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- C -
Cant. Tilt or inclination, as the inward
inclination of a rail, accomplished by using canted tie plates. The undesirable
outward tilt of tie plates on sharp curves.
Capillary action. The process by which
water is drawn from a wet area to a dry area through the pores of a material.
Car, ballast. A car specially designed for
carrying and distributing ballast.
Car, Hand. A four-wheeled, hand operated
railroad work car for transporting men and tools.
Car, motor. A motor-driven railroad work or
Car, trailer or push. A four-wheeled
railroad work car designed to be pushed by hand or pulled by a motor car.
Catenary System. A system of wires
suspended between poles and bridges supporting overhead contact wires normally
energized with electricity.
Cattle guard. See Stock guard.
Check. A small lengthwise crack or
separation of wood fibers, caused by superficial shrinkage of a timber.
Chisel, track. A handled tool to be struck
by a sledge, for cutting rail by scoring the base and web until breakage occurs,
or for similar cutting. A rail cutter.
CTC-Centralized Traffic Control. The
manipulation of automatic and/or cab signals and power operated switches from a
central location where signals supersede the superiority of trains.
Circuit, track. A low-voltage flow of
electricity in the rails of a track when they are bonded at the joints and form
a complete circuit.
Catch basin. A receptacle, commonly
box-shaped and fitted with a grilled inlet and a pipe outlet drain designed to
collect rain water and debris from the surface and retain the solid material so
that it may be removed at intervals. Catch basins are usually installed at the
junction where several drain pipes join, beneath a bridge floor, or within the
approach roadway with a grilled inlet adjacent to the roadway curb.
Clip, switch. The device by which the
switch rod is jointed to the switch rail. It is usually united with the switch
rail by bolts or rivets. It sometimes has staggered bolt holes in the horizontal
leg for making detailed adjustments in positions of the switch rails.
Clip, transit (switch). A switch-rod clip
drilled with several holes in a line diagonal to the axis of the switch rod, for
effecting adjustments in the throw of the switch.
Closure rail. The lead rails connecting the
heels of a switch with the toe ends of a frog.
Coefficient of Thermal Expansion. The unit
strain produced in a material by a change of one degree in temperature.
Compression. An axle force or stress caused
by equal and opposite forces pushing at the ends of a member. In simple bending
it is also present above or below the neutral axis.
Compromise bars. Special joint bars to
connect rails of different section in such a way that the gage sides and the top
of the head and running surfaces are held in line. Also called offset bars.
Computer. An electric calculator capable of
receiving programmed data and interpreting, manipulating and storing the data.
The system is composed of (1) a card reader/punch which functions as an
input/output device, (2) a central processing unit (CPU) which is where the
actual computing is done, (3) a printer which is an output device, and (4) a
disc drive and (5) a plotter which can provide graphic display of program
output. Computers vary in size and speed of computation. Data storage varies
between disc, tape and drum types.
Contact (Trolley) Wire. The overhead wire,
sometimes referred to as trolley wire, which the pantograph of an electric
locomotive rides against (contacts) to collect its electrical current (source of
Crane, track. (Also called maintenance
crane.) A power-operated crane used principally for setting rails in track
renewal, but having many similar uses in maintenance work.
Crank, adjustable (switch stand). A switch
operating device by which the position of the mechanism at the base of the
spindle can be altered to adjust the switch.
Crank, breakable (switch
stand). A short
crank casting of soft metal, designed to break when the switch is run through
and therefore prevent damage to switch-point rails.
Creosote. An oily aromatic compound
distilled from tars, used in the preservation of wood exposed to the elements.
Crib. (1) The ballast or the open space
between two adjacent crossties, (2) A crisscross structure of logs, timber,
concrete or other members, used to retain a fill or as a bridge support.
Cross level. The distance one rail is above
or below another. This should not be confused with Superelevation on curves.
Crosstie. See Tie.
Crossing, grade (Xing). A crossing or
intersection of a railroad and a highway at the same level or grade.
Crossing protection. An arrangement of
signs or electric signaling devices designed to prevent accidents at grade
crossings. May include short arm gates.
Crossover. Two turnouts with the track
connecting their frogs, arranged to form a passage between two nearby and
generally parallel tracks.
Curvature, degree of. A measure of the
sharpness of a simple curve in which a 1deg. curve is taken as the central angle
subtended by a chord or arc of 100 feet and for which the radius is taken as
5,730 feet. Sharper curves are in direct proportion, i.e., a 10deg. curve is
taken as one having a radius of 573 feet. Railroads use the chord definition -
highways the arc of definition.
Curve, compound. A curve composed of two or
more simple curves which join on common tangent points or common easement curves
and which lead in the same general direction, i.e., to left or right, but each
with different radii.
Curve, easement. A curve, the degree of
which varies in some definitely determined manner to give a gradual transition
between a tangent and a simple curve or between two simple curves. Also called
spiral easement and transition spiral.
Curve, reverse. A curve composed of two
simple curves which join at a common tangent point or by a short tangent track
or a reverse easement curve, and bear in opposite directions, i.e., as to left
and right or vice versa.
Curve, simple. A curve in the form of an
arc of a circle usually described as to its degree of curvature.
Curve, vertical. A curve in the profile of
a track to connect intersecting grade lines and to permit safe and smooth
operation of trains over summits and across sags.
rail from heel of switch to toe of frog.
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- D -
Degree of curvature. See Curvature, degree
Depth, ballast. The depth from the bottom
of tie to top of sub ballast or sub grade. (The ballast between the ties (in the
cribs) is a part of the ballast section but its depth is not a part of the
specified ballast depth.)
Deenergized-Apparently Dead. Electric
apparatus, such as overhead wires, third rail, transformers, switches, motors,
etc., is deenergized when disconnected from the normal power source, but such
apparatus is dangerous to life until it is known to be properly grounded.
Derail. A track safety device to guide
rolling stock off the rails at a selected spot as a means of protection against
collisions or other accidents.
Derailment. Anytime the wheels of a car or
engine are off the head of the rail.
Dolly, rail or timber. A device consisting
of one or more wide rollers mounted in a frame, used as a platform and as a
truck for moving rail, long heavy timbers, and other items.
Drill, track. A machine designed to operate
horizontally to drill holes through webs of rails, especially for track bolts.
It may be a one man ratchet drill or a geared drill machine with a frame, rail
clamps, feed screw, high speed steel bit and chuck, and alternating crank
handles turned by two men otrack to another.
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Easement curve. See Curve, easement.
Electrified Territory. That portion of the
railroad consisting of main tracks, secondary tracks, sidings, yards and
industrial tracks equipped for electric train operation by catenary system or by
third rail and necessary substations, transmission and signal power lines
located above or adjacent to the tracks.
Elevation (of outer rail on curve). See
End post. The piece of an insulating joint
which separates the rail ends.
Energized-Live (Dangerous to
Life). Electric apparatus, such as overhead wires, third rail, transformers, switches,
motors, etc., is energized when connected to the normal power source. All
systems are considered to be energized until a qualified individual knows the
circuit has been de-energized.
Engine, Booster. Dating from the Superpower
steam engine days. The booster was located on the rear axle of the trailing
truck (usually) or the fore axle of the forward truck on the tender. Most
booster engines were built by the Franklin Steam Engine Co. Due to
the added weight of the larger grate area on the superpower steamers (after
about 1925, the Lima A-1 Berkshire being considered the first of that extended
family). this weight and the little steam traction engine driving the axle added
10-15,000 lbs additional tractive effort for starting up heavy freights ( they
could run up to about 25 mph).
Engine Burn. Destruction of rail head metal
caused by spinning locomotive wheels. Engine Burn Fracture is a rail break
caused by an engine burn.
inserted between ends of abutting rails while track is being laid to provide
allowance for expansion of steel when temperature changes.
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- F -
Fastener, tie-plate. A special tie-plate
long enough to support the bases of a guard rail and the adjacent running rail
and with a rail brace riveted to it for supporting the guard rail.
Fastenings, auxiliary track. Spring
washers, tie plates, rail braces, rail anchors and other accessories.
Fastenings, track. A term commonly applied
to splice bars, bolts and spikes.
Fill. (Filling). Material, usually earth,
used for the purpose of raising or changing the surface contour of an area, or
for constructing an embankment.
Fishing space. Space between head and base
of a rail occupied by a splice bar (angle bar, joint bar).
Flange. 1. A projecting edge, rib or rim on
any object such as the base of a rail on the top and bottom horizontal parts of
a beam or girder. 2. On a car wheel, the inside rim which projects below the
Flange frog. See Frog, self-guarded.
Flanger. A form of plow for clearing ice
and snow from the inside of rails to provide a clear passage for wheel flanges.
Sometimes placed under a special car called a flanger car, but usually carried
under a snowplow. Also frequently attached to locomotives, either on or just
behind the pony trucks.
Flangeway. Space between running rail and
guard rail or timber in road crossing to provide clearance for passage of wheel
Flare opening. Horizontal distance between
the gage line of running rail and the side of the head of a guard rail or frog
wing rail at the widest part of its flared end.
Flow of metal (rail). Rolling out of steel
on the crown of a rail toward sides of the head. More common on the low side of
a curve located where less than established speed is used frequently.
Forms. (Form Work, Lagging, Shuttering).
The wooden or metal construction, providing means for receiving, molding and
sustaining in position the plastic mass of concrete placed therein to the
certain dimensions, outlines and details of surfaces planned for its integral
F.R.A. Federal Railroad Administration. A
government agency under the U.S. Department of Transportation.
Fracture, detail. A progressive transverse
fracture originating in the head of a rail.
Frog. A device used where two running rails
intersect, providing flangeways to permit wheels and wheel flanges on either
rail to cross the other.
Frog angle. Angle formed by intersecting
gage lines of the rails, or by tangents to the gage lines at their point of
intersection when the frog is curved.
Frog number. One-half the cotangent of
one-half the frog angle, or the number of units of centerline length in which
the spread is one unit. The rate of spread of the gage lines at the frog. The
number of units of length for a spread of one unit.
Frog, point of. The actual point of frog,
also called the 1/2 inch point of frog, is the point at which the spread between
gage lines is one-half inch, which is the standard width of all manufactured
frog points except solid manganese steel frogs. In the latter, the metal point
is five-eighths inch wide, but the 1/2 inch is marked on the casting. All
measurements are made from the 1/2 inch point of frog. The theoretical point of
frog, the point of intersection of the gage lines, is at a distance ahead of the
1/2 inch point which in inches is equal to one-half the frog number. This
dimension is needed in turnout layouts.
Frog rigid bolted. A frog built entirely of
rolled rails, with fillers between rails, and rigidly held together with bolts.
Frog, self-guarded (flanged frog).
with a guard member for guiding the flange of a wheel past the point of frog by
engaging the tread rim of the wheel in a horizontal plane above the top of the
running surface of the frog. This makes a guard rail unnecessary.
Frog, spring. A frog constructed so that
one wing rail will spring open when activated by force of the wheel flange
passing through it.
Frog, throat of. Point at which the
converging wings of a frog are closest together.
Frozen joint. A joint so tight that the
rails cannot move as temperature varies.
Fusee. A pyrotechnic signaling
device carried by train crews and track workers. When ignited it burns with a
red light for a short period of time. A fusee may be dropped from the rear of a
train to warn following trains of danger and it is used in many other ways,
including emergency use by track workers to indicate to an approaching train a
dangerous condition of track or structure. It is used either in daylight or
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Gage Line. A line
five-eighths inch below the running surface of a rail on the side of the head
nearest the track center; the line from which measurements of gage are made.
Gage, narrow. A gage
narrower than standard gage. A gage of 24 inches or less is commonly employed
for industrial railways. Meter gage is often used in foreign countries.
Gage of track. Distance
between gage lines of rails laid in track.
Gage rod. A device for
holding track to correct gage, generally consisting of 11/4 inch rod with a
forged jaw on one end and a malleable jaw on the other end, adjustable through a
locknut. Sometimes consists of a rod made in two parts with a solid jaw on each,
united by a turnbuckle. Also called a tie rod.
Gage tool. A tool by which
the gage of track is determined. It is made of wood and steel, or all steel and
sometimes has a guard rail gage attached. It may be combined with a track level.
Gaging (of track).
Bringing two opposite rails into their correct relative positions as regards to
their distance apart.
Grade. Rate of rise or
fall of the grade line, expressed as a percentage of length; feet of rise or
fall per 100 feet of length. Also, gradient. A steady rise or fall of one foot
per 100 feet is a 1% grade.
Grade crossing. See
Grade line (grade). 1. The
line of a profile representing top-of-rail elevations of track. 2 A series of
staked elevations transferring this line to the ground or roadbed.
Grade separation. A term
applied to the use of a bridge structure and its approaches to divide or
separate the crossing movement of vehicular, pedestrian or other traffic, by
confining portions thereof to different elevations.
Grade rail. The rail first
surfaced to track elevation; the line rail on tangents, the inner or low rail on
Guard rail. 1. A rail laid
parallel to and inside a running rail to prevent wheels from being derailed or
to hold wheels in proper alignment and keep wheels on the other rail from
striking the points of switches or frogs in turnouts or crossings. 2. An
additional pair of rails laid parallel to and between the running rails of
bridges, bridge approaches, and at other critical locations, to keep derailed
wheels on the ties and near the running rails.
Guard rail clamp. A device
consisting of a yoke and fastening devices engaging the running rail and guard
rail. Not all guard rails have clamps.
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Head block (switch). A pair of ties (or, in
old types of turnouts, a single tie) used to support the switch-point operating
mechanism and the switch stand.
Head rod. The switch rod nearest the point
of a switch, usually placed between the two head block ties.
Heater, switch. A device for melting snow
at switches by means of steam, an electric current, gas jets, or oil.
Heel block (switch). A block which spans
joints and fills the space between adjacent rails at the heel of a switch,
joined with outside splice bars by continuous bolts to form a unit joint. Also
serves as a foot guard.
Heel length. Disering freight at the house.
Distance between the heel end and half-inch point of a frog, measured along gage
Heel of frog. The end of a frog
farthest from the switch.
Heel of switch. The end of a
switch rail farthest from the point of switch.
Heel spread (frog). Distance
between gage lines at the heel end of a frog.
Heel spread (switch). The
distance between the gage lines at the heel of the switch rails.
Highway-crossing protection. An
arrangement of one or more highway-crossing signals, with or without
gates, to protect highway traffic.
House track. Tracks serving
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Insulating rail joint. Sometimes called
Insulated Joint. A rail joint designed to stop the flow of electric current from
rail to rail, as at the end of a track circuit, by means of nonconductors so
placed as to separate rail ends and other metal parts.
Insulated switch. A switch in which the
fixtures, principally the gage plates and the switch rods connecting one rail to
the other, are provided with insulation so that electric currents will not be
shunted. Also, the turnout rail contains an insulating joint.
Impedance bond. An electrical apparatus at
code change points in electric traction areas to separate signal and traction
Interchange track. A track used for the
transfer of cars from one railroad to another.
Interlocking. An arrangement
of signals, switch lock, and signal appliances so interconnected that their
movements succeed each other in a predetermined order. It may be operated
manually or automatically.
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Jack, track. A compound ratchet-lever jack
which trips its load by a single operation, as distinguished from an automatic
lowering jack which lets the load drop by successive stages. There are two
kinds: single-acting, in which the load is raised on the down stroke of the
lever; and double-acting, in which the load is raised on both up and down
strokes. Track jacks now usually have 15 ton capacity.
Joint. The junction of two rails or of like
materials in bridge members.
Joint bar. A steel angle bar or other shape
used to fasten together the ends of rails in a track. They are used in pairs,
and are designed to fit the space between head and flange (fishing space)
closely. They are held in place by track bolts. Also, called angle bar, rail
joint bar, and splice bar.
Joint-bar drilling. Provision of suitable
holes at the ends of rail, switch, frog, or other track member to receive
joint-bar bolts. In specifying joint-bar drilling, give the distance from rail
end to center of the first hole, successive distance between centers of holes,
vertical locations of holes, and their diameter.
Joint, compromise. A special rail joint,
sometimes also called a step joint, for uniting rails of different sections;
made so it brings gage sides and joined rail heads into line so that continuous
smooth surfaces are presented to treads and flanges of passing wheels.
Joints, supported and
supported rail joint has a tie directly under the rail joint. A suspended joint
is one in which ends of the rail joint are carried by two consecutive ties.
Joint tie. A cross tie used
under a rail joint.
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Keeper, switch-stand. See
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- L -
Latch, switch-stand. A device for catching
and holding the lever of a switch stand in position; also called a switch
keeper. Two latches are used at each switch stand.
Lead, actual. The length between the actual
point of switch and the half-inch point of frog, measured on the line of the
Lead, curved. The degree of curvature in a
turnout between the heel of the switch and the toe of the frog, measured on the
centerline of the turnout track.
Lead track. An extended track connecting
either end of a yard with the main track.
Lens, switch lamp. A lens set in a switch
lamp. A wide-angle lens, which spreads a light of low intensity over a wide
area, is most commonly used with yard switches.
Level. The condition of a track in which
the elevation of the rails is transversely equal. Also a tool used to determine
that condition in surfacing track.
Line. The condition of track in regard to
uniformity in direction over short distances on tangents, or uniformity in
variation in direction over short distances on curves.
Line rail. The rail on which alignment is
based; the east rail of tangent track running north and south, the north rail of
tangent track running east and west, the outer rail on curves, or the outside
rails in multiple track territory.
Lining track. Shifting the track laterally
to conform to established alignment. Maintenance lining is ordinarily done
during repairs; general lining is done to make the track conform throughout to
Lipped joint. The junction of two rails
when the gage sides are not in alignment.
Live load. A dynamic load such as traffic
load that is supplied to a structure suddenly or that is accompanied by
vibration, oscillation or other physical condition affecting its intensity.
Lock washer. A spring washer.
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Mainline. Route miles of track systems
carrying main tracks.
Main track (M.T.). A track extending
through yards and between stations upon which trains are operated by timetable
or train order or both, or the use of which is governed by block signals.
Marker, snow flanger. Post or sign
indicating the proximity of an obstruction which makes it necessary to raise
snow flangers or close snowplow wings.
Mate. A structure somewhat similar to a
frog point, placed opposite a tongue switch to guide wheels and carry them
throughout the extent of the switch. It is frequently used in industrial tracks
laid in paved streets.
Middle ordinate. The distance measured from
gage line of rail on a curve to the middle of a string drawn taut and held to
contact with gage line of rail at its ends. The middle ordinate forms a
convenient means of measuring detailed curvature and is used in the adjustment
of curves and the investigation of accidents. It is also a factor in bending
rails to a desired curvature.
Movable bridge. A bridge of any type having
one or more spans capable of being raised, turned, lifted, or slid from its
normal vehicular and/or pedestrian service location to provide for the passage
of navigation. The movements of the superstructure may he produced either
manually or by engine power
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Nail, dating. A galvanized or copper nail
with a large head in which the last two numerals of the year are stamped; used
when a tie is laid or treated to indicate its service life.
Number, turnout. The number corresponding
to the number of frog used in a turnout.
Nutlock. A spring washer.
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Pantograph. A device located on top of
electric engines which collects power from the overhead contact wire by means of
a sliding contact shoe.
Parent track. A track from which a turnout
is constructed. A main track is the parent track in regard to a passing track or
spur, a ladder track is the parent track in regard to the yard tracks.
Passing track. A track auxiliary to the
main track used for meeting or passing trains.
Phase break. A location where overhead
wires are arranged to provide an insulated section between different sources of
Pile. A member usually driven or jetted
into the ground and deriving its support from the underlying strata, and by the
friction of the ground on its surface. The usual functions of a pile are: (a) to
carry a superimposed load; (b) to compact the surrounding ground; (c) to form a
wall to exclude water and soft material, or to resist the lateral pressure of
Platform, high. A passenger station
platform at approximate car-floor height.
Platform, low. A passenger station platform
at approximate top-of-rail height.
Point of switch, theoretical. The point
where the gage line of the switch rail, if produced would intersect the gage
line of the stock rail. Also called vertex.
Point rails. Switch rails.
Post, bumping. A device at the end of a
stub track to prevent rolling stock from going off the ends of the rails.
Pressure grouting. A method of pumping
concrete into unstable soil to restore support.
Profile. A longitudinal section through a
track that shows elevation and depression. Also, a drawing showing grade line of
a railroad, usually obtained from levels taken on top of the rail.
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Rail. A rolled steel shape designed to be
laid end-to-end in two parallel lines on ties, to form a track for railroad
rolling stock, traveling cranes, and the like.
Rail anchor. A device attached to a rail to
keep it from moving longitudinally as a result of temperature change or under
traffic. Also called anticreeper.
Rail bender. A tool or shop machine for
bending rails to fit curves in tracks, turnouts, or turntable circles; to
introduce bend in stock rails; and for a variety of allied operations. Two
common types are the Samson and the Jim Crow, the latter sometimes modified by
addition of a roller for continuous bending of rails.
Rail bond. A device used to transfer an
electric circuit at a rail joint.
Rail brace. A metal casting made to fit
against the side of a rail or guard rail and to be spiked to the tie on the
outside of a track or the inside of a guard rail to prevent the rail from
inclining backward with the thrust of wheels. Made in plain and adjustable
Rail brand. An identification mark,
including manufacturer's name or initials, month and year the rail was rolled,
weight per lineal yard, initials of section, number of the heat, portion of the
ingot, and process of manufacture.
Rail creeping. Intermittent longitudinal
sliding movement of rails in track under traffic or because of temperature
changes. The effect of rail creeping is resisted by anticreepers or rail
Rail fastenings. See Fastenings, track.
Rail, high. The outer or elevated rail of a
Rail joint bar. See Joint bar.
Rail joint base plate. A special tie plate
used under some types of rail joints.
Rail joint expander. A rail puller/expander
operated by hand or by machine which increases or decreases the gap between
adjoining rail ends.
Rail joint, insulated. A rail joint which
arrests the flow of electric current from rail to rail, as at the end of a track
circuit, by means of nonconductors separating rail ends and other metal parts.
Rail joint, pumping. A rail joint usually
poorly supported so that mud is created by passage of wheels and pumped up
Rail layer. A small crane, manually or
power operated, to set new rail in place with the use of few men.
Rail, lead. See Closure rail.
Rail, low. The inner rail of a curve which
is maintained at grade while the opposite or outer rail is elevated.
Rail, relayer. Rail with some wear suitable
for reuse in track. Relayer rail is divided into main track relayer rails, and
yard and side-track relayer rails. It may be cropped then welded or used as
shorter length rail.
Rail rest. A support for one or more
emergency-repair rails consisting of two or more shelved upright posts or slabs
of timber, iron or concrete.
Rail saw, portable. A tool or machine for
sawing steel rails, commonly a hacksaw or a circular steel saw, set in a
Rail section. The pattern or dimensional
details of rail, such as width of base, height of rail, thickness of web, width
and thickness of head, angle of head, and angle of base. Each particular pattern
is identified by a brand name or symbol such as ASCE, AREA, ARA, PRR and others
in addition to its weight per yard.
Rail, ribbon. Continuous welded rail free
of joints or with very few joints in long stretches.
Reamer. A steel tool designed to true or
enlarge holes in wood or steel, to facilitate passage of bolts or rivets.
Reflector. A lens device attached to switch
stand, showing different colors to indicate position of switch. The colors arise
from light reflected from the locomotive headlight.
Relay. An electrical device which contains
motors or magnets which, when excited, cause circuits to open and/or close.
This, in turn, allows switches to be thrown or signals to display desired
Relayer rail. See "Rail, relayer."
Retaining wall. A wall for sustaining the
pressure of earth or filling deposited behind it, used at railroad fills or
cuts. See also Wing Wall or Abutment.
Right of Way. Land or water rights used for
the railroad roadbed and its structures.
Riprap. Brickbats, stones, blocks or
concrete or other protective covering material of like nature deposited upon
river and stream beds and banks, lake tidal or other shores to prevent erosion
and scour by water flow, wave or other movement.
Roadbed. The finished surface of roadway
upon which track and ballast rest.
Roadbed shoulder. The portion of subgrade
lying between the ballast-covered portion and the ditch in cuts, and the top of
slope on embankments.
Roadway. The part of a railway prepared to
receive track. During construction the roadway is often referred to as the
Rod, operating. A rod attached to a switch,
derail, or other device, for moving it from one position to another.
Rotary snowplow. A car with a bladed wheel
on the front end set at right angles to track and driven by an engine on the
car. It cuts the snow and discharges it to one side of track.
Running rail. The rail or surface on which
the wheel bears, as distinguished from a wing rail or guard rail.
Runoff (suface). The grade through which
the raised portion of a track is connected with the old grade. It generally
includes the two rails and is made at a long easy slope for comfort and safety.
Runoff (curve). The profile through which
the super elevation of a curve is brought to the level of the tangent, or
through which different elevations on a compound curve are connected.
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Scale, track. A scale with a weighbridge
supporting a section of running track, used to find weight of rolling stock.
Scrap rail. Rails of standard section not
fit for use as relayer rail.
Screw spike. A cylindrical threaded steel
spike with a special head, designed to be turned with a special wrench into
holes bored in ties, to secure rails or to act as a tie plate holder in tie
plates with holes intended for this use.
Section tool house. A small building used
for storing the section motor car or hand car, maintenance-of-way tools, and
other equipment of a section gang.
Separator, adjustable. A metal block of two
or more parts, acting as a filler between running rail and guard rail and
providing a means of maintaining the proper width of flangeway.
Shake (timber). A lengthwise separation of
wood, following annular rings.
Sheave. A wheel having a groove or grooves
in its face surface for the passage of cable. This term may be applied
collectively to include both sheave and its housing block.
Shim, track. A bearing piece, usually wood
or metal of various thickness, at least equal to the width and length of the tie
plate, for temporary use between the tie plate and ties to raise (surface) the
rail to a desired relative elevation. Usually, used to spot surface a track when
the roadbed is frozen and the ties cannot be surfaced tamped; or for temporary
use to bring the tops of adjoining rails of different height to a desired plane
Shoulder, ballast. See Ballast, shoulder.
Side planning. Cuts made on sides of the
head of the switch rail to form a taper from the full width of head to the
Signal, highway, electric. A highway
crossing signal which is actuated automatically by the approach of a train and
which then displays one or any combination of several features such as red
lights (flashing or nonflashing) horizontally swinging disk, crossing gates, or
warning bell, all designed to warn motorists of the approach of a train.
Side track (S.T.). A track used
to temporarily store cars.
Siding. A track auxiliary to a main or secondary track for the
meeting or passing of trains.
Signaling, automatic block. A
system of signals of fixed location, each located at the entrance to
a block, to govern trains and engines entering and using that block.
Such signals govern movements over a series of consecutive blocks
and are actuated by a train or engine or by other conditions
affecting the use of the block, such as a broken rail, switch not
properly lined, car standing on a turnout foul of a main track or
other track obstruction.
Skeletonized track. Track with
ballast removed from the cribs between ties.
Slide fence. A warning device
connected to signals which warn trains of rock or landslides when
fence wire is broken by rock fall.
Snow fence. A structure erected
to form artificial eddies on the windward side of a cut far enough
to cause snow to deposit between fence and cut. A portable or
permanent wood fence, a hedge, or stone fence is usually employed.
Snow melter. A contrivance
designed to prevent accumulation of snow and ice in tracks;
sometimes a blowtorch held close to the snow, or a steam, electric,
oil, or gas heater attached to the rails through the switch leads at
interlockings or railroad crossings; sometimes chemical poured or
strewn along the tracks.
Snowshed. A roofed structure
built over tracks to protect traffic against snow blockades.
Restricted to locations where snow encroaches seriously and cannot
be handled with plows, usually in side-hill cuts on mountain slopes
where snowslides amounting to avalanches frequently bury the tracks.
Spike puller. A steel bar about
5 feet long with a claw end shaped for pulling spikes by leverage;
also called a claw bar.
Spike puller extension. A tool
with a claw end and two or three pairs of knobs on a straight bar. A
spike puller is engaged with the knobs after the claw is slipped
under the spike head. It is used to withdraw spikes from flangeways
and other places in which a spike puller alone cannot operate.
Spiked switch. A switch with
its points held in fixed position by a spike, usually to prevent a
disconnected or damaged switch from being thrown through error, or
to prevent trains from using a track that has been taken out of
Spiral easement. See Curve,
Splice bar. A joint bar.
Split switch. A device
consisting of two tapered rails with necessary connections, designed
to divert rolling stock from one f reinforced concrete
structures.Spotboard. A sighting board placed above and across a
track at an established height above top of rail elevation, to
indicate a new surface and insure uniformity of surface.
Spring frog. See Frog, spring.
Spring washer. A washer
designed to prevent a nut from loosening under vibration. Spring
washers are of two types: helical and elliptical. Also called lock
washer and nutlock.
Stock guard. A rail-high panel
of material difficult for hoofed animals to traverse, used to
continue a stock fence across a railroad.
Stock rail. A running rail
against which a switch point operates.
Stock rail bend. The bend or
set which must be given the stock rail at the vertex of a switch to
allow it to follow the gage line on the turnout. Usually, only one
stock rail of a switch is bent. The opposite one is straight.
Stop, car. A device for
stopping a car by engaging the wheels, as distinguished from a
bumper, which engages the coupler of a car or the front bumper beam
of a locomotive.
Strain. The distortion of a
body produced by the application of one or more external forces and
measured in units of length. In common usage, this is the
proportional relation of the amount of distortion divided by the
Stress. The resistance of a
body to distortion when in a solid or plastic state and when acting
in an unconfined condition. Stress is produced by the strain
(distortion) and holds in equilibrium the external forces causing
the distortion. It is measured in pounds or tons. Within the elastic
limit the strain in a member of a structure is proportional to the
stress in that member.
Stringlining. A method for
determining the corrections to be made in the alignment of a curve,
by measuring ordinates to the outer rail and without the use of
Subgrade. Gravel, crushed rock
or the like, usually inferior to the ballast used in the track,
spread on the surface of the cut or fill prior to distributing ties
and ballast. That portion of ballast over 18" inches below
bottom of ties is usually classified as subballast, commonly known
as subgrade material.
Subballast. Any material of
superior character, which can be spread on the finished subgrade of
the roadbed, to provide better drainage, prevent upheaval by frost
and better distribute the load over the roadbed.
Substation. A location where
power is received at high voltage and changed to required voltages
and characteristics for distribution to the catenary system, third
rail, and other electric apparatus. It may contain transformers,
rotating machinery, circuit breakers, sectionalizing switches,
Superelevation. The height the
outer rail is raised above the inner or grade rail, on curves, to
resist the centrifugal force of moving trains. This should not be
confused with cross level, on tangent (straight) track.
Surface (of track). The
condition of a track as to vertical evenness or smoothness over
Surface, running (tread). The
top surface of the railhead on which the wheel tread rides or runs.
Surfacing, out-of-face. Raising
the entire track to a new grade.
Switch. A pair of movable track
rails, with their fastenings and operating rods, providing a
connection over which to move rolling stock from one track to
another. Also called split switch.
Switch fixtures. The connecting
and bearing parts for the rails of a split switch.
Switch guard. A structure,
usually of manganese steel, secured outside the running rail at the
point of switch, with suitable flares to engage with the tread rim
of wheels and guide them past the switch point without blow or undue
Switch heater. A device for
melting snow with heat generated by an electric current, or by gas
or oil; used for movable parts of switches, etc.
Switch lock. A fastener,
usually a spring padlock, used to secure the switch or derail stand
in place and thus maintain correct position of these members.
Switch plate. A special metal
tie plate for use on switch ties, each plate being long enough to
extend not only under the stock rail and its supporting braces, but
also under the switch rail in open position. Switch plates are
furnished in sets to correspond with switch length. There are two
plates to each tie; however, at point of switch, the two may be
replaced by a gage plate which carries both switch rails.
Switch, actual point of. See
Point of Switch.
Switch, theoretical point of.
See Point of Switch.
Switch-point lug. The lug
attached to a switch point, to which the front rod is connected.
Switch rail (point rail). The
tapered rail of a split switch.
Switch rod, adjustable. A
switch rod with an attachment for altering its length to keep the
switch rails in their proper positions. Adjustment is usually
effected through staggering holes in the clips which connect switch
rod and switch rail.
switch in which one point is placed in advance of the other, as in a
turnout from inside a curve.
Switch stand. A device by which
a switch is thrown, locked, and its position indicated. It consists
essentially of a base, spindle, lever, and connecting rod, together
with target, and can be equipped with a lamp or banner. Unless
described as "low" or "center throw", its target
spindle extends 2 feet or more above top-of-rail elevation.
Switch stand, center throw.
switch stand with a spindle higher than 1 foot but less than 2 feet.
This type is commonly used in yards, less frequently on main track
because targets are not as readily visible to engineman as are high
Switch target. A visual day
signal fixed on the spindle of a switch stand, or the circular
flaring collar fitted around the switch-lamp lens, and painted a
distinctive color to indicate the position of the switch.
Switch, throw of. The distance,
measured along the center line of the rod nearest the point
connecting the two switch rails, through which switch points are
moved sidewise to bring either point against the stock rail;
standardized at 43/4 inches.
- T -
Tamper, air. An air-driven tool for
compacting ballast under ties. Commonly used in sets of 4, 8, or 12 tools in
connection with a portable air compressor.
Tamper, electric. An electrically driven
tool used for compacting ballast under ties. Commonly used in sets of 4, 8, or
12 tools in connection with a portable generator set. (Electric tampers are of
three general classes: vibratory, magnetic impulse, and mechanical impulse.)
Tamper, mechanical. A power-driven machine
for compacting ballast under ties.
Team track. A track on which freight is
transferred directly between railroad cars and highway vehicles.
Thimble. The cylindrical pieces of an
insulating joint which surround portions of the bolts.
Third rail. An electric conductor located
alongside the running rail from which power is collected by means of a sliding
contact shoe attached to the truck of electric equipment.
Throat of frog. The point at which the
converging wings of a frog are closest together just ahead of frog point.
Throw of switch. See Switch, throw of.
Throw rod. The rod attached to the head rod
of a switch, connecting the switch to a switch stand or other operating device.
Tension. An axial force or stress caused by
equal and opposite forces pulling at the ends of the members. In simple bending
it is also present above or below the neutral axis.
Tie. A transverse support to which rails
are fastened to keep them in line, gage and grade. Usually wooden or concrete.
Tie plate. A metal plate at least 6 inches
wide and long enough to provide a safe bearing area on the tie, with a shoulder
to restrain outward movement of the rail.
Tie, plate, canted. A tie plate tapered in
thickness usually on a slope of 1 in 20, for the purpose of inclining the rail
toward the center of track for easier maintenance of gage, more uniform wear of
head, and central loading of rail.
Tie plate, twin. A tie plate in two parts
which mate to form a combined width equal to that of the stand tie plate, for
use back of the heel of switch to the point where standard tie plates may be
applied without their ends infringing.
Tie plug. A wooden pin driven in to fill an
unused spike hole in a tie, to exclude moisture, prevent decay, and provide
solid wood for redriving the spike. Usually supplied in the form of sticks
containing several plugs; frequently of treated wood.
Tie rod. See Gage rod.
Tie spacing. The distances between tie
centers in track or turnout.
Tie tamper. See Ballast tamper.
Tie tongs. A tool designed to engage a tie
with a lever grip; with handles by which ties can be carried or drawn into or
out of the track renewals.
Toe end of frog. The end of a frog nearest
Toe spread. The distance between gage lines
at the toe end of the frog.
Tolerance. An allowance made for a small
variation from dimensions specified.
Track, body. Each of the parallel tracks of
a yard, on which cars are switched or stored.
Track. The rail, ties, rail fastenings,
hardware and roadbed between points four feet outside of each rail.
Track brace. An auxiliary fastening
designed to function as a rail brace and a gage rod.
Track fastenings. The term commonly applied
to rail joints, bolts and spikes.
Track fastenings, auxiliary. The term
commonly applied to spring washers, tie plates, rail braces, anticreepers and
Track, house. A track alongside of or
entering a freight house; used for cars receiving or delivr operated by
electric, gasoline or air power.
Track, ladder. A track connecting successively the body tracks of a yard.
Track-laying machine. A machine designed to
minimize the manual labor of placing rails, fastenings, ties and other
Track level. A board with a spirit level
attached, to level the rails of a track usually equipped with a series of steps
to set superelevation on the outside rail of curves.
Track liner. A device designed to minimize
manual labor in lining track. It consists generally of a base resting securely
on the roadbed to act as a fulcrum for some form of lever arm.
Track, repair or rip. One of the body
tracks in a car repair yard or shed, on which repairs are made to rolling stock.
Track shim. A hardwood or fiber plate,
generally as wide as the bearing of a standard tie plate but of a varying
thickness; used to restore the running surface of track heaved by frost or
Track, storage. One of the body tracks in a
storage yard, or a track used for storage purposes.
Track, spur. A track connected with the
parent track at one end only.
Trailing point. A switch in which points
face away from the normal direction of traffic. A trailing point move would pass
over the frog and then the switch points.
Transformer. Apparatus which serves to
increase or decrease voltage.
Transpose rail. Changing rail from one side
to the other on curves because of headwear from tangent to full curvature or
Transition spiral. An easement curve.
Trestle. A bridge structure consisting of
beam, girder or truss spans supported upon bents. The bents may be of the piled
or of the frame type. When of framed timbers, metal or reinforced concrete they
may involve two or more tiers in their construction. Trestle structures are
designated as "wooden", "frame", or "framed",
"metal", "concrete", "wooden pile", "concrete
pile", etc., depending upon or corresponding to the material and
characteristics of their principal members.
Train. A locomotive with or without cars
and displaying markers.
Truss. A jointed structure having an open
built web construction so arranged that the frame is divided into a series of
triangular figures with its component straight members primarily stressed
axially only. The triangle is the truss element and each type of truss used in
bridge construction is an assemblage of triangles. The connecting pins are
assumed to be frictionless.
Turnout (T.O.). An arrangement of a switch
and a frog with closure rails, by which rolling stock can be diverted from one
track to another.
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- W -
Wide Flange Beam (Carnegie Beam). A steel
rolled member having an H-shape with its flanges wider and its web thinner than
Wing Wall. An extension wall of an abutment
wall which retains adjacent earth and/or deflects or guides a stream into pipes,
culverts, and the waterway of a bridge.
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- Y -
Yard Track (Y.T.). A track within a yard
used to receive cars for classification for rerouting.
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