Abbreviations for Model Railroading and Train Collector Nomenclature

COT - Clip-On-Truck

CP - custom paint

DCC - digital command control

EXC - excellent condition

FP - factory paint

LED - light emitting diode

LN - like new

LR - last run or latest run

MIB - mint in box

MOC - mint on card

MOW - maintenance of way

MR - model railroader

NA - not applicable or not available

NIB - new in box

NIC - no insert cradle (car or locomotive nest)

NIL - no insert label

NIP - new in pack

NMRA - National Model Railroad Association

NOB - no original box (an unboxed product)

NPT - no price tag

NR - narrow rib (freight car door style) or no reserve

NSC - N Scale Collector Society

OB - original box

OBP - open box product

OP - owner paint

PWD - powered

RTR or R-T-R - ready to run

TOFC - trailer on flat car

TRO - test run only

VGC - very good condition

WPT - white price tag or with price tag

WR - wide rib (freight car door style)

YPT - yellow price tag

UNPWD - unpowered (dummy or static model)

Railroad Reporting Marks (abbreviations)

Grading Scale for Model Trains and Replicas

C-10 - Mint: Unused, with all of the original factory packaging materials.

C-9 - Factory New: Unused, with all of the original factory packaging materials. May show the slightest sign of packaging rubs, handling, shipping, and/or having been test run at the factory.

C-8 - Like New: May be lightly run, and/or show signs of display and/or age. Complete, with no missing parts and all of the original factory packaging materials.

C-7 - Excellent: May display minute scratches and/or paint chips. Complete, with no missing parts and no original factory packaging materials.

C-6 - Very Good: Minor scratches and/or paint chips. May have light surface rust and may have replacement parts.

C-5 - Good: Signs of wear, with minor paint loss, and/or minor surface rust, and/or missing parts, and/or signs of heavy use.

C-4 - Fair: May display moderate paint loss, have surface scratches, and/or dented and/or missing parts. Shows signs of heavy use.

C-3 - Poor: Requires major overhaul. May be heavily scratched, very rusty, and/or missing parts. May require body work.

C-2 - Complete Restoration Required.

C-1 - Junk: Only to be used for parts.

A Compilation of Common Prototype and Model Railroading Terminology

AAR - The Association of American Railroads is a railroad trade association that establishes safety and equipment standards for North American freight railroads. 

ACC - See cyanoacrylate glue

ABS - As opposed to ordinary styrene, acrylonitrile-butadiene-styrene is a harder and more scratch resistant form of plastic.

Airbrush - A miniature paint spray gun that is typically used by artists and modelers.  Drawing air from an air compressor, an air tank, a propellant can, or a spare tire, an airbrush's highly controlled paint flow reduces the risk of obscuring fine details.

Articulated - Commonly riding on a pair of driver sets, articulated steam locomotives typically feature a pivoting lead driver set (consisting of rods, cylinders, and drivers), which can swing from side to side as it negotiates curves, along with a separate rear driver set, which remains rigidly attached to the engine's boiler.

Balsa - Prized by modelers of operational aircraft, this lightweight wood is easily crushed and broken.

Basswood - Harder than balsa wood, basswood is a fairly light-weight, tight-grained wood that is often used in model construction.

Big Hook - A wrecking crane.

Block - An electrically isolated track section that facilitates multiple train operation.

Board and Batten Siding - Structural siding that consists of wide, butt jointed, vertical wood planking, with joints that have been covered by wooden strips (battens). 

Bolster - Trucks are attached to these cross-members, which are found under each end of a railway car body.  Bolsters are positioned near both ends of a car's underframe.

Branch - Tracks that diverge from a mainline in order to reach another railway line, and/or serve a town and/or industry

Bumper - Positioned at the end of track sidings, these devices prevent cars and locomotives from running off of the end the track.

Butt Joint - Material surfaces that have been joined end to end without any overlapping.

Caboose - Found at the end of a freight train and primarily utilized as a crew's quarters, a caboose is sometimes called a bobber, crummy, or way car.

Caliper - A precision, calibrated measuring tool that is used to measure thicknesses or distances between surfaces.

Can Motor - A motor with a sealed motor casing (i.e., an unexposed motor armature).  Can motors typically draw less amperage, and run cooler and smoother than their open frame counterparts.

Cardstock - A generic term for laminated paper sheet material.

Casting - Produced from a mold, a copy of an original part that is fabricated out of molten metal, molten plastic, plaster, or polyurethane.

Catenary - The overhead wires that provide the power used to propel non-third rail pickup equipped electric locomotives, interurbans, and trolleys.

Chemically Blackened - Chemically blackened metal has is bathed in a chemical solution, which produces an off-black or dark brown finish.  For improved realism, railway models that are equipped with metal wheels are often fitted with chemically blackened wheel sets.

Circa - About or around (e.g., A manufacturing date and/or a product or subject's era).

Clip-On-Truck - An ill conceived 1970's innovation, which made a short appearance in the marketplace due to fragility, Kadee® Micro-Trains® clip-on-trucks were attached to a freight car chassis by integrated plastic mounting ears, rather than conventional truck bolster pins.

Coaling Station - A structure where steam locomotives can take on coal.

Coaling Tower - A tall structure where coal is hoisted up to elevated storage bins and dumped through chutes into a steam locomotive's tender.

Coaling Trestle - An elevated structure where coal is dumped into storage bins from railroad cars or trucks.

Code - Rail code numbers refer to the actual height of the rail, as measured in thousands of an inch.

Craftsman - Designed for the experienced model builders, these multi-media kits often include detailed drawings, plans, and/or templates, along with unpainted wood, polyurethane, plastic, and/or metal parts.

Creosote - Distilled from coal tar, creosote is an oily liquid that is primarily used as an exterior  wood preservative.   

Cribbing - A layered  lattice of concrete, logs, steel, or timber that is often filled with earth or stones, cribbing is used in the construction of bridge abutments, dams, foundations, retaining walls, etcetera.

Crossing - A place where railroad tracks intersect or roadways cross railways.

Cut - A trench that has been blasted or excavated through a hill or mountain to maintain a level railroad right of way.

Cyanoacrylate (ACC) Glue - Also called ACC (alphacyanoacrylate), this extremely fast-setting (in minutes or seconds) glue is available in various viscosities.  The thinner the viscosity, the faster the set time.  As ACC is readily able to bond a user's eyes or skin instantly, extreme caution must always be used with this type of adhesive.

Die Cast - Products that have been manufactured using a casting process in which molten metal is forced into a mold.

Diorama - Typically used for display, modelers often super-detail these small scenes, or cutaways of structures and/or vehicles.

Directional Lighting - Headlamps that are lit in the direction of travel.  In some cases, red taillights may also be visible at the tail end of a model.

Draft Gear - The boxes located under each end of a railway car or locomotive, which contain shock absorbing spring mounted couplers.  In non-talgo truck installations, the draft gear is attached to the car body, or a locomotive pilot.

Dry Brushing - A weathering technique where paint is lightly applied to a material's raised surfaces using a nearly "dry brush," which has been wiped off, after having been dipped in a very minute amount of paint.  Dry brushing is often used to emphasize fine details.

Easy Build - Requiring very basic modeling tools, these simple, "easily assembled" kits are often pre-colored.

Elevation - On a drawing or set of plans, a single side view of a structure, or the vertical rise above a given level or grade.

Epoxy - Available in a number of different set times, this two-part (hardener and resin) adhesive is durable, and appropriate for porous and non-porous materials.

Fiddle Yard - A hidden arrangement of model railway yard tracks that are used to manipulate, stage, and store trains. 

Flange - The extended inner edge of a railway wheel, which guides its path along the rails. Incorporating low profile rails (i.e., track of a smaller code) may require the use of smaller wheel flanges.

Flash - To be removed from finished parts, flash is excess casting material that has leaked out from the gaps between mold sections.

Flywheels - When incorporated in model train locomotives, these circular metal weights improve low speed operation, while allowing a train to coast, rather than abruptly slow down, or stop, when the throttle speed is reduced, or switched off.

Frog - Positioned at track intersections, frogs permit railway wheels and flanges to cross or branch off to another track. 

Gauge - The distance between the rails as measured from the inside of each railhead.  Formerly the standard center-center spacing for wagon wheels, American "standard gauge" is 4 foot 8-1/2 inches, while "narrow gauge" (defined as anything less than standard gauge) often measures 2 - 3 feet.

Grab Iron - Steel hand rails found on the sides, ends, and roofs of locomotives and cars.

Grain - The pattern, direction, and/or arrangement of fibers in a piece of card stock or wood.

Head End Cars - Normally attached to the front of a passenger train, baggage, mail, railway post office, and express refrigerator cars are examples of head end cars.

Helper Engine - An additional locomotive called a "helper engine" may be added to a train consist in order to provide the extra power needed to surmount steep grades

Hotbox - A journal bearing box that has overheated due to the excessive friction generated by foreign matter or inadequate lubrication.

Hydrocal - U.S. Gypsum Corporation's trade name for its lightweight and very dense plaster.

Interchange  - Junction tracks that permit trains or rolling stock to reciprocally travel from one railroad to another.

Interlocking Tower - Often called signal or switch towers, these elevated railroad structures house mechanical or electrical signal and turnout control equipment.

Interurban - Drawing power from overhead lines, or a third rail that is located alongside the track, these self propelled, electric passenger railcars connected cities or towns.

Journal - The portion of an axle that is contained by a bearing.
 

Journal Box - Found on railway trucks, these housings contain a journals and bearings.

Kitbash(ed) - An new model that is constructed from the parts of two or more existing kits.

Knuckle Coupler - Designed to look like prototypical railway couplers, both operational (e.g., Accurail® Accumate, Kato, and Micro-Trains® Line Magne-Matic®) and non-operational dummy (e.g., Intermountain Railway Co. and Model Die Casting Inc. Roundhouse Products®) versions can be found on N scale models.

Lap Joint - Typically used to produce a flush or continuous surface, lap joints are created by joining the overlapping the ends of two boards of wood.

Less-Than-Carload (LCL) - Freight shipments that are smaller than the volume of a full car load.

Lintel - Fashioned out of concrete, stone, or wood, these horizontal structural members are located above door and window openings.

Main Line - The most heavily traveled sections of a railroad.

Maintenance of Way (MOW) - Rolling stock or structures utilized in maintaining a railroad, and/or repairing and/or salvaging wrecked trains.

Modules - Portable sections that can be joined to others to form a complete operating model train layout.

Mortise and Tenon Joint - Joints that are formed by cutting a hole, grooving, notching, or slotting a piece of wood (mortise) to receive another piece of wood that has a protrusion on one end (tenon)

Motor Tool - A battery or AC powered hand-held motorized tool mounted with an interchangeable collet that can be fitted with drill bits, or other kinds of cutting, grinding, milling, and polishing tools.

Muntin (Glazing Bar) - A strip of metal or wood that retains the glass panes within a window.

Narrow Gauge - Defined as anything less than a standard railway gauge

N-TRAK - Run by volunteers, the nonprofit N-TRAK Modular Railroading Society developed the wildly popular modular standard that is globally used by numerous groups and individuals to promote N scale model railroading. http://www.ntrak.org/

NMRA - Dedicated to the development, enjoyment, and promotion of model railroading, The National Model Railroad Association is a huge multi-scale model railroad organization. http://www.nmra.org/

NSC - Run by volunteers, the N Scale Collector Society is devoted to preserving the history of N Scale Model Railroading . http://www.nscalecollector.com/

Nut, Bolt, and Washer Casting (NBW) - Castings that are meant to simulate the end of a rod, with an attached washer and nut.

Open Frame Motor - A motor with an open casing (i.e., an exposed motor armature).  Older open frame motors typically draw more amperage, tend to run hotter, and are not as smooth (due in part to few and often non-skewed armature segments) as their modern sealed can counterparts.

Pantograph - A roof-mounted electric pickup device used by non-third rail pickup equipped electric locomotives, Interurbans, and trolleys.

Parting LIne - The residual mark or ridge that is produced by the joining of mold halves.

Pedler Freight Train - A freight train that switches cars at most of the towns along its route.

Piggyback - A highway trailer that is carried on a railway flatcar (see TOFC abbreviation).

Pike - A model train layout or a railway scene.

Pilaster - A rectangular, non-load-bearing, decorative column or pillar, which typically has a base and capital.

Points - A turnout's tapered and movable rails, 

Polyurethane or Urethane Castings - Molded castings manufactured from liquid two-part (hardener and resin) organic or synthetic chemicals.

Prototype - The actual subject upon which a model or replica is based.

Pullman - Owned and operated by the Pullman Car Company, these passenger cars typically consisted of diners,  parlors, and sleepers.

Rail Joiners - On model railways, track is joined by sliding metal connectors called rail joiners over the rail ends.

Razor Saw - A miniaturized, stiff backed, fine toothed, type of hacksaw that is used to make straight or angular cuts.

Rapido Coupler - An industry standard (like HO scale's NMRA horn hook X2F coupler) N scale hook style coupler that was originally developed by the now defunct, German manufacturer, Arnold Rapido.

Ready to Run (also RTR or R-T-R) - Completely assembled and ready for use. 

Reefer (Refrigerator Car) - Cooled by ice loaded through roof hatches, or by mechanical means, in modern times,  these insulated freight cars are used to transport frozen goods.

Resistance Soldering - Designed to concentrate intense heat at a specific point of contact, resistance soldering equipment is commonly used to assemble brass models.

Right of Way - Land that has been acquired by a railroad for erecting structures and laying down tracks.

Scale - The size of a model.  Expressed as a mathematical ratio of the prototypical dimensions (Z = 1:220 - 1.38mm to 1', N = 1:160 - 1.9mm to 1', TT = 1:120 - 1/10" to 1', HO = 1:87 - 3.5mm to 1', S = 1:64 - 3/16" to 1', O = 1:48 - 1/4" to 1', I = 1:32 - 3/8" to 1', G = 1:24 - 1/2" to 1').

Scale Lumber - Wood that has been cut to the precise scale proportions of commonly sized commercial building materials.

Schedule - An officially published timetable of railway departures and arrivals.

Scratchbuilt - Replicas constructed from basic raw materials, not from an assembled kit.  Scratchbuilt models contain very few, if any, commercially produced parts.

Scribe - To etch or scratch a mark or line into a piece of material.  Scribed materials are meant to resemble a series of individual boards.

Selective Compression - The process of retaining a structure's basic design elements, while reducing its overall size.

Snow Shed - Protective structures that are designed to shelter track from deep snow drifts.

Solder - Alloys that are melted in order to join two metal surfaces with higher melting points.

Spot - To position a railroad car at a specific location.

Sprue - The rod or frame that secures an unassembled model's molded parts.

Stripwood - Wood that has been cut to precise dimensions.  Scale lumber is categorized as stripwood.

Superelevation (Cant) - Designed to facilitate higher railway speeds, superelevation entails banking tracks in curves to minimize car sway, reduce rail and wheel wear, and redistribute loads across both rails.

Super Glue - See Cyanoacrylate glue

Styrene - Typically used in injection molding, this common form of plastic is available in a wide variety of extrusions, sheets, and strips.  Modelers often choose styrene because it is easily cut, is durable, can be worked with basic tools, and is easily painted.

Switch - Also called a turnout, a railway track section for diverting moving trains from one track to another.

Switch Machine - An electrical solenoid or motor that moves a turnout's points.

Talgo Truck - A model railroad truck frame with an attached coupler.  Although Talgo trucks will permit railway models to negotiate tighter radius curves, they are more prone to derailments when trains are pushed, rather than pulled.

Tank Locomotive - Most commonly used for switching rolling-stock, these small steam locomotives carried their own fuel and water, thereby waiving the need for an attached tender.

Tender - A support car that carries coal, fuel oil, water, or wood.  Most commonly found immediately behind a steam locomotive.

Traction - The generic term for electrically powered locomotives and self-propelled railcars like Interurbans and trolleys, which drew their electricity from third rail or overhead power lines.

Trolley - Self-propelled, electric passenger cars that typically ran on city streets, rather than between cities and towns, like Interurbans did.

Truck - Located under a car body and attached to the underframe's bolsters, a sprung frame, to which a car or locomotive's wheel sets are attached.

Turnout - Also called a switch, a railway track section for diverting moving trains from one track to another.

Turntable - Typically a pit with a rotating steel or wooden bridge that is used to turn locomotives and cars and/or position them in alignment with engine or round house tracks.

Vestibule - Often found on both ends of a passenger car body, travelers enter a car from these enclosed areas.  Vestibules also facilitate passage from one car to the next.

Weathering - To give the appearance of aging and/or simulate the effects of weather, modelers may apply chalks, India ink, paints, and/or stains to freshly decorated models.

Wheel Set - An axle and a pair of wheels.

Wye - A switch or turnout with diverging paths that curve away in opposite directions, equidistantly from a single straight track.  Also a three legged track configuration that incorporates three switches or turnouts to change a trains direction of travel.