used to locate rear end panel in body
frame.
REAR FACING
A seat oriented so that its occupant faces the rear
of the vehicle.
REAR OF A SIGNAL
The side of the Signal from which the indication is
received.
REAR QUARTER PANEL
The rear fender panel.
REAR QUARTER WINDOW
The rearmost side window located in the rear
quarter panel.
REAR SEAT RISER
The rise in the rear floor pan that supports the
front edge of the rear seat.
REAR-END COLLISION
See same-direction collision.
REBOUND
The relative displacement of the sprung and
unsprung masses in a suspension system in which the distance between the masses
increases from that at static condition.
REBOUND CLEARANCE
The maximum displacement in rebound of the sprung
mass relative to the wheel center permitted by the suspension system, from the
normal load position.
REBOUND STOP
An elastic member which increases the wheel rate
toward the end of the rebound travel. The rebound stop may also act to limit
the rebound travel.
REBOUND VELOCITY
The return velocity of the occupant after impact
with, and reaction to, the air cushion or vehicle interior.
RECEIVING TRACK
A track used for arriving trains.
RECOIL
The raising of a surface adjacent to a flange as a
result of the resistance of the material to the flanging process.
RECORD MODEL
A fiberglass or plaster reproduction of the original
clay model as approved.
Record Type
Identifies the type of data record in a Comma Delimited (CSV) export file. ( Detroit )
RED BOARD
A fixed signal to stop. Also see board.
REDBOOK
Part I: A publication generated by the Greenbook, but data is further enhanced
by preliminary drawings based on studio clay models representing a carline
approved concept or theme. Part II:
Additional stage of the initial Redbook developed from data after the
"hard point" of given components are finalized in design, thus
allowing the controllers offices to accurately define a vehicle cost and profit
margin.
REDUCED SPEED
Prepare to stop short of train or obstruction.
REDUCTION OF GEARS
Used where very slow speed is needed. Two reductions are made in the
differential. See gear ratio.
REEFER
Truck with heavily insulated refrigerated body.
REFERENCE LINE
A line, often the edge of a roadway, from which
measurements are made to locate spots, especially spots along a roadway.
REFERENCE POINT
A point from which measurements are made to locate
spots in an area; sometimes the intersection of two reference lines; (RP). A reference point is described in terms of
its relation to permanent landmarks.
REFINING IN TRANSIT
The stopping of shipments of sugar, oil, etc., at a
point located between the points of origin and destination to be refined.
REFLEX REACTION
An involuntary response to a stimulus; an
instinctive act resulting from perception of an imminently hazardous situation.
REFRIGERATED CAR / TRAILER
An insulated car, van-type truck or trailer body
equipped with a refrigeration unit.
Used for carrying perishable goods.
Also called a reefer.
REGROOVE
To cut new grooves into a tire. This can be done only on tires that are made
specifically to be regrooved. They are
marked "regroovable."
REGULAR TRAIN
A train authorized by a time table schedule.
REGULATOR
Instrument to control voltage and current in
vehicle electrical system.
RELATIVE ERROR
The ratio of the absolute error to the size of the
quantity.
RELATIVE POLAR MEASUREMENTS
A point on a drawing specified in terms of radius
and angle from the previous point.
RELATIVE X-Y COORDINATE MEASUREMENTS
A point on a drawing specified in terms of X- Y-
offset from the previous point.
RELAY EMERGENCY VALVE
A combination valve in an air brake system, which
controls brake application and which also provides for automatic trailer brake
application should the trailer become disconnected from the towing vehicle.
RELAY LOGIC SEQUENCING MODULE
An electro-mechanical device employing relays and
associated timing, protection and control components which provides logical
control of the ignition interlock system.
RELAY VALVE
Valve used to speed up the application and release
of the rear wheel brakes.
RELEASE COCK
See release valve.
RELEASE ROD
A small iron rod generally located at the side of a
car for the purpose of operating the air brake release valve.
RELEASE VALVE (air brake)
A valve attached to the auxiliary reservoir for
reducing the air pressure when the locomotive is detached so as to release the
brakes.
REMOTE UNIT
See radio controlled engine.
RENDERING
A detailed illustration.
REPAIR TRACK
A track used for car repairs.
Report Date
Date of generated report. ( Detroit )
REPORTING
Basis data collection to identify and classify a
motor vehicle traffic accident and the persons, property and planned movements
involved. Only strictly factual
information is wanted, no opinions.
Level 1 of traffic accident investigation.
RESERVOIR (air brake)
A cylindrical container for the storage of air
under pressure. Main reservoir of large
capacity are located in locomotives and under all motor cars having air
compressors; auxiliary and emergency reservoirs are located under the cars.
Reset Lockout
Prevents the Pro Link Diagnostic Data Reader from resetting DDEC Trip information. Without this lockout feature, trip data can be accidentally erased when a Pro Link is used to service the DDEC ECM. ( Detroit )
RESIN
A plastic liquid chemical. The two most commonly
used are epoxy and polyester.
RESISTANCE
Opposition to the free flow of electrical current
in a circuit.
RESISTOR
Any device that "uses up" voltage by
opposing, or resisting, the flow of electrical current. Resistors may be current consuming devices
such as lamps or motors, or devices which are designed for the purpose of using
a specific amount of voltage.
RESONANCE
A forced vibration phenomenon which exits if any
small change in frequency of the applied force causes a decrease in the
amplitude of the vibrating system.
RESONANT FREQUENCY
Frequency at which resonance exists.
RESTART
A feature of the ignition interlock system which
after starting allows uninhibited restart, regardless of the belt condition as long
as the driver remains seated.
RESTRAINT SURVIVAL DISTANCE (RSD)
The distance between a restrained vehicle occupant
in the normal, seated position and the interior surfaces of the vehicle in the
direction of the crash forces. When the
vehicle slows to a stop during impact it achieves its total deceleration during
the crush. Thus all slowing will take
place over the time required to produce the dynamic crush. The restrained occupant will not begin to
slow at the same time as the vehicle due to the slack in the restraint
system. The occupant will keep moving
at the pre-crash velocity as the vehicle begins to slow until all the slack and
stretch is eliminated from the restraint system. The restraint system will then hold the occupant back and cause
him to slow down. If the slack in the
restraint is removed before the vehicle comes to a complete stop, then the
occupant will be able to slow along with the vehicle during ride down.
RESTRAINT SYSTEM
Manually operated restraint system including
shoulder belts, lap belts, lap and shoulder belt combinations, or child safety
seats. Automatic restraint systems
include a relatively small number of "passive" belts and air cushion
systems.
RESTRAINT SYSTEM LOADING
The process of engaging the restraint system,
removing slack from the restraint system, and having the restraint system apply
a restraining force to the vehicle occupant.
RESTRICTED ARTICLES
Types of freight that cannot be handled at all or
may only be handled under certain specific conditions.
RESTRICTED SPEED
Proceed prepared to stop short of train,
obstruction, or switch not properly lined, looking out for broken rail not
exceeding fifteen mile per hour.
RESULTANT AIR VELOCITY
resultant air velocity vector is the vector
difference of the ambient wind velocity vector and the projection of the
velocity vector of the vehicle on the X-Y plane.
RESULTANT FORCE
A resultant force is that force which is due to the
vector summation of two or more forces.
With respect to accident reconstruction the forces acting on colliding
vehicles can be combined to give a single resultant force.
RESULTANT VECTOR
That single vector which would display the same effect as a number of original vectors added together.
RETAINING VALVE
A small manually positioned valve located near the
brake wheel for retaining part of the brake cylinder pressure, to aid in
retarding the acceleration of a train in descending long grades.
RETARDER
A metal grip adjacent to the rail, usually operated
by compressed air or electrical motors, for regulating speed of a car by
pressure on the wheels while rolling down a hump incline.
RETRACTOR LOCKING
A belt retractor which automatically locks after
the belt has been extended, preventing any further extension.
RETRACTOR VEHICLE SENSITIVE
A belt retractor which automatically locks when the
acceleration of the belt relative to the vehicle exceeds a predetermined level.
RETROGRADE AMNESIA
A loss or impairment of memory of events preceding
injury. In a traffic accident, a person
who has been unconscious for a considerable time or who has lost much blood at
the scene or the person may have no recollection of events immediately
preceding the crash.
REVERSE LEVER
The lever which controls the direction of motion of
the locomotive by reversing the traction motor field connections.
REVISED OCCUPANT SIMULATION
(ROS) A graphic computer simulation of occupant
kinematics applied decelerations.
REVOLUTIONS PER MINUTE
The number of turns or rotations the engine makes
in a minute (abbreviated RPM). Engine
RPM is expressed in hundreds on the tachometer.
REWORK
The act of incorporating a change or correction in
a production part by hand and or temporary tools.
REWORK SUMMARY
Information summary to assembly plants pertaining to
rework required on production parts.
RFI
Radio Frequency Interference.
RIDE
The low frequency (up to 5 Hz) vibrations of the
sprung mass as a rigid body.
RIDE CLEARANCE
The maximum displacement in compression of the
sprung mass relative to the wheel center permitted by the suspension system,
from the normal load position.
RIDE DOWN
The slowing of the vehicle occupant that occurs
while the vehicle is still being crushed in an impact. An unrestrained occupant will typically not
experience ride down. For a restrained
occupant, the amount of ride down achieved is determined by the time required
to fully load the restraint system.
RIDE RATE
The change of wheel load, at the center of tire
contact, per unit vertical displacement of the sprung mass relative to the
ground at a specified load.
RIG
Truck or truck-trailer combination.
RIGHT ANGLE COLLISION
In a right angle collision one vehicle is
perpendicular to the other when the collision occurs.
RIGHT OF WAY (RR)
The property owned by the railroad over which
tracks have been laid.
RIM
The item that supports the tire. It may consist of
one piece (tubeless drop center type) or two or three pieces (tube type).
RIM DIAMETER
The diameter at the intersection of the bead seat
and the flange. (See Tire and Rim
Association Year Book.) Nominal rim
diameter (i.e., 14, 14, 16.5, etc.) is commonly used.
RIM PULL
Actual amount of effort in pounds available at
point of contact of tire and road surface.
RIM WIDTH
The distance between the inside surfaces or the rim
flanges. (See Tire and Rim Association
Year Book.)
RIP
Car in need of repair.
RIP STOP
A fabric construction for air cushions with intermittent reinforcement.
ROAD
The part of a trafficway which includes both the
roadway, which is the traveled part, and any shoulder alongside the
roadway. Where there are unmountable
curbs, the road and roadway are the same.
If there is a guardrail, the road is considered to extend to the
guardrail.
ROAD BED
The foundation on which the track and ballast rest;
or on which the highway rest.
ROAD, SECONDARY
Not a main road or highway. Usually narrower, less direct, and often
more winding than a primary road.
ROADSIDE
That part of the highway not occupied by road or sidewalk.
ROADWAY
The part of the road intended for vehicle
travel. It does not include paved or
otherwise improved shoulders or what is sometimes called a berm or breakdown
lane.
ROBOGATE
A single tool body framing system employing
automatic locating and clamping fixtures with robots performing welding
operations to create dimensional control of the total body.
ROBOTS
A reprogrammable, multi-functional manipulator used
to position parts, tools, or welding guns through a variety of programmed
motions.
ROCKER PANEL
The sheet metal surface below the door opening,
running between front and rear wheel openings.
ROLL
The motion of a vehicle which has been retarded at
the ground level while the remainder of the vehicle continues moving forward
without leaving the ground; rollover.
One of the three principles axis of a vehicle; along the longitudinal
(x), axis.
ROLL AXIS
The line joining the front and rear roll centers.
ROLL CAMBER
The camber displacements of a wheel resulting from
suspension roll.
ROLL CAMBER COEFFICIENT
The rate of change in wheel inclination angle with
respect to change in suspension roll angle.
ROLL CENTER
The point in the transverse vertical plane through
any pair of wheel centers at which lateral forces may be applied to the sprung
mass without producing suspension roll.
ROLL FORMING
The continuous bend-forming of constant section
parts.
ROLL OVERSTEER
Roll steer which decreases vehicle understeer or
increases vehicle oversteer.
ROLL STEER COEFFICIENT
The rate of change in roll steer with respect to
change in suspension roll angle at a given trim.
ROLL STIFFNESS DISTRIBUTION
The distribution of the vehicle roll stiffness
between front and rear suspension expressed as percentage of the vehicle roll
stiffness.
ROLL TOP
A truck or trailer body with a sliding roof to
permit overhead crane loading of freight.
ROLL UNDERSTEER
Roll steer which decreases vehicle understeer with
respect to change in suspension roll angle at a given trim.
ROLL VELOCITY
roll velocity (p)
The angular velocity about the x-axis.
ROLLER BEARING
The general term applied to a group of journal
bearings which depend upon the action of a set of rollers in order to reduce
rotational friction.
ROLLING MOMENT COEFFICIENT
(C M x) is
based on the rolling moment deriving from the distribution of aerodynamic
forces acting on the vehicle.
ROLLING MOMENT
(Mx) is the
component of the moment vector tending to rotate the vehicle about the x-axis,
positive clockwise when looking in the positive direction of the x-axis.
ROLLING RADIUS
1) Diameter of a tire under the weight of a car. 2)
Distance from center of the tire to ground.
ROLLING RESISTANCE
The horizontal force required to keep a vehicle in
motion on a level surface, with the engine disconnected from the wheels and
with no brake application; drag factor produced by friction within the vehicle
and deformation of the tires and road surface.
ROLLOVER
An accident situation where the vehicle rolls at
least 90 degrees. The term rollover is
also sometimes used to describe a pitchroll.
See roll.
ROLLOVER TEST
A dynamic test used to evaluate body roof crush and
occupant anti-ejection characteristics.
ROLLOVER THRESHOLD
The lateral acceleration rate to which a vehicle
will begin rotation about its longitudinal axis.
ROOF DITCH
Body seam (joint) where the roof panel and body
side panel are welded together. This seam (joint) creates a ditch along each
side of the roof.
ROOF VAULT
The kinematics of the impacted pedestrian where the
head and torso pivot down toward the hood and the legs rotate up over the
torso. The pedestrian then flips up and
over the roof of the vehicle falling to the ground behind the vehicle.
ROPING
A term associated with uni-axial forming and
designating furrows of excess metal resulting from unequal wrap dimensions
at adjacent areas on the punch.
ROTARY MOTION
The equations of motion relating distance,
velocity, time and acceleration in a linear system have their exact equivalents
in rotary motion. These are angular
displacement (degrees or radians), angular velocity and angular acceleration.
The equivalent of mass when rotation is occurring is more complex however. It is the moment of inertia. Consider a uniform rod in comparison to a
dumbbell. Each is the same weight but the distribution of that weight is
different. If both objects are rotating
about their geometric centers at the same speed, they clearly have different
moments of inertia as a result of the different distributions of weight. The moment of inertia can be measured or
calculated for all objects and that parameter (I) replaces mass in calculations
involving angular equations. These are
equations relating to angular momentum and energy of rotation.
ROTOR
A metal disc used in a disc braking system. (See disc brakes).
ROUND HOUSE
A building, circular in design, used to house
engines while being serviced or repaired.
ROUTE
1) The course or direction that a shipment moves.
2) To designate the course or direction a shipment shall move.
ROVING
Chopped fiberglass.
RPM
Revolutions Per Minute, a measure of the engine
crankshaft rotational speed per minute.
RPM DROP
Drop in rpm between shifts in transmission.
RPM Limit
Engine overspeed limit in Revolutions Per Minute. ( Detroit )
RPO
Regular Production Option
RPS
Request for Procurement Services
RS
(Reliability Standard) specification of the
supplemental requirements that both internal production run and model year
production run parts must meet to conform to specifications. (Chrysler derived)
RULE "G"
A railroad operating rule prohibiting the
possession or use of intoxicants or narcotics while on duty.
RUMP RAIL
A side slat on a single-deck stock car made heavier
than the usual slats. It is placed
about four feet above the floor to resist movement of cattle against the car
sides.
RUN OFF
Rivulets of liquid debris from a puddle area
flowing downhill toward soak-in at the edge of the pavement; frequently the
source of tire prints after a collision.
RUN OVER
The kinematics of the impacted pedestrian where the
pedestrian falls under the vehicle while the vehicle is still moving. This situation can also occur with vehicle
occupants or bicyclists who are ejected into the path of a moving vehicle.
RUNNING GEAR
A general term applied to and including the wheels,
axles, springs, axle boxes, frames and other carrying parts of a truck or
locomotive.
RUNNING LIGHTS
Same as clearance or marker lights. Set clearance lights.
RUNNING TRACK
1) A track designated in the time table upon which
movements may be made subject to prescribed signals and rules, or special
instructions. 2) A track reserved for movement through a yard.
RURAL
That area outside the boundaries of an urban area.
RUT
A depression
in soft or loose material, such as snow or dirt, made by a rolling tire.
RZEPPA UNIVERSALS JOINT
A disc-type constant-velocity joint.
References
Detroit Diesel
Caterpillar User's Manual