A.A.R. INTERCHANGE RULE 91: Statement of maximum allowable gross weights for both four axle and six axle railroad cars, based on axle journal size ( diameter x length, in inches ), as prescribed by the Association of American Railroads, Mechanical Division.
A.A.R. OPEN TOP LOADING RULES: Standard procedures and specifications for loading and securing various types of loads to railroad freight cars, including excess dimension loads in both single or multiple car situation, as stated in General Rules Governing the Loading of Commodities On Open Top Cars, published by the Association of American Railroads, Mechanical Division.
" A " DIMENSION:
- In a bolstered load, the distance from the center of the fixed ( non-sliding ) bolster to the longitudinal center of the slot of the sliding bolster ( nominal position of pin of sliding bolster when consist of bolster cars and center idler car(s) are on tangent track).
- In a schnabel car load, the distance between the two halves of the car, horizontal pin to horizontal pin, not necessarily maximum length of suspended load.
- See Midordinate Offset.
" A " END OF CAR: The opposite end to that on which the brake wheel is located. In the event there are two brake wheels, the ends are designated by stenciling the letters "A" and "B", respectively, on both sides, near the ends.
ABOVE TOP OF RAIL ( ATR ): Distance from Top of Rail Line measured perpendicular to Top of Rail Line and parallel to Track Centerline ( as viewed in an upright plane ).
AXLE LOADING: Total weight on each axle expressed in Pounds per Axle ( or Thousands of Pounds, or "Kips", K per Axle). When load is not longitudinally centered on car, the axles of the truck closest to longitudinal center of gravity of load will carrying a greater total load than the axles of the truck farthest from the center of gravity of the load and their loading is Maximum Axle Loading, and is of more significance in most cases than Average Axle Loading.
AXLE SPACING: Distance between centers of adjacent axles of a single truck measured parallel to longitudinal centerline of car.
"B" DIMENSION: See Endswing Offset.
"B" END OF CAR: The end on which the brake wheel is located. In the event there are two brake wheels, the ends are designated by stenciling the letters "A" and "B", respectively, on both sides, near the ends.
BALLAST: Supplementary material of prescribed weight, not part of load proper but considered as dunnage, that is used to keep position of combined center of gravity within reasonable limits. Also referred to as Counter Balance.
BASE CAR: Car having defined specifications or characteristics so as to facilitate comparison to another type of car or define a basis for:
- Published Line Clearance Envelopes.
- Moment and Shear Tables used in figuring maximum permissible loading of bridge spans.
- Maximum Track Curvature Negotiability of a certain car or locomotive when coupled to a given base car or locomotive.
BASE END: Bottom end of cylindrical vessel designed to be installed in vertical position.
BASE RING: Concentric circular protruding reinforcement structure at bottom end of cylindrical vessel designed to be install in vertical position.
BOLSTER: One of two pivots that support an extremely long load mounted on two flat cars called Bolster Cars. One bolster, the Fixed Bolster, can only rotate horizontally on its car, and the other bolster, the Sliding Bolster, can rotate horizontally and also slide longitudinally in a slot on its car as the entire consist of cars and load goes into or out of a curve. Sliding bolster also accommodates slack action of cars.
BOLSTER LOAD: A load, usually extremely long, support at two points by a pivoting bolster at each point. The bolsters are located on separate cars.
BOLSTER SPACING: Distance between bolster centers measured along longitudinal centerline of load.
BUFFER CAR: Usually a nonload-supporting or idler car ( almost always a flat car ) that is located on outside of bolster car consist. Never used to describe an idler car located between bolster cars. See Idler Car.
CAPACITY ( CAPY ): The nominal working load of a freight car expressed in pounds, gallons, or cubic feet which the car is designed to carry. This figure is stenciled on the car.
CAR FLOOR HEIGHT ( CFH ): The height Above Top of Rail of the car floor ( surface upon which the load and/or dunnage are placed ).
"C" DIMENSION: Truck centers of a bolster car, used as input data in equation or table for figuring " T " Value, inside offset of bolster Center from Track Centerline.
CENTER OF GRAVITY ( CG ): Center of mass of an object. The point from which the component of gravity pulls downward.
CIRCUITOUS ROUTE: Railroad routing for excess dimension load movement that is not on the most direct railroad route because extreme dimension(s) of load would cause fouling of fixed obstruction(s) located on most direct route. A Circuitous Route may also be necessary because of excess weight for the most direct route.
CLEARANCE DIAGRAM: A graphic depiction for visually comparing load configurations with fixed obstruction configurations, or with car or load configurations on an adjacent track. A clearance diagram is oriented in an upright plane perpendicular ( radial in a curve ) to the centerline of a specified track and faces a stated timetable direction and is drawn in a stated scale. The Top of Rail Line and the Track Centerline are the two fundamental axes of a Clearance Diagram. Any track curvature adjacent to an obstruction should be explicitly stated ( including direction, left or right ) so that the resulting offsets can be figured for both the inside and the outside of the curve, in order to obtain estimated clearances for a specified load configuration.
COMBINED CENTER OF GRAVITY ( CCG ): Center of Gravity of Car, Dunnage, and Load combined as one rigid unit.
(CG Car)(WT Car) + (CG Dunnage)(WT Dunnage) + (CG Load)(WT Load)
CCG = -------------------------------------------------------------------
WT Car + WT Dunnage + WT Load
CCG is expressed in inches Above Top of Rail. In many routine review of excess dimension and excess weight loads, the middle term both above and below the line can be omitted and the weight of the dunnage combined into the weight of the load, in order to obtain a reasonably close estimate.
COMPOSITE DIMENSIONS:
- The overlay of all of the most restrictive obstructions on a given route segment to create a table or plot showing minimum side distances at all heights Above Top of Rail. A statement should be made if the Composite pertains to only those obstructions adjacent to tangent track or the maximum track curvature adjacent to obstructions on the route.
- The widest and highest dimensions of a group of several loads.
CONCENTRATED LOAD LIMIT: Maximum permissible weight of lading that can be placed on a limited portion of the deck of a car body. the value of this maximum permissible weight limit increases as the lading is distributed over a greater length of deck, reaching the Load Limit for the car at a specified length of lading for each designated series of cars.
CONSIGNEE: Person, company, or entity receiving a shipment.
CONSIGNOR: Person, company, or entity sending a shipment. Also referred to as shipper.
COOPER E LOADING: A live loading concept originally designed by Theodore Cooper in 1894 for the design of railroad bridges. The " E " originally stood for steam engine, and designated the axle load on the drivers ( drive wheels ).
COOPER E RATING: (1) For Cars: A measure of the effects of a load ( car ) or a series of loads ( cars ) on a railroad bridge span expressed in terms of the design Cooper E Loading. (2) For Bridges: A measure of the load carrying capacity of a railroad bridge span expressed in terms of the design Cooper E Loading.
COUNTER BALANCE: See Ballast.
COUPLED LENGTH: Nominal length of a car measured between pulling faces of couplers. Maximum specified length of a car that is necessary in order to figure consist of bolster cars and idler cars. also referred to as Outside Length, Over-All Length or Pulling Face Length.
CURVATURE: Sharpness of a curved track alignment expressed in degrees of direction change per 100 feed of chord distance between two points on Track Centerline.
CURVATURE SENSITIVE: Referring to a bolstered load ( or schnabel car load ) with particularly long bolster ( or pivot ) centers and/or end overhang compared to the actual width or height of the load. Such a load encounters little or no clearance problems on tangent track, but as track curvature increases the midordinate offsets on insides of curves and/or the endswing offset on outsides of curves increase at a particularly high rate, necessitating extraordinary precaution in areas of high track curvature before authorizing movement of the load.
CURVE: Track alignment having constant or variable radius ( constant or variable curvature ). Track alignment that is not tangent.
CUSHIONED UNDERFRAME: A slack control and energy absorption device to prevent shocks and impact stresses from damaging the car structure or lading being carried. Because of the large amount of longitudinal travel available, cars equipped with end of car cushioning must never be used as center idler cars between bolster cars or as bolster cars. Only cars with conventional draft gears or sliding center sills should be used as center idler cars.
CYLINDRICAL VESSEL: Load generally shaped as a cylinder, sometimes an assemblage of two or more cylinders of different diameters on a common axis.
"D" DIMENSION: Distance between Bolster Center and nearest Truck Center of a bolster car, used as input data in equation or table for figuring " T " Value, inside offset of Bolster Center from Track Centerline.
DEGREE OF CURVE: See Curvature.
DEPRESSED CENTER CAR: Usually a heavy duty flat car with load deck between both trucks at a lower level than load decks at ends of car.
DIAGONAL CLEARANCE ( DCL ): Distance between a load and an obstruction, using Effective Half-width ( including offsets resulting from any track curvature ), measuring on the shortest distance not parallel or perpendicular to Top of Rail Line in a plane of measurement perpendicular to Track Centerline and Top of Rail Plane.
DOUBLE END OVERHANG: Load that extends longitudinally beyond truck or bolster centers at both ends.
DUNNAGE: Material used to secure load to car or balance load. Dunnage is not part of car and is not part of actual load proper. Also the weight of such material.
EFFECTIVE WIDTH: Range, left to right, of actual distance of lateral extremities of car or load from Track Centerline, taking into account the midordinate and endswing offsets resulting from a specified maximum track curvature, truck or bolster centers, and end overhang. The maximum midordinate offset or endswing offset, whichever is greater, is doubled and added to the measured width of the car or load to give the value of the Effective Width. See also Equivalent Width.
END OVERHANG: Distance between truck or bolster center and longitudinal extremity of load, always measured along prolongation of line between truck or bolster centers. Truck or Bolster Center Overhang is understood unless Overhang Over Extremity of Carbody, Overhang Over Strikers, etc. is specifically stated.
END SILL: The transverse member of the underframe of car body extending across the ends of all the longitudinal sills. Used in referring to longitudinal extremity of car body.
ENDSWING OFFSET ( EO ): Displacement of car or load radial to Track Centerline and parallel to Top of Rail Line, always on outside of curve and greatest at point of maximum end overhang, that is proportionate to track curvature, truck or bolster centers, and end overhang. Also referred to as Outside Swing, Swingout, or " B " Dimension. L(2) - C(2)
EO = ------------------------- X 12
8 (R)
-
EO.....is expressed in inches per degree of track curvature.
L......is total length of load in feet from point of maximum end overhang
to point of maximum end overhang, assuming both end overhangs are equal.
C......is truck or bolster centers in feet.
R......is radius of one degree curve in feet ( 5,729.65 feet ).
In a multiple load, ordinate offset of Bolster Center from Track Centerline per degree of track curvature ( " T " Value ) is subtracted from the EO value given by above equation or table in order to obtain net EO.
-
ENVELOPE: A delineation in an upright plane that is perpendicular or radial to the Track Centerline and that defines a specific area within that plane which pertains to available space for loads, or space that is to be checked for potential obstructions.
EQUAL END OVERHANG: Load longitudinally extending beyond truck or bolster centers by the same amount at each end.
EQUIPMENT REGISTER ( The Official Railway Equipment Register ): The catalog of freight cars owned by railroads and private car companies of North America, listing the physical characteristics of each car such as length, width, height, number of axles, truck centers, and load carrying capacities.
EQUIVALENT WIDTH: When a load is not transversely symmetrical about the centerline of a car, the greater of the two half widths is doubled to obtain the Equivalent Width. See also Effective Width.
FIXED BOLSTER: See Bolster.
FLAT CAR: Freight car with no supporting structure above load deck, except for bulkheads at ends of car in some types.
FLOOR HEIGHT: See Car Floor Height.
FOREIGN CAR: Car owned by another railroad, private car leasing company, manufacturing company, or governmental agency.
GAUNTLET TRACK:
- An offset track ( or set of rails ) in which both rails are approximately one foot farther from a side obstruction than the corresponding rails of the parent track which is connected to at both ends by switch points with no turnout frog. Occasionally used opposite a high level passenger platform or similar side obstruction where parent track must be close to obstruction and an offset bypass track is necessary to accommodate some excess dimension loads.
- An offset track similar to (1) in which a second track goes through a bridge designed for one track. A turnout frog with no switch points is used outside each end of the bridge. If original track having no turnouts is used outside each end of bridge, gauntlet track will have less side clearance ( on one side ) than original track. Because centerline of gauntlet track is offset from centerline of bridge ( or when both tracks are equally off-centered ) care must be exercised when evaluating the effects of a heavily loaded car on the bridge structure when such a car is using off-centered track.
GONDOLA CAR: Open top freight car with four sides, which does not have the capacity to unload bulk materials through bottom of car.
GROSS WEIGHT: Total of weight of car, net load, and dunnage.
HEAVY DUTY CAR: Car having weight capacity in excess of 100 tons.
HORIZONTAL: Parallel to horizon on level line, perpendicular to vertical or plumb line. On clearance diagrams Top of Rail Line should not be confused with Horizontal for obstructions next to curves where there is track superelevation.
IDLER CAR: Generally a non-load carrying flat car or gondola car that is used in train consist for:
- Providing space for load end overhang that extends beyond striker of load car.
- Providing connection between two bolster cars carrying an extremely long load.
- Providing separation between loaded cars or locomotive when a load is extremely heavy.
- Providing additional braking capacity to supplement the braking capacity of a heavily loaded car.
INSIDE SWING: See Midordinate Offset.
INTERCHANGE: (1) A common point or junction of two railroads at which cars can be received or delivered. (2) The transferring of cars between railroads.
JOINT TRACK: Track that is owned, operated, or maintained by more than one operating railroad company.
JOURNAL: One of two parts of a railroad car axle ( generally at each end of the axle ) on which a bearing rests or is mounted.
KIP ( K ): Unit of 1,000 pounds of weight.
LADING: Net load or commodity being transported on a railroad freight car.
LATERAL SHIFT: (1) Displacement of load on car deck to left or right as a result of inadequate securing of load. Also referred to as Transverse Shift. (2) In a schnabel car, the capability of horizontally offsetting load and supporting arms perpendicular to Track Centerline in order to clear fixed obstructions or equipment on an adjacent track.
LEVEL: A horizontal line or surface.
LIFT: In a schnabel car, the capability of vertically raising ( perpendicular to Top of Rail Line in superelevated track ) or lowering load and supporting arms in order to clear fixed obstructions or equipment on an adjacent track.
LIGHT WEIGHT ( LT WT ): Weight of empty railroad car expressed in pounds. This figure is stenciled on the car. also referred to as Tare Weight.
LOAD CARRYING PLATFORM: Deck of car body that can be used to carry a load.
LOAD DISTRIBUTION: Spreading of total weight of load over a specified number of feet of deck of car body parallel to longitudinal axis of the car.
LOAD LIMIT ( LD LMT ): Absolute maximum allowable weight of load, including both net weight and dunnage, that a freight car is authorized to carry. This figure is stenciled on the car.
LOCAL SERVICE: Train service that makes pickups and setouts of cars at all intermediate points.
LONGITUDINAL: Parallel to length of car.
MANWAY: Structure that protrudes out from external surface of vessel, through which a workman can enter. Normally a manway has a cover plate over it.
MAXIMUMS: The largest load dimensions permitted within a given clearance envelope.
MIDORDINATE OFFSET ( MO ): Displacement of car or load radial to Track Centerline and parallel to Top of Rail Line, always on inside of curve and greatest at midpoint between truck or bolster centers, that is proportionate to track curvature and truck or bolster centers. Also referred to as inside Swing, Swingin, or " A " Dimension. C(2)
MO = ---------------------- X 12
8 (R)
-
MO....is expressed in inches per degree of track curvature.
C.....is truck or bolster centers in feet.
R.....is radius of one degree curve in feet ( 5,729.65 feet ).
In a multiple load, ordinate offset of Bolster Center from Track Centerline per degree of track curvature ( " T " Value ) is added to the MO value given by above equation or table in order to obtain net MO.
-
-
MOMENT AND SHEAR TABLE: A tabular listing of the effects of a load or series of loads over a number of bridge spans of varying lengths. For railroad use, these effects are measured in terms of the design Cooper E loading.
MULTIPLE CAR SHIPMENT: More than one load going to same destination at the same time.
MULTIPLE LOAD: Load supported by more than one car.
NOMINAL WEIGHT: See Capacity.
NOZZLE: Structure that protrudes out from external surface of vessel, used for pipeline connection.
OUTSIDE LENGTH: See Coupled Length.
OUTSIDE SWING: See Endswing Offset.
OVER-ALL LENGTH ( OAL ): (1) Length of a car over pulling faces of couplers. (2) Total length of a load.
OVERHANG ( OH ): See End Overhang. OVERHEAD CLEARANCE ( OHCL ): Distance between a load and an obstruction situated above the load, using Effective Half-width ( including offsets resulting from any track curvature ), measuring perpendicular to Track Centerline and Top of Rail Plane. Can also apply to distance between Top of Rail Line and an obstruction situated above. On superelevated track in a curve Overhead Clearance is not the same as Vertical Clearance because Top of Rail Line is not horizontal.
OVERLOADED: Condition that exists when:
- Weight of net load and dunnage exceed the Load Limit of car.
- On a single load, overloading can happen if unequal distribution of lading ( within Load Limit for total car ) results in one truck being loaded greater that fifty percent ( 50% ) of Load Limit of car.
- On a bolster car, having excess weight on one truck because of bolster being offset excessively, from midpoint between truck centers.
- Weight ( within Load Limit for total car and equally distributed between both trucks) is concentrated on too small an area of load platform of car body.
PIVOT PIN: Cylindrical portion of bolster that rotates in base of bolster. Always perpendicular to deck of bolster car. Also applied to rotating pin of schnabel car arm.
PIVOT POINT: As seen in plan view, vertical axis about which bolster pins or schnabel arm pins rotate.
PLATES: " B ", " C ", " E ", " F ": Diagrams delimiting cross-sectional area that a certain series of railroad cars can be built within, as a condition for moving in unrestricted or limited interchange service, as prescribed by the Association of American Railroads, Mechanical Division.
PROTRUSIONS: Projecting portions of a load such as nozzles, manholes, pipes, braces, clips, etc. that are attached to the outside surface of a vessel. Also referred to as Projections.
PUBLISHED LINE CLEARANCES: Information contained in the Railway Line Clearances book, such as load dimensions and weights permitted over various territories of the individual railroads without requesting advance permission for the shipment, type of car that clearances are based on, maps showing routes of some railroads, and individual to contact for each railroad.
PUBLISHED LINE CLEARANCES ( PLC ) COLUMN: See Published Line Clearances Envelope.
PUBLISHED LINE CLEARANCES ( PLC ) ENVELOPE: Delimitation of available space for loads that exceed a freight car end view configuration but do not have dimensions so excessive as to require special advance authorization for movement. This delimitation is numbered Columns corresponding to segments of railroad line. Each Column states maximum Widths in Feet and Inches at given Heights Above Top of Rail in Feet and Inches, and is published in Railway Line Clearances based on information furnished by the individual railroads.
PULLING FACE: Inside face of coupler knuckles comprising principal surface of contact between couplers of coupled cars when being pulled. Basic reference point for car length and figuring consist of cars and loading arrangement of a multiple load.
PULLING FACE LENGTH: See Coupled Length.
REDUCED PIVOT: In some models of schnabel cars the two pivot points are closer together than the two roller paths that distribute load weight from the arms to the centers of the main span bolsters. Designing a smaller distance between pivot points reduces the midordinate offset per degree of track curvature for a given length of load suspended between the arms.
RESTRICTION: Reduced Speed, Stop And Proceed on Hand Signals ( SAPOHS ), or other operating condition imposed on the movement of a specified car or combination of car and load to assure safe operation over a specific route, or safe passage by a fixed obstruction or equipment on adjacent tracks. A restriction can be based on several criteria: number of axles per car, weight of load, height of load Above Top of Rail, width of load, length of load, ratio of truck centers or bolster centers to length of load, combined center of gravity of car and load, or other conditions. See Slow Order.
RIDEOVER CLEARANCE ( ROCL ): Distance between a load and an obstruction situated below the load, using Effective Half-width ( including offsets resulting from any track curvature ), measuring perpendicular to Track Centerline and Top of Rail Plane. On superelevated track in a curve Rideover Clearance is not the same as Vertical Clearance because Top of Rail Line is not horizontal.
ROUNDS DOWN TO: Used in stating cross section configuration of cylindrical load having no protrusion. Height Above Top of Rail at car centerline and top of cylindrical load is first stated. Width usually is stated a 0 Feet 0 Inches, followed by " Rounds Down To ", which describes both sides of cylinder following a circular curve down through a 90 degree quadrant to point of maximum width ( diameter ) of cylinder. Height Above Top of Rail and Width at this height are then stated.
ROUNDS IN TO: Similar definition to " Rounds Down To ".
ROUNDS OUT TO: Similar definition to " Rounds Down To ".
ROUNDS UP TO: Similar definition to " Rounds Down To ".
SADDLE: A supporting structure shaped to conform to the load it supports. A Saddle is usually a cradling arrangement of blocking for securing a cylindrical load on a flat car deck and differs from a Bolster in that only one car supports load, and Saddle is rigidly fixed to car deck.
SCHNABEL CAR: A heavy duty, privately owned railroad freight car composed of two symmetrical halves that carry a load attached between the pivoting arms of each half of the car. The load and any accessories, such as suspension bars, become structurally a part of the entire car assemblage. In some cars, that portion including the load and arms can be hydraulically shifted horizontally or lifted vertically in order to clear fixed obstructions or equipment on an adjacent track.
SHIFT: See Lateral Shift.
SIDE CLEARANCE ( SCL ): Distance between a load and an obstruction situated left or right of the load, using Effective Half-width ( including offsets resulting from any track curvature ), measuring parallel to Top of Rail Line in a plane of measurement perpendicular to Track Centerline and Top of Rail Plane. Can also apply to distance between Track Centerline and an obstruction situated left or right. On superelevated track in a curve Side Clearance is not the same as Horizontal Clearance because Top of Rail Line is not horizontal.
SINGLE END OVERHANG: Load that extends longitudinally beyond truck or bolster centers only at one end.
SINGLE LOAD: Load supported by one car only. Load can be within end sills or overhang beyond one or both end sills, necessitating one or two idler cars, but still a single load.
SKIRT: (1) A shroud covering internal components of a vessel, usually of light gauge material and not capable of using to support the vessel. (2) Flaired appurtenance to a load, usually found encircling base end of cylindrical vessels.
SLIDING BOLSTER: See Bolster.
SLOW ORDER: Special temporary instruction issued to crews of trains and other operating personnel designating the location at which speed is to be reduced to assure the safe operation of trains and engines over section of railroad track due to track, subgrade or bridge condition. See Restriction.
SPAN BOLSTER: In a heavy duty car having more than two trucks, the structural connection between two adjacent trucks which links them into a single assemblage upon which one end of the car is supported.
SPECIAL SWITCH: Switching movement of high-wide or heavy load, usually within terminal limits, with locomotive or train used exclusively for the special load. Special switch may be employed to transfer load between yards or facilities of two railroads or to move load between shipper's plant and rail yard. See Special Train.
SPECIAL TRAIN: Train which is operated on an expedited schedule or under special service or transportation requirements specified by the consignor, consignee or the agent of either at a charge in addition to the applicable class or commodity rates or fares; or a train which is assembled in accordance with instructions given to a rail carrier by a consignor, consignee or agent of either. ( Freight Tariff WTL 9100 Series, Item #130, Effective 01-29-86 ). An example of a Special Train could be a train used for movement of one or more cars carrying excess dimension or excess weight load(s) because speed restrictions and/or numerous stops would unnecessarily impede movement of a regular freight train and cause operating problems. See Special Switch.
SPIRAL: Curve of constantly changing curvature that is used as a transition between tangent track and circular curve track of constant curvature, or as a transition between two portions of track of different constant curvature.
STENCILED LOAD LIMIT: See Load Limit.
STIFFENER RINGS: Structural members of a cylindrical vessel that wrap around the outside surface diameter ( appearing as ribs ) and keep the vessel from becoming out of round.
STOP AND PROCEED ON HAND SIGNALS (SAPOHS): Operating instructions imposed on movement of excess dimension load because of close estimated clearances at an obstruction, specifying a stop and visual inspection of load and obstruction prior to gradually going past obstruction after receiving hand signal.
STRIKER: A member placed on the ends of the center sills of freight cars against which the horn of the coupler strikes, preventing damage to the draft gear and center sills. Also referred to as Striking Plate. Car length over strikers is always greater than length over end sills ( car body ) but always less than length over pulling faces of couplers.
SUPERELEVATION: Increased height of outer rail in curved track alignment that tilts locomotives and cars toward inside of curve so as to counterbalance the centrifugal force toward the outside of curve resulting from the normal operating speeds through the curve.
SWINGIN: See Midordinate Offset.
SWINGOUT: See Endswing Offset.
TANGENT: Straight track alignment that has no specified curvature.
TARE WEIGHT: Light weight of intermodal container or railroad car. See Light Weight.
TIE DOWNS: Rods, straps, cables, chains or other dunnage used to secure commodity to railroad car. In a bolster load, the same means of securing the commodity to the bolsters instead of to the deck of the car.
TON:
- Short Ton ( Net Ton ) is a unit of measurement used in expressing weight capacity of railroad cars and intermodal containers/trailers, or weight of shipment, and is equivalent to 2,000 pounds or 2 kips ( 2K ).
- Long Ton, used for weight of shipment of some bulk commodities, is 2,240 pounds.
- Metric Ton, used for weight capacity of intermodal containers or weight of international shipments, is 1,000 kilograms or about 2,205 pounds.
TRACK CENTERS: Distance between centerlines of adjacent tracks.
TRANSVERSE: Perpendicular to length of car.
TRANSVERSE SHIFT: See Lateral Shift.
TRUCK CENTERS: Distance between pivot points of the two trucks or span bolsters on one car.
" T " VALUE: Ordinate offset of Bolster Center from Track Centerline toward inside of curve, measured perpendicular to line between truck centers of car that supports bolster. Is midordinate offset only when bolster is centered at midpoint between truck centers. ___________________
T = [ R - \/ R(2) - D ( C - D ) ] X 12
T....is expressed in inches per degree of track curvature.
C....is truck centers in feet.
D....is distance between Bolster Center and nearest Truck Center of car in feet.
R....is radius of one degree curve in feet ( 5,729.65 feet ).
See Midordinate Offset and Endswing Offset for application of " T " Value in obtaining net MO and net EO.
UNEQUAL END OVERHANG: Load longitudinally extending beyond truck or bolster centers by unequal distances at each end.
UNIVERSAL MACHINE LANGUAGE EQUIPMENT REGISTER ( UMBLER ): A computerized file maintained by the Association of American Railroads, Transportation Division that contains specific data on outside and inside ( or platform ) dimensions including pulling face length and truck center distance, center of gravity of car, number of axles, car capacities, light ( tare ) weight of car and most recent date of weighing, and other data for each railroad car ( carrier or industry owned ) that is used in interchange service.
VERTICAL: Parallel to plumb line, perpendicular to horizon or level line. Track Centerline, as viewed in upright plane, should not be confused with vertical for obstructions in curves where there is track superelevation.
VESSEL: A hollow or concave utensil for containing something. Most excess dimension load vessels are cylindrical in shape.
WELL CAR: A specially designed flat car having an opening through the load carrying platform to facilitate the handling of exceptionally high loads or loads with high centers of gravity. The load is suspended by the car frame at a minimum clearance Above Top of Rail.
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