Rail terminology is a form of

technical terminology Jargon is the specialized terminology associated with a particular field or area of activity. Jargon is normally employed in a particular communicative context and may not be well understood outside that context. The context is usually a partic ...

. The difference between the American term ''railroad'' and the international term ''railway'' (used by the International Union of Railways and English-speaking countries outside the United States) is the most significant difference in rail terminology. These and other terms have often originated from the parallel development of rail transport systems in different parts of the world. In English-speaking countries outside the United Kingdom, a mixture of US and UK terms may exist. Various global terms are presented here. Where a term has multiple names, this is indicated. The abbreviation "UIC" refers to standard terms adopted by the International Union of Railways in its official publications and thesaurus.

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Amtrak Regional viewed from NJ Transit train

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Garratt articulated steam locomotive -- concept diagram

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; Harmonic rock or harmonic rock and roll : The condition of locomotives and cars swaying in opposite directions when traversing depressions on the roadbed. A potentially dangerous condition that can cause coupler damage, lading damage, or derailments at slower speeds. ; Head-End Power : A scheme whereby the locomotive engine or a separate generator provides hotel power to carriages ; Headboard : A sign attached to a locomotive to identify a named train or charter, or for other special occasions ; Headstock : A transverse structural member located at the extreme end of a rail vehicle's underframe. The headstock supports the coupling at that end of the vehicle, and may also support buffers, in which case it may also be known as a " buffer beam". ; Heavy haul : Heavy freight operations ;

High rail High rail (also called "hi-rail" and "hirail") is a phrase used in model railroading in North America, mostly in O scale and S scale, to describe a "compromise" form of modelling that strives for realism while accepting the compromises in scale a ...

: The upper rail in a curve or superelevation, which typically experiences higher lateral loads and greater wear ; Hole : A passing siding. Inferior trains "lay over in the hole" to let superior ones pass. ; Home signal : See absolute signal. ; Horn blocks : Plates lining the axlebox cut-outs in a locomotive frame to allow smooth vertical movement under control of the springs ; Hostling : The action of shuttling a locomotive from the yard to the engine house or vice versa ; Hotbox : An axle bearing that has become excessively hot due to

friction Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction: *Dry friction is a force that opposes the relative lateral motion of ...

; Hotbox detector : A device attached to the track that monitors passing trains for hot axles, and reports results via radio transmission (typical in the US) or a circuit to the signal box (typical in the UK). See ''

defect detector A defect detector is a device used on railroads to detect axle and signal problems in passing trains. The detectors are normally integrated into the tracks and often include sensors to detect several different kinds of problems that could occur. ...

''. ; Hudson type : WheelArrangement 4-6-4

A steam locomotive with a 4-6-4 wheel arrangement ; Hump : A raised section in a rail sorting yard that allows operators to use gravity to move freight railcars into the proper position within the yard when making up trains of cars. This is faster and requires less effort than moving cars with a switching engine. ;

Hunting Hunting is the human activity, human practice of seeking, pursuing, capturing, or killing wildlife or feral animals. The most common reasons for humans to hunt are to harvest food (i.e. meat) and useful animal products (fur/hide (skin), hide, ...

: Swaying motion of a railway vehicle or bogie caused by the coning action on which the directional stability of an adhesion railway depends. The truck or bogie wanders from side to side between the rails, "hunting" for the optimum location based on the forces at play.

I

; Independent brake or locomotive brake : The braking system that applies or releases the brakes of a locomotive independently from its train ; Infill station or in-fill station : A

train station A train station, railway station, railroad station or depot is a railway facility where trains stop to load or unload passengers, freight or both. It generally consists of at least one platform, one track and a station building providing ...

built on an existing passenger line to address demand in a location between existing stations ;

Injector An injector is a system of ducting and nozzles used to direct the flow of a high-pressure fluid in such a way that a lower pressure fluid is entrained in the jet and carried through a duct to a region of higher pressure. It is a fluid-dynamic ...

: A device to force water into a steam locomotive's boiler by steam pressure ; Insulated rail joint (IRJ) or insulated block joint (IBJ) : Rail joints incorporating insulation to isolate individual track circuits ; Interchange : Any track or yard where rail cars are transferred from one carrier to another ; Interlocking : An arrangement of switches and signals interconnected in a way that each movement follows the other in a proper and safe sequence ; Intermodal freight transport : Moving goods by more than one type of vehicle, often achieved using shipping containers that are transferred among railroad ''flatcars'', ships, airplanes, and tractor-trailer trucks ;

Intermodal passenger transport Intermodal passenger transport, also called mixed-mode commuting, involves using two or more modes of transportation in a journey. Mixed-mode commuting is often used to combine the strengths (and offset the weaknesses) of various transportati ...

: Moving people by more than one type of vehicle ; Interoperability : Ability of a transport network to operate trains and infrastructures to provide, accept and use services so exchanged without any substantial change in functionality or performance ;

Island platform An island platform (also center platform, centre platform) is a station layout arrangement where a single platform is positioned between two tracks within a railway station, tram stop or transitway interchange. Island platforms are popular o ...

: A

railway platform A railway platform is an area alongside a railway track providing convenient access to trains. Almost all stations have some form of platform, with larger stations having multiple platforms. The world's longest station platform is at Hubbali ...

that has tracks along the full lengths of both sides

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; Jacobs Bogie : A Bogie, or truck (American), shared between two pieces of rolling stock. Cars joined with Jacobs bogies are semi-permanently joined in an articulated configuration. A weight-saving feature used on lightweight passenger trains. ; Joint bar or rail joiner : A metal plate that joins the ends of rails in jointed track ; Jointed track : Track in which the rails are laid in lengths of around 20 m and bolted to each other end-to-end by means of fishplates or joint bars ; Journal bearing : A bearing without rolling elements; a plain bearing ; Journal box : The housing of a journal bearing. See also Axlebox above. ; Jubilee type : WheelArrangement 4-4-4

A steam locomotive with a 4-4-4 wheel arrangement ;

Junction Junction may refer to: Arts and entertainment * ''Junction'' (film), a 2012 American film * Jjunction, a 2002 Indian film * Junction (album), a 1976 album by Andrew Cyrille * Junction (EP), by Basement Jaxx, 2002 * Junction (manga), or ''Hot ...

: A point at which two lines or separate routes diverge from each other

K

; Keeper : A padlock or hook securing the lever of a hand-operated switch, thereby preventing the switch points from moving as rolling stock passes over them ; Kick : To shove a car a short distance and uncouple it in motion, allowing it to roll free under gravity and/or its own inertia onto a track. Commonly practiced in bowl or

hump yards A classification yard ( American and Canadian English (Canadian National Railway use)), marshalling yard (British, Hong Kong, Indian, Australian, and Canadian English (Canadian Pacific Railway use)) or shunting yard (Central Europe) is a railway ...

to make up or break down trains or classify large numbers of cars in an expedient fashion. Differs from a flying switch in that the locomotive is pushing the car rather than pulling it when the cut is made. ; Kicker : A freight car with a defect in its brake valve that causes the entire train's brake system to go into emergency when any application is made ; Kinematic envelope (KE) : The outline of the space beside and above the track that must be kept clear of obstructions for the train to pass. This can be larger than the static clearance around an unmoving engine or car. See also: loading gauge and structure gauge ; Knuckle : The articulating part of a coupler that locks automatically in its closed position to join rail cars; so named because its movement resembles that of the human finger

L

; Lead track : A non-main track from which several others branch within a short distance, such as within a

rail yard A rail yard, railway yard, railroad yard (US) or simply yard, is a series of tracks in a rail network for storing, sorting, or loading and unloading rail vehicles and locomotives. Yards have many tracks in parallel for keeping rolling stock or ...

or engine terminal ;

Level crossing A level crossing is an intersection where a railway line crosses a road, path, or (in rare situations) airport runway, at the same level, as opposed to the railway line crossing over or under using an overpass or tunnel. The term a ...

(LC), railroad crossing, railway crossing, train crossing, or grade crossing : A crossing on one level ("

at-grade intersection An intersection or an at-grade junction is a junction where two or more roads converge, diverge, meet or cross at the same height, as opposed to an interchange, which uses bridges or tunnels to separate different roads. Major intersections a ...

")—without recourse to a bridge or tunnel—generally of a railway line by a road or path. Not to be confused with non-dead-end railways (see Rail crossing) ; Light engine : A locomotive travelling on its own, or perhaps with just a caboose ( brake van) attached ; Light rail : A city-based rail system based on

tram A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport ...

design standards that operates mostly in private rights-of-way separated from other traffic but sometimes, if necessary, mixed with other traffic in city streets. Light rail vehicles (LRVs) generally have a top speed of around though mostly operating at much lower speeds, more akin to

road vehicle A vehicle (from la, vehiculum) is a machine that transports people or cargo. Vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses, mobility scooters for disabled people), railed vehicles (trains, trams), water ...

s. Light rail vehicles usually run on trackage that weighs less per foot (due to a smaller track profile) than the tracks used for main-line freight trains; thus they are "light rail" due to the smaller rails usually used. ; Link and pin : An obsolete method of coupling rail cars, consisting of manually dropping the coupling pin into the drawbar as the cars joined. Extremely hazardous to the brakemen of its day, it was outlawed in the United States by the

Railroad Safety Appliance Act The Safety Appliance Act is a United States federal law that made air brakes and automatic couplers mandatory on all trains in the United States. It was enacted on March 2, 1893, and took effect in 1900, after a seven-year grace period. The act ...

of 1893. ; Local train : A train that stops at most, if not all, stations along its route ; Lunar : An off-white color of

railway signal A railway signal is a visual display device that conveys instructions or provides warning of instructions regarding the driver’s authority to proceed. The driver interprets the signal's indication and acts accordingly. Typically, a signal mi ...

light, like the

Moon The Moon is Earth's only natural satellite. It is the fifth largest satellite in the Solar System and the largest and most massive relative to its parent planet, with a diameter about one-quarter that of Earth (comparable to the width of ...

, achieved by the use of a clear lens of very light blue, to make it distinct from a light that has a broken lens.

M

; Maglev : A system of high speed train transportation that uses two sets of magnets: one set to repel and push the train up off the track, and another set to move the elevated train ahead, taking advantage of the lack of friction. ; Main generator : The

electric generator In electricity generation, a generator is a device that converts motive power ( mechanical energy) or fuel-based power (chemical energy) into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, g ...

in a diesel-electric locomotive that is coupled directly to the prime mover and feeds electrical energy to the traction motors ; Main reservoir : The compressed-air tank of a locomotive containing source air for the brakes and other pneumatic appliances ; Mallet : A type of articulated locomotive designed by the Swiss mechanical engineer Anatole Mallet (pronounced "mallay"). See Compound engine. ; Manifest : An express freight train carrying a variety of general merchandise ; Mars Light : A nose-mounted mechanically oscillated light used to warn traffic of an approaching locomotive. Functionally replaced by ditch lights on modern locomotives. ; Mechanical semaphore signal : A signal in which the aspect is conveyed by moving an arm ; Meet : In rail transport operations, a meet occurs when two trains arrive at a location and pass each other on parallel tracks, such as on a siding, usually in opposing directions. This is also sometimes referred to as a crossing of two trains. ; Mikado type : WheelArrangement 2-8-2

A steam locomotive with a

2-8-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of two leading wheels on one axle, usually in a leading truck, eight powered and coupled driving wheels on four axles and two trailing w ...

wheel arrangement ; :In the U.S., milk trains ran from the countryside to cities making numerous stops at minor depots to pick up cans of fresh milk, making them a colloquial expression for a very slow train. : In the U. K., an aggregator for transporting milk from farms to dairies, such as British Railways Milk Trains; as these trains invariably ran very early in the morning, "milk train" became a colloquialism for a particularly early train. ; Modalohr : An inter-modal car ; Mogul type : WheelArrangement 2-6-0

A steam locomotive with a 2-6-0 wheel arrangement ; Mothballed : A track that is still serviceable but no trains are running on them. ; Mountain type : WheelArrangement 4-8-2

A steam locomotive with a

4-8-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels, eight powered and coupled driving wheels and two trailing wheels. This type of steam locomotive is commonly know ...

wheel arrangement ; Mud ring : The bottom of the water space surrounding a steam locomotive's firebox that collects solids precipitating from the water supply during the boiling process ; Multiple aspect signalling : A system of colour-light signalling in which signals may show three or four aspects ;

Multiple unit A multiple-unit train or simply multiple unit (MU) is a self-propelled train composed of one or more carriages joined together, which when coupled to another multiple unit can be controlled by a single driver, with multiple-unit train cont ...

(MU) : A self-propelled rail vehicle that can be joined with compatible others and controlled from a single driving station. The sub-classes of this type of vehicle; Diesel Multiple Unit (DMU),

Diesel-Electric Multiple Unit A diesel multiple unit or DMU is a multiple-unit train powered by on-board diesel engines. A DMU requires no separate locomotive, as the engines are incorporated into one or more of the carriages. Diesel-powered single-unit railcars are al ...

(DEMU) and Electric Multiple Unit (EMU) are more common terms. These may also be termed

railcar A railcar (not to be confused with a railway car) is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a dri ...

N

; Narrow gauge : Railroad track where the rails are spaced less than apart, ; Northern type : WheelArrangement 4-8-4

A steam locomotive with a

4-8-4 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of four leading wheels on two axles, eight powered and coupled driving wheels on four axles and four trailing wheels on two axles. The type w ...

wheel arrangement, also known in North America as "Pocono", "Niagara", "Confederation", "Greenbrier", and "Potomac" ; or run 8 : The eighth notch of a locomotive throttle control, indicating full power

O

; Open wagon (UIC) : A form of freight hauling car for bulk goods ; Out to foul : When equipment is placed ahead of the fouling point of a switch turnout

P

; Pacific type : A steam locomotive with a 4-6-2 wheel arrangement ; Pannier tank : A

tank locomotive A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank loc ...

where the water tanks are mounted on the boiler in pannier-like fashion ; Pantograph : An apparatus mounted on the roof of a rail vehicle to allow the collection of electric current from

overhead lines An overhead line or overhead wire is an electrical cable that is used to transmit electrical energy to electric locomotives, trolleybuses or trams. It is known variously as: * Overhead catenary * Overhead contact system (OCS) * Overhead equipment ...

; Paperwork : As a reason for delays, written instructions conveyed to a train's engineer in which the train must proceed slower than its normal speed. These instructions are either handed to the crew or recited and read back over radio. ; Pennsy : Abbreviation for the former Pennsylvania Railroad ;

Per diem ''Per diem'' ( Latin for "per day" or "for each day") or daily allowance is a specific amount of money that an organization gives an individual, typically an employee, per day to cover living expenses when travelling on the employer's business. A ' ...

(pronounced by some U.S. railroaders ''per die-um,'' not ''per dee-um'') : A fee paid by a rail company to the owner of a car (or ''wagon'') for the time it spends on the company's property : An authorized living expense payment for some workers forced away from their home terminal ; Permissive signal : A block signal whose most restrictive indication is stop and proceed. A permissive signal is identified by the presence of a number plate affixed to the mast or supporting structure. Proceeding beyond a permissive signal at stop is allowed at restricted speed if operating conditions enable a train operator to stop before reaching any train or obstruction. ; Pilot : A deflective shield affixed to the front of a locomotive to protect its wheels from on-track debris; archaically called a "cowcatcher" See also: Pilot (locomotive) : An employee qualified on the operating rules and physical characteristics of a certain section of the railroad, assisting a crew member who is not so qualified See also:

Railroad engineer A train driver, engine driver, engineman or locomotive driver, commonly known as an engineer or railroad engineer in the United States and Canada, and also as a locomotive handler, locomotive operator, train operator, or motorman, is a pers ...

; Pilot engine : The leading locomotive during a double-heading operation : An unattached locomotive driven a specified distance in front of a special train ; Pilot man : Where it is necessary to temporarily work a section of line as single track (for instance if the other track of a double-track line is out of use), a person (the pilot man) acts as the single track

token Token may refer to: Arts, entertainment, and media * Token, a game piece or counter, used in some games * The Tokens, a vocal music group * Tolkien Black, a recurring character on the animated television series ''South Park,'' formerly known a ...

. ; Piston : The moving component in the

cylinder A cylinder (from ) has traditionally been a three-dimensional solid, one of the most basic of curvilinear geometric shapes. In elementary geometry, it is considered a prism with a circle as its base. A cylinder may also be defined as an ...

of a

steam engine A steam engine is a heat engine that performs mechanical work using steam as its working fluid. The steam engine uses the force produced by steam pressure to push a piston back and forth inside a cylinder. This pushing force can be ...

internal combustion engine An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal co ...

that translates into motion the force exerted by pressurised steam or quickly-burning fuel ; Piston travel : A specified distance that a brake piston may move from its cylinder to the brake rigging. If the travel exceeds or falls short of this distance, the equipment must be set out for repair. ; Platform screen doors : Infrastructure used to separate the platform from train tracks. ; Pony truck : A two-wheel truck or bogie at the front of a locomotive ; Porch : The extended walkway at either end of a U.S. locomotive ; Porter : An employee who performs or performed (the role has now largely become obsolete) various physical duties, chiefly but not exclusively involving lifting. Various types of porter include: :* A ''baggage porter'' assisting with luggage :* An ''operating porter'' assisting with

safeworking Signalling block systems enable the safe and efficient operation of railways by preventing collisions between trains. The basic principle is that a track is broken up into a series of sections or "blocks". Only one train may occupy a block at a ...

duties :* A ''station porter'' assisting with general station duties :* A ''lad porter'' being a junior station porter ; Portion working : The practice of coupling two or more passenger trains together over common sections of their respective routes, but otherwise operating the trains separately ;

Position light signal A railway signal is a visual display device that conveys instructions or provides warning of instructions regarding the driver’s authority to proceed. The driver interprets the signal's indication and acts accordingly. Typically, a signal mi ...

A block signal in which the relative position of the lights determines the meaning ; Positive train control (PTC) : A system of functional requirements for monitoring and controlling train movements with the aim of increasing operational safety ; Possession : A period of time when one or more tracks are closed for maintenance. For the duration of the work, a person in charge of possession (PICOP) has control of the line. When work is complete the possession is relinquished and control of the line handed back to the signaller. ; Pound : The weight (and thus the cross section) of a length of rail. A heavier rail can carry heavier loads with less distortion and less damage to the rails themselves and the roadbed. ; Power : A locomotive or group of connected (MU'd) locomotives serving as the motive power for a train ; Power braking : Pulling against the train brakes at the higher end of the locomotive's power output (e.g. notches five through eight on a conventional throttle). This is considered wasteful of fuel and brake shoes, and is therefore discouraged by most operating departments. ; Prairie type : WheelArrangement 2-6-2

A steam locomotive with a

2-6-2 Under the Whyte notation for the classification of steam locomotives, represents the wheel arrangement of two leading wheels, six coupled driving wheels and two trailing wheels. This arrangement is commonly called a Prairie. Overview The ...

wheel arrangement ; Prime mover : The internal combustion engine of a diesel locomotive ; Pull apart : A rail broken from cold-related contraction ; Push pole : PushPoleSRM

A pole about long and having a diameter of and used in the United States between 1870 and the mid-1960s to push a freight car onto or off a siding or onto another track by being placed between a locomotive (on an adjacent track) and the freight car. The two ends of the poles were placed in receptacles called push pole pockets. The practice of using a push pole for switching was called "poling". ; Push–pull train : A configuration for

locomotive A locomotive or engine is a rail transport vehicle that provides the motive power for a train. If a locomotive is capable of carrying a payload, it is usually rather referred to as a multiple unit, motor coach, railcar or power car; the ...

-hauled

train In rail transport, a train (from Old French , from Latin , "to pull, to draw") is a series of connected vehicles that run along a railway track and transport people or freight. Trains are typically pulled or pushed by locomotives (often ...

s, allowing them to be driven from either end of the train, whether having a locomotive at each end or not. See also: Auto train. See

Top and tail A top-and-tail railway train has locomotives at both ends, for ease of changing direction, especially where the terminal station has no run-round loop. This is a British term. It is normal for only the leading locomotive to power the train when ...

for train with locomotives at both front and back.

R

;

Rack railway A rack railway (also rack-and-pinion railway, cog railway, or cogwheel railway) is a steep grade railway with a toothed rack rail, usually between the running rails. The trains are fitted with one or more cog wheels or pinions that mesh with t ...

, rack-and-pinion railway, or cog railway : A steep-grade railway with a toothed rack rail (usually between the running rails), used when adhesion is insufficient ; Railbus : A passenger rail vehicle (typically non-articulated or rigid frame) that derived from bus propulsion and construction technology, but may evolve into larger dimensions, performance, and characteristics similar in appearance to a light DMU railcar ;

Railcar A railcar (not to be confused with a railway car) is a self-propelled railway vehicle designed to transport passengers. The term "railcar" is usually used in reference to a train consisting of a single coach (carriage, car), with a dri ...

: A powered single unit or articulated passenger car, usually “railroad-derived” light DMU or EMU, with a driver's cab at one or both ends ; Rail crossing : The opposite of a dead-end rail, i.e. a line connecting locations accessed by other railways, often associated with the overcoming of natural obstacles, such as mountain ranges. Not to be confused with a railway crossing a road (see Level crossing) ; Railfan : A hobbyist or enthusiast of trains ;

Rail grinder A railgrinder (or rail grinder) is a maintenance of way vehicle or train used to restore the profile and remove irregularities from worn tracks to extend its life and to improve the ride of trains using the track. Rail grinders were developed ...

: A machine used to remove irregularities in the surface of the rails that may be self-powered or part of a consist ; Rail profile :

The cross section shape of rail. There are many rail profiles, often specific to individual railroads. Rails must be periodically scanned electronically, the data inspected and analysed, then re-profiled with rail grinding machines to maintain the safe and proper ''rail profile''. Rails that cannot be brought back to the proper rail profile are condemned and replaced. ; Rail squeal : A screeching train-track friction sound, most commonly occurring on sharp curves or heavy braking ; Rail tractor : A small petrol (gas) or diesel

shunting Shunting may refer to: * Ribosome shunting, a mechanism in protein biosynthesis * Shunting (rail), a rail transport operation * Shunting (neurophysiology), a concept in neurophysiology * Shunting (sailing), a maneuver for sailing upwind See a ...

(switcher) locomotive ; Railroad car : Any railroad vehicle other than a locomotive ; Railroadiana : Artifacts of railways around the world ; , railroad line, rail line, or train line : A railway route connecting two or more places or other railway routes : A railway route constructed by an organization, usually one formed for that purpose : A railway route that has an official name (notably bestowed by

engineers line reference {{Use British English, date=April 2020 An Engineer's Line Reference (ELR) is a three alpha, or four alpha-numeric, code used to uniquely identify a railway line on the main-line railway of Britain owned, or maintained, by Network Rail but officia ...

s in the UK) : A set of railway routes that are bundled for publicity purposes (e.g. a UK train operating company) ;

Railway station Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in Track (rail transport), tracks. In contrast to road transport, where the ...

Union Station from Columbus Circle, Washington, D

, a stopping point for trains, usually with passenger access ;

Railway terminal A train station, railway station, railroad station or depot is a railway facility where trains stop to load or unload passengers, freight or both. It generally consists of at least one platform, one track and a station building providing such ...

: A building for passengers at the end of a railway line ; Red : A colour generally associated with stop, when shown by signals or flags ; Red zone : The area between, under, or within a few feet of cars and locomotives. To enter the zone, a ground employee must obtain protection from the locomotive engineer (if a locomotive is coupled) or a blue signal (if no locomotive is coupled). ; Reefer : A refrigerated railcar, used to transport perishable goods ; : A siding used as a passing place on a main line, where slow trains may be held whilst an express passes—a simpler, but less convenient, form of the passing loop ;

Reporting mark A reporting mark is a code used to identify owners or lessees of rolling stock and other equipment used on certain rail transport networks. The code typically reflects the name or identifying number of the owner, lessee, or operator of the equip ...

: A two- to four-letter code, assigned by the Association of American Railroads, that is applied to equipment operating on North American railroads to identify the owner ; Rerail frog or rerailer : RerailFrog-SRM

A metal casting slotted over the rail near the wheel of a derailed train car. The engine then pushes or pulls the car so that the derailed wheel runs up the rerailer and back onto the track. ; Retarder : A device installed in a classification yard used to reduce the speed of freight cars as they are sorted into consists ; Reverser or reverser handle : The handle that controls the directional control on a locomotive. See also Cut off. ; Ribbon rail : Continuously welded rail ; Right-side failure : A failure in a signalling or other safety critical system that leaves the system in a safe condition ; Roadrailer : A highway trailer, or semi-trailer, that is specially equipped for direct use on a railroad ;

Rolling stock The term rolling stock in the rail transport industry refers to railway vehicles, including both powered and unpowered vehicles: for example, locomotives, freight and passenger cars (or coaches), and non-revenue cars. Passenger vehicles ca ...

: In UK parlance, any railway vehicle that is not capable of moving under its own power : In US parlance, any railroad car or locomotive ;

Rookie A rookie is a person new to an occupation, profession, or hobby. In sports, a ''rookie'' is a professional athlete in their first season (or year). In contrast with a veteran who has experience and expertise, a rookie is usually inexperienced ...

: See

Trainee A trainee is commonly known as an individual taking part in a trainee program within an organization after having graduated from higher and technical courses. A trainee is an official employee of the firm that is being trained to the job they we ...

. ; Rotary : Short for rotary snowplow, an extreme-duty railroad snowplow used mainly in the mountain ranges of the American West ; John Street Roundhouse

Roundhouse : A circular or semi-circular structure used for storage and running maintenance of locomotives ; , punch box, or train-identification pushbuttons (

New York City Subway The New York City Subway is a rapid transit system owned by the government of New York City and leased to the New York City Transit Authority, an affiliate agency of the state-run Metropolitan Transportation Authority (MTA). Opened on October ...

) : A box or panel adjacent to a rail line at an interlocking, with several buttons for train operators to select a desired route, which is then either communicated to a signal tower where an operator fulfills the request, or switched automatically ;

Ruling gradient The term ruling grade is usually used as a synonym for "steepest climb" between two points on a railroad. More simply, the steepest grade to be climbed dictates how powerful the motive power (or how light the train) must be in order for the run to ...

: The longest or steepest grade on a division, thus setting the standard for track speeds, locomotive tonnage ratings, and train handling instructions ; Run : The action verb for the train's movement. The train ''runs'' across the track. ; Runaway : A heavy train that has lost speed control while descending a steep grade, due to either brake failure or poor preparation by the crew ; Running track : An other-than-main track, typically providing access to a yard or industry and governed by the requirements of restricted speed ; Run-round : The practice of detaching a locomotive from its train, driving it to the other end of the train and re-attaching it, to allow the train to proceed in the direction it has just come from (e.g. when it reaches its destination and forms a service in the other direction). ; Run-through power : Locomotives that remain attached to a manifest or unit train from their home rails over the tracks of a receiving railroad until the train reaches its final destination

S

; Saddle tank : A

with the water tank mounted on top of the boiler like a saddle ; Safe place : An area within the network of an operator where evacuation of passengers can be performed, depending on current operational conditions, with a minimum of risk to the passengers (e.g. stations, refuges on the line) ; Safeworking : The system of rules and equipment designed to ensure the safe operation of trains ; Sandbox : A container on locomotives and self-propelled multiple units, or trams, that run on tramways and adhesion railways. The container holds

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class ...

, which a crew can drop onto the rail to improve rail adhesion under wet, steep, or

slippery rail Slippery rail, or low railhead adhesion, is a condition of railways (railroads) where contamination of the railhead reduces the traction between the wheel and the rail. This can lead to wheelslip when the train is taking power, and wheelslide ...

conditions. The sandbox and operating mechanism are collectively known as ''sanding gear''. ; Sandite : Consists of a mixture of

aluminium Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It ha ...

, and a unique type of adhesive, used instead of plain

for extreme

conditions ; Santa Fe type : WheelArrangement 2-10-2

A steam locomotive with a 2-10-2 wheel arrangement, named for the

Atchison, Topeka and Santa Fe Railway The Atchison, Topeka and Santa Fe Railway , often referred to as the Santa Fe or AT&SF, was one of the larger railroads in the United States. The railroad was chartered in February 1859 to serve the cities of Atchison and Topeka, Kansas, and ...

—the first railroad to use such a configuration ; Saturated locomotive : A steam locomotive not equipped with a superheater; the steam thus remains at the same temperature as the water in the boiler ; Scale : Solid debris distilled from boiling water in a steam locomotive. To prevent corrosion damage from scale build-up, the locomotive must undergo a boiler wash once each operating month. ; Schnabel car : A specialized type of freight car for extra heavy and oversized loads where the car is loaded in such a way that the load forms part of the car superstructure ;

Searchlight A searchlight (or spotlight) is an apparatus that combines an extremely luminosity, bright source (traditionally a carbon arc lamp) with a mirrored parabolic reflector to project a powerful beam of light of approximately parallel rays in a part ...

: A signal with a single light source usually capable of displaying three different colors. An internal mechanism governs the color displayed. ; Section : A portion of a

that may be operated independently or combined with other sections to operate as a single unit : A portion of railway line designated for signalling or maintenance : An interior portion of a sleeping car made up of two double seats during daytime that convert to two double berths during nighttime ; Semaphore signal : Rail-semaphore-signal-Dave-F

A type of signal that has a moving arm to change the indication ;

Shay locomotive The Shay locomotive is a geared steam locomotive that originated and was primarily used in North America. The locomotives were built to the patents of Ephraim Shay, who has been credited with the popularization of the concept of a ''geared s ...

: A type of geared steam locomotive built to the patents of Ephraim Shay ; Shunt : In UK and Australian parlance, to make up and divide trains in sidings, to move trains to or from sidings, or to move trains between platforms in a station ; Shoofly :Temporary track used to avoid an obstacle that blocks movement on the normal track section ; Shuttle train : A train, usually a passenger service, that runs back and forth, usually over a relatively short distance, such as between a junction station and a branch-line terminus. ; Side tank : A

with water tanks mounted each side of the boiler ; Siding : A section of track off the main line. Sidings are often used for storing rolling stock or freight. A siding is also used as a form of rail access for warehouses and other businesses, where the siding often meets up with loading docks at rail car height. In the U.S. the term also covers the British term ''

loop Loop or LOOP may refer to: Brands and enterprises * Loop (mobile), a Bulgarian virtual network operator and co-founder of Loop Live * Loop, clothing, a company founded by Carlos Vasquez in the 1990s and worn by Digable Planets * Loop Mobile, an ...

''. Also, a

passing track A passing loop (UK usage) or passing siding (North America) (also called a crossing loop, crossing place, refuge loop or, colloquially, a hole) is a place on a single line railway or tramway, often located at or near a station, where trains or ...

in the U.S. ; Signal : CSX Cum-Sub 145-MAGNOLIA-CPL-brackets-winter

A device that indicates the condition of the line ahead to the driver of a train ;

Signal box In signal processing, a signal is a function that conveys information about a phenomenon. Any quantity that can vary over space or time can be used as a signal to share messages between observers. The '' IEEE Transactions on Signal Processing' ...

: A building or room that houses signal levers (usually in a frame), a control panel or a VDU-based control system ; Signal passed at danger : An event in which a train passes a signal to stop without authorization to do so ;

Signalman A signalman is a person who historically made signals using flags and light. In modern times, the role of signalmen has evolved and now usually uses electronic communication equipment. Signalmen usually work in rail transport networks, armed for ...

: A person in charge of the signalling at a station or junction, often in a signal box ;

Slippery rail Slippery rail, or low railhead adhesion, is a condition of railways (railroads) where contamination of the railhead reduces the traction between the wheel and the rail. This can lead to wheelslip when the train is taking power, and wheelslide ...

: The condition of fallen leaves or other debris lying on and clinging to a railroad track that could cause train wheel slippage, resulting in premature wheel wear and train delays ;

Slow order A slow order is a local speed restriction on a rail line that is set below the track's normal speed limit. Slow orders are usually imposed by railway dispatchers for sections of track that are in some way deficient or when there is a requirement ...

: A local speed restriction below the track's normal speed limit often designated by yellow and green flags. Slow orders can be imposed on a temporary basis to protect, for example, maintenance of way employees while sections of track are under repair. Widely used in areas where track is substandard and in need of repair. ; Slug : A locomotive that contains traction motors yet lacks the diesel engine to create its own power, which is instead supplied by a connected mother locomotive ; Smokebox : An enclosed (normally cylindrical) space attached to the end of the boiler opposite the firebox on a steam locomotive (normally the front). Supports the stack; steam pipes to and from the cylinders pass through here; contains the blastpipe where the exhaust steam is used to provide draft for the fire. In superheated locomotives, also contains the superheater header and (optionally) a front-end throttle. ;

Snowplow A snowplow (also snow plow, snowplough or snow plough) is a device intended for mounting on a vehicle, used for removing snow and ice from outdoor surfaces, typically those serving transportation purposes. Although this term is often used to r ...

, snow plow, snowplough, or snow plough : CNR-Snow-Plough-SRM

A rail service vehicle used for snow removal from train tracks ;

Snow shed Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property. ; Span bolster : The beam between two bogies ; Spike : Railroad spikes

A bolt, pin, or nail used to hold rails, or plates connected to the rails (known as tie plates), to sleepers (ties) ; Spiral easement : See Track transition curve. Also known as tangent lead-in. ; Spreader : Jordan-Spreader-SRM

Maintenance of way equipment designed to spread or shape ballast profiles, remove snow, clean and dig ditches as well as trim embankments ; Spur line : A very short branch line may be called a spur line. ; Self-propelled ultrasonic rail testing (SPURT) (India) : A self-propelled rail-defect detector car ; Staff and ticket : A method of safeworking involving a

; Standard gauge : A gauge where the rails are spaced apart—by far the most common gauge worldwide ;

Station master The station master (or stationmaster) is the person in charge of a railway station, particularly in the United Kingdom and many other countries outside North America. In the United Kingdom, where the term originated, it is now largely historical ...

: The person in charge of a station ; Steam generator : A device generally used in passenger trains to create steam for heating. The steam generator is usually in the locomotive but may also be located in other cars. ;

Steam reverser On a steam locomotive, the reversing gear is used to control the direction of travel of the locomotive. It also adjusts the Cutoff (steam engine), cutoff of the steam locomotive. Reversing lever This is the most common form of reverser. It consist ...

: A reversing gear worked by a steam cylinder controlled from the cab ; Subdivision : The trackage area within a division covered by a single timetable ;

Supercharger In an internal combustion engine, a supercharger compresses the intake gas, forcing more air into the engine in order to produce more power for a given displacement. The current categorisation is that a supercharger is a form of forced indu ...

: A mechanical device that boosts the pressure of engine intake air to above atmospheric level, causing an increase in power. Not to be confused with the blower used to scavenge the cylinders of a naturally aspirated two-stroke Diesel engine. ; Superelevation : Areas on curves where the outside rail is elevated higher than the inside rail, creating a banked curve, generally allowing higher speeds and more comfort for passengers (on passenger trains). ;

Superheater A superheater is a device used to convert saturated steam or wet steam into superheated steam or dry steam. Superheated steam is used in steam turbines for electricity generation, steam engines, and in processes such as steam reforming. There ...

: A device in a steam locomotive that raises the temperature of saturated steam substantially beyond the boiling point of water, increasing power and efficiency ; Survey : To determine the position of constructed objects, including rail infrastructure, in relation to the earth's surface. This is accomplished by measuring angles and distances based on the principles of triangulation. ; Surveyor : A person assigned to perform survey work ; Switchback or

zig zag A zigzag is a pattern made up of small corners at variable angles, though constant within the zigzag, tracing a path between two parallel lines; it can be described as both jagged and fairly regular. In geometry, this pattern is described as a ...

: A method of climbing and descending steep gradients, where shallow-gradient track reverses direction for a while, and then reverses again to continue in the original direction ; Switchman : A railroad worker responsible for assembling trains and switching railroad cars in a yard

T

; Tamping machine : Rail track tamper - DR73238 - Jarvis Fastline livery - Chester railway station - 2005-10-09

Generally, a locomotive used in track maintenance and equipped with track lifting facilities, and paddles that push ballast beneath a rail track to assure its level and cant ;

Tank car A tank car ( International Union of Railways (UIC): tank wagon) is a type of railroad car (UIC: railway car) or rolling stock designed to transport liquid and gaseous commodities. History Timeline The following major events occurred in ...

: A type of rolling stock designed to transport liquid and gaseous commodities ;

Tank locomotive A tank locomotive or tank engine is a steam locomotive that carries its water in one or more on-board water tanks, instead of a more traditional tender. Most tank engines also have bunkers (or fuel tanks) to hold fuel; in a tender-tank loc ...

or Tank engine : A steam locomotive that carries its water in one or more on-board water tanks rather than in a separate tender. ; Team track : A spur or siding for loading freight, often used by firms not having their own direct rail access ; Tender : A specialized rail car attached to a steam locomotive to carry its fuel and water supplies, along with tools and flagging equipment ; Terminal railroad (or terminal railway) : A company in the United States that owns no cars of its own and transports only the railroad cars of other companies around a specific terminal station ; Texas type : WheelArrangement 2-10-4

A steam locomotive with a 2-10-4 wheel arrangement ;

Third rail A third rail, also known as a live rail, electric rail or conductor rail, is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway ...

: An electrified rail that runs along the tracks, giving power to trains. Used mostly in subways and

rapid transit Rapid transit or mass rapid transit (MRT), also known as heavy rail or metro, is a type of high-capacity public transport generally found in urban areas. A rapid transit system that primarily or traditionally runs below the surface may be ...

systems. ; Through coach : A passenger coach that is disconnected from one train and attached to another before continuing on with its journey, thus avoiding the need for passengers themselves to switch trains ; Through platform : The standard platform and track arrangement at a station. The train pulls alongside the platform, arriving from one end of the station, and may pass out the other end of the station by continuing along the same track ; Tie plate : A plate bolted to sleepers to hold the rails in place ; Trailer on flat car (TOFC) : Intermodal freight transport ;

Token Token may refer to: Arts, entertainment, and media * Token, a game piece or counter, used in some games * The Tokens, a vocal music group * Tolkien Black, a recurring character on the animated television series ''South Park,'' formerly known a ...

: A physical object given to a locomotive driver to authorize use of a particular stretch of single track ; Track bed or trackbed : The foundation of rail tracks ; Track bulletin : A form used by railroad employees that shows the locations of

slow order A slow order is a local speed restriction on a rail line that is set below the track's normal speed limit. Slow orders are usually imposed by railway dispatchers for sections of track that are in some way deficient or when there is a requirement ...

s, maintenance of way work locations, and other conditions affecting the track and movement of trains ;

Track circuit A track circuit is an electrical device used to prove the absence of a train on rail tracks to signallers and control relevant signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind ...

: An electrical circuit that detects the presence of locomotives or cars (as their wheelsets electrically bond the rails) in a block of track, and provides real-time input to signaling logic ; Track transition curve : The gradual application of superelevation and tighter curve radius, calculated with reference to the anticipated line speed and the final curve radius, on the approach to a bend. Also known as the ''transition spiral'' and ''spiral easement''. ;

Track Warrant Control A track warrant is a set of instructions issued to a train crew authorizing specific train movements. The system is widely used in North America. The warrant is issued by the train dispatcher and delivered to the train crew via radio. The train cr ...

: Control of train movements by "track warrants" which are sets of instructions issued to a train crew authorizing specific train movements. ; Trackside objects : See

Wayobjects Rail terminology is a form of technical terminology. The difference between the American term ''railroad'' and the international term ''railway'' (used by the International Union of Railways and English-speaking countries outside the United Sta ...

. ;

Traction current pylon A traction current pylon is a railroad pylon carrying at least one circuit for traction current. In Germany, traction current lines with two systems (4 conductor cables) typically have a single level arrangement of the conductor cables. For trac ...

;

Traction motor A traction motor is an electric motor used for propulsion of a vehicle, such as locomotives, electric or hydrogen vehicles, elevators or electric multiple unit. Traction motors are used in electrically powered rail vehicles ( electric multip ...

: A large electric motor that powers the driving wheels of an electric or diesel-electric locomotive ; Tractive effort : The pulling or pushing

force In physics, a force is an influence that can change the motion of an object. A force can cause an object with mass to change its velocity (e.g. moving from a state of rest), i.e., to accelerate. Force can also be described intuitively as a ...

exerted by a locomotive or other vehicle ;

Trailing Trailing can mean, among others: * Facing and trailing, in railroads * The act f using a Trailer (promotion) * Trailing wheel * Trailing arm * Trailing edge * Hound trailing Hound trailing, or hound racing, is a dog sport that uses specially b ...

: A turnout where both legs merge in the direction of travel—the opposite of facing ; Train bell : In North American practice, the warning bell on a locomotive or any autonomous railway vehicle ; Train coupler : The mechanical interface that links vehicles so a driver can operate them together. The coupler can be a purely mechanical device such as a screw coupler or bar coupler. Alternatively the coupler can also incorporate electrical or pneumatic connections. ; Train horn : The warning horn in a locomotive or in a control car ;

Trainman is a Japanese movie, television series, manga, novel, and other media, all based on the purportedly true story of a 23-year-old ''otaku'' who intervened when a drunk man started to harass several women on a train. The ''otaku'' ulti ...

: An employee assigned to train service, such as a conductor, brakeman, or switchman ; Train inauguration : The automated process of train bus configuration that includes detecting all bus nodes and their orientation, assigning the numbers to particular bus nodes and collecting their properties. ; Train operation and management : The procedures and related equipment enabling a coherent operation of the different structural subsystem, both during normal and degraded operation, including in particular train driving, traffic planning and management ; , terminal manager, or road manager : An employee who supervises operations over a given territory ; Train order : The process whereby signallers or dispatchers can change the order or timing of trains to maximise overall train service performance in real time ; Train set : A toy train with its tracks, buildings, etc. ; Trainset : A group of

rolling stock The term rolling stock in the rail transport industry refers to railway vehicles, including both powered and unpowered vehicles: for example, locomotives, freight and passenger cars (or coaches), and non-revenue cars. Passenger vehicles ca ...

that is permanently or semi-permanently coupled together to form a unified set of equipment. Trainsets are most often used in passenger train configurations. ;

Tram A tram (called a streetcar or trolley in North America) is a rail vehicle that travels on tramway tracks on public urban streets; some include segments on segregated right-of-way. The tramlines or networks operated as public transport ...

: A city-based rail system that typically shares its operational space with other vehicles and often runs on, across, or down the center of city streets ;

Tram-train A tram-train is a type of light rail vehicle that meets the standards of a light rail system (usually an urban street running tramway), but which also meets national mainline standards permitting operation alongside mainline trains. This al ...

s that are designed to run both on the tracks of a city-based rail system and on the existing

railway Rail transport (also known as train transport) is a means of transport that transfers passengers and goods on wheeled vehicles running on rails, which are incorporated in tracks. In contrast to road transport, where the vehicles run on a p ...

networks. Tram-trains' dual-voltage capability makes it possible to operate at lower speeds on city streets and at over on main line tracks allowing travel in an extended geographical area without changing the method of transport. ;

Treadle A treadle (from oe, tredan, "to tread") is a mechanism operated with a pedal for converting reciprocating motion into rotating motion. Along with cranks, treadmills, and treadwheels, treadles allow human and animal machine power in the a ...

: A mechanical or electrical device for detecting the presence of a rail vehicle with pin-point accuracy, unlike a

track circuit A track circuit is an electrical device used to prove the absence of a train on rail tracks to signallers and control relevant signals. An alternative to track circuits are axle counters. Principles and operation The basic principle behind ...

, which provides detection over an arbitrary distances ; Turnout or

points Point or points may refer to: Places * Point, Lewis, a peninsula in the Outer Hebrides, Scotland * Point, Texas, a city in Rains County, Texas, United States * Point, the NE tip and a ferry terminal of Lismore, Inner Hebrides, Scotland * Points ...

: A switch ; Turntable : A section of track that rotates to let locomotives and rolling stock turn around or access several engine maintenance sidings in a small area

U

; Unit train : A train in which all cars (wagons) carry the same commodity and are shipped from the same origin to the same destination, without being split up or stored en route

V

; Vactrain : A proposed design for very-high-speed rail transportation. ; Vacuum brake : A continuous train brake that is fail-safe in operation. It is powered by a

vacuum A vacuum is a space devoid of matter. The word is derived from the Latin adjective ''vacuus'' for "vacant" or " void". An approximation to such vacuum is a region with a gaseous pressure much less than atmospheric pressure. Physicists often ...

from the locomotive but the application is actually by atmospheric pressure when the vacuum is released. Now largely superseded by the air brake. ;

Valve gear The valve gear of a steam engine is the mechanism that operates the inlet and exhaust valves to admit steam into the cylinder and allow exhaust steam to escape, respectively, at the correct points in the cycle. It can also serve as a reversing ...

: The linkage mechanism that operates the valve for a driving cylinder, to alternately admit steam to the cylinder and then exhaust it when the piston's stroke is nearly complete