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Journal box

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Journal box

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 US) is the most obvious difference in rail terminology (see usage of the terms railroad and railway for more information). There are also others, due to the parallel development of rail transport systems in different parts of the world.

Various terms are presented here alphabetically; where a term has multiple names, this is indicated. The note "US" indicates a term peculiar to North America, or "CA" may represent Canada while "UK" refers to terms originating in the British Isles and normally also used in former British colonies outside North America (such as Australia "AU", New Zealand "NZ", etc.). The abbreviation "UIC" refers to standard terms adopted by the International Union of Railways in its official publications and Thesaurus.[1]

Exceptions are noted; terms whose currency is limited to one particular country, region, or railway are also included.


Note: for 4-4-0, 2-6-4T, 0-4-4-0, etc. See Whyte notation or UIC classification
Definitions Points of Interest
  • 3-step protection (US): The protection given by a locomotive engineer to an employee working near, between, or under cars to which the locomotive is coupled. Step 1 - independent brake fully applied; Step 2 - reverser in neutral; Step 3 - turn off generator field (and/or notify the ground employee, depending on company-specific rules and locomotive type, that protection is provided).
  • 10 wheeler or ten wheeler (US): A steam locomotive with a 4-6-0 wheel arrangement.[2]
  • 241 (US): Procession of a train past a stop signal with verbal permission from the dispatcher (derives from Rule 241, which is used to grant such permission under certain rule sets).


Definitions Points of Interest
  • Absolute signal: a block signal whose most restrictive indication is stop. An absolute signal is identified by having no number plate or by an A-plate affixed to the mast or supporting structure. Proceeding beyond an absolute signal that is displaying a stop indication is prohibited unless authorized by a dispatcher.
  • Adhesion: the frictional grip between wheel and rail.
  • Adhesive weight: the weight on the driving wheels of a locomotive, which determines the frictional grip between wheels and rail, and hence the drawbar pull which a locomotive can exert.
  • Air brake: power braking system with compressed air as the operating medium.
  • air cushion: type of spring used in some modern passenger car suspension systems with air as the operating medium.
  • Alternator : a machine which converts mechanical energy to electrical energy and generates alternating current.
  • Alco: American Locomotive Company - the second largest builder of steam locomotives in the U.S.[3]
  • Alerter: Similar to the Dead man's switch other than it does not require the operator's constant interaction. Instead, an alarm is sounded at a preset interval in which the operator must respond by pressing a button to reset the alarm and timer if no other controls are operated. If the operator does not respond within a preset time, the prime mover is automatically throttled back to idle and the brakes are automatically applied. May also be called a 'Watchdog'.
  • All weather adhesion: the maximum adhesion that can be expected of a locomotive in all weather conditions.
  • American: A steam locomotive with a 4-4-0 wheel arrangement.[4]
  • Angel Seat or Angel's Perch: (US) A term often used when referring to the second level seats on a Cupola style caboose.
  • Angle cock: A valve affixed to each end of a piece of rolling stock that, when opened, admits compressed air to the brake pipe (or vents it to the atmosphere if air hose is detached).
  • Annett's key (UK), Annett key (AU): A large key which locks levers or other items of signalling apparatus, serving as a portable form of interlocking. With the key removed from the lock, the lever or apparatus is locked in its position. When the key is turned in the lock, it cannot be removed.
  • Anti-slide/skid: a device for detecting an automatically correcting wheel slide or skid during braking by a momentary reduction of braking force.
  • Anti-slip: electrical circuit which detects driving wheel slip on diesel and electric locomotives. The difference in current taken by a particular traction motor when wheel slip occurs causes an illuminated warning to be given to the engineer. In addition, an automatic reduction in motive power and/or partial application of locomotive brakes may be effected.
  • Apron: an area of roadway, loading and/or parking land by a railway station, often larger than a forecourt.
  • Arch tubes: tubes connected to the water-space of the boiler provided in and across the firebox in order to add extra high-temperature heating surface. They also serve to support the brick arch or equivalent.
  • Armature the rotating part of direct current electrc motor or generator. Contains a number of coils, or warning, which rotate in a magnetic field and are connected to the commutator.
  • Articulated locomotive: A steam locomotive with one or more engine units that can move relative to the main frame.[3]
  • Articulation the sharing of one truck (US) by adjacent ends of two rail vehicles.
  • Ash-pan: a feature of a locomotive which has the some form and purpose as the domestic variety, i.e., to collect the ashes which fall through the bars of the grate. The only significant difference is the size, measured in feet rather than inches.
  • Aspect: (UK) The indication displayed by a colour-light signal e.g. a yellow aspect
  • Asynchronous: an alternating current electric motor whose speed varies with load and has no fixed relation to the frequency of the supply.
  • Atlantic: A steam locomotive with a 4-4-2 wheel arrangement.
  • A-unit (US): A Diesel locomotive equipped with a full cab and control stand, and hence capable of being the lead unit in a consist. An A-unit that has MU capability is able to control other A-units with MU capability or B-units.
  • Auto brake A type of fail-safe system that uses air pressure to hold the brakes off so that in the event the air pressure is lost in the brake pipe the brakes will automatically apply.
  • Auto-brake gauge: A gauge recording the application and pressure of an automatic braking system; usually repeated in the guard's van in historic rolling stock.
  • Autocoach (UK): A passenger coach fitted with a driving cab and controls for use in an Autotrain (UK).
  • Automatic Block Signaling (ABS): A system that consists of a series of signals that divide a railway line into a series of blocks and then functions to control the movement of trains between them through automatic signals.
  • Automatic Equipment Identification (AEI) (US): Automatic tracking system using RFID technology.[3]
  • Automatic Train Control (ATC)[3]
  • Automatic train operation (ATO)
  • Automatic train protection (ATP)
  • Automatic Warning System (UK): Refers to the specific form of limited cab signalling introduced in 1948 in the United Kingdom to help train drivers observe and obey warning signals.
  • Autorack (also called auto carrier) (US): A specialized freight car for transporting automobiles.[3] Car transporter wagon / Car transporter van (UK).
  • Autotrain (UK): A branch line train consisting of a steam locomotive and passenger carriages that can be driven from either end by means of rodding to the regulator and an additional vacuum brake valve. The fireman remains with the locomotive and, when the driver is at the other end, the fireman controls the cut off and vacuum ejectors in addition to his usual duties. Also: Push-pull train, Motor train (UK).
  • Auto Train (US): A passenger train service first operated by Auto-Train Corporation and then by Amtrak between Lorton, Virginia and Sanford, Florida that carries the passengers' automobiles aboard the same train in autoracks.
  • Axle box the axle bearings of a locomotive are known as axleboxes. It is usually convenient to make them boxshaped to suit the guides and openings in the frames which should constrain movement in the horizontal plane but allow freedom vertically. see journal box below


Definitions Points of Interest
  • B end (North America): The end of a railroad freight car in North America, to which the hand brake apparatus (usually a wheel, sometimes a lever) is applied, or to which it is closest. On articulated cars with more than one unit, where there is only a brake wheel on one of the units, the unit containing the brake wheel is generally designated the "B" unit (not to be confused with a B unit locomotive), the opposite end of the articulated unit the "A" unit, and any intermediate units between the "A" and "B" designated with successive letters of the alphabet, starting with "C", and progressing in order towards the "A" unit. Thus an articulated car consisting of five units, will have the units ordered (from the "A" end, "A - E - D - C - B".
  • B unit (US): A cabless booster locomotive, controlled via MU from a cab-equipped A unit. Sometimes equipped with limited controls for hostling.[5][6][7]
  • Back shop: A maintenance structure, usually an extension of a roundhouse, used for major repair work on locomotives.
  • Bacon slicer (UK): Slang term for a cutoff controlled by a wheel operating through a worm and nut, rather than the more usual quadrant lever. The device was slow to operate, but very precise, and therefore only fitted to long-distance locomotives where frequent changes of cut-off were not required.
  • Bad order: A tag or note applied to a defective piece of equipment. Generally, equipment tagged as bad order is not to be used until repairs are performed and the equipment is inspected and approved for use.[8]
  • Bail off: 1. To release the locomotive brakes while the train brakes are being applied in order to maintain slack conditions and permit smoother handling. Also actuate. 2. To dismount moving equipment.
  • Balancing: the reciprocation and revolving masses of any steam, diesel or electric locomotive need balancing, if it is to work smoothly. Revolving masses can easily be balanced by counterweights, but the balancing of reciprocating parts is a matter of compromise and judgement.
  • Baldwin: 1. An American locomotive manufacturer in business from 1825 to 1972. 2. A locomotive built by the BLW.[8]
  • Ballast: aggregate stone, gravel or cinders forming the track bed on which sleepers (ties) and track are laid to ensure stability and proper drainage.[8]
  • Balloon: A looped length of track, usually at the end of a spur or branch, which allows trains to turn around for the return trip without reversing or shunting. Can be used as part of a freight installation to allow the loading or unloading of bulk materials without the need to stop the train (see merry-go-round train (MGR)).
  • Bank: A particularly steep section of line that requires additional bank (or banking) engines (US: helper engines) to help trains climb.
  • Banking: Assisting the working of a train, usually when ascending a gradient, by attaching one or more locomotives to the rear.
  • Base plate (UK), tie plate (US): An iron or steel plate used to spread the weight of rail over a larger area of sleeper (tie) and facilitate a secure, low maintenance, fastening with bolts or clips. It derives from the former rail chairs.
  • Bay platform: A type of platform/track arrangement where the train pulls into a siding, or dead-end, when serving the platform.
  • Bearings: The bushing or metal block of anti-friction material which transmits the load via an oil film to a journal.
  • Beep: A one-of-a-kind switcher locomotive (also referred to as the SWBLW) built by the Atchison, Topeka and Santa Fe Railway in 1970.
  • Bend the iron (slang, US): To line a switch.
  • Berkshire: A steam locomotive with a 2-8-4 wheel arrangement.
  • "Big Mac" (slang, US): A nickname for EMD's SD-90MAC locomotive model.
  • Bi-current Locomotive: Designed to operate on two different electric current frequency systems.
  • Blastpipe: A part of a steam locomotive that discharges exhaust steam from the cylinders into the smokebox beneath the chimney in order to increase the draught through the fire.
  • Blended braking: The combination of air brakes with dynamic braking to control a heavy train on a grade.
  • Blowdown valve: A means of releasing water, plus impurities contained therein, from the lowest water space of a steam locomotive's boiler.
  • Blower: On a steam locomotive, a steam pipe leading into the smokebox, causing necessary draft in the chimney (stack) when the engine is not running. However, UK practice is to turn on the blower also when entering tunnels, etc., to avoid dangerous blow-back into the cab. (The UK loading gauge is much smaller than that in the US and the tunnel roof would otherwise spoil the normal draft created from the exhaust.) On a two-stroke diesel engine, the blower is a mechanical device that scavenges the cylinders: not to be confused with a supercharger.
  • Blue signal (US): A method of on-track protection for rail cars and locomotives that are being loaded/unloaded, maintained, or serviced; typically in the form of a sheet-metal blue flag in daylight and a flashing blue light at night. Only the employee (or another employee from the same department) who placed a blue signal may remove it.
  • Bobber: (archaic, US): A slang word for a small caboose with just four wheels, all rigidly mounted to the frame. This design was common in the 19th century. Bobber refers to the bouncing action of such a caboose while in motion.
  • Bo-Bo (Europe): A locomotive with a 4 wheel per truck configuration, each individually powered, as opposed to a 6-wheel "Co-Co" configuration.
  • Bogie: (chiefly UK) The undercarriage assembly incorporating the train wheels, suspension, brakes and, in powered units, the traction motors. Generally called a truck in the US.
  • Boiler: A cylindrical container adjacent to the firebox in which steam is produced to drive a steam locomotive.[9]
  • Bolster: Transverse floating beam member of truck suspension system supporting the weight of vehicle body.
  • Bonds: Short wires used to bridge gaps in electrical circuits, usually at track circuit joints or between rails.
  • Booking Clerk: A person at a station whose job is specifically selling tickets.
  • Boom barrier: A barrier at a level (rail) crossings.
  • Booster: (Steam locomotive) - An extra set of cylinders that can be engaged to drive a trailing truck or tender truck to give additional tractive effort at starting and low speeds.[8]
  • Bowl yard, Bowl track: A classification yard with an ascending grade at both ends, which thus prevents free-rolling cars from running out the opposite end during switching operations.
  • Boxcar (US, Canada): Covered wagon (UIC): a type of rolling stock with a flat bottom enclosed on all sides and top, which is loaded and unloaded from sliding doors on each side.[8] Same as van (UK). (Also used as a verb in US railroad slang for setting up a locomotive's air brake system so it can be hauled dead-in-tow.)
  • Brakeman (US): A train crew member who performs railcar and track management; often a single job description along with switchman ("brakeman/switchman"). A brakeman manually activated brakes on railroad cars before the advent of air brakes.
  • Brakeman's cabin, brakeman's cab or brakeman's caboose (US): small hut at one end of a railway wagon to protect the brakeman from the elements.
  • Brake Pipe (US): The main air pipe of the trains pneumatic braking system.
  • Brake van (UK): A heavy vehicle with powerful brakes which was attached to the rear of goods trains in the days when most wagons were not fitted with a continuous braking system. Its function was to supplement the locomotive's braking power in slowing and stopping the train and to keep the couplings uniformly tight by selective light braking to avoid snatching and breakages. It also conveyed the train guard, hence its alternative name of "guards van". Partly analogous to caboose and its synonyms.
  • Branch line: A secondary railway line that branches off a main line.[8]
  • Brick arch: A brick or concrete baffle provided at the front of a locomotive firebox below the tubes, in order to extend the flame path. Early Locomotives burnt coke; provision of a brick arch was necessary before coal could be used without producing excessive smoke.
  • Broad gauge: Track where the rails are spaced more widely apart than (which is called standard gauge).[8] Many early railroads were broad gauge, for example the Great Western Railway in the UK which adopted gauge until it was converted to standard gauge in the 1860s - 1890s. Russia still has over 80,000 km (50,000 mi) of broad gauge () railroads. Broad gauge is also normal in Spain and Portugal ( Iberian gauge), in India ( Indian gauge), as well as Ireland and used in some parts of Australia ( Irish gauge).
  • BRUTE: British Rail Universal Trolley Equipment - type of platform trolley found on stations all over the UK rail network from the late 1960s to the early 1980s.
  • Brush conductor: usually of carbon providing electrical contact with a sliing surface moving relative to it such as the commutator of a direct current machine.
  • Bubble Car: A DMU consisting of a single coach (UK), e.g. British Rail Class 121
  • Buckeye coupler: A form of coupler which will lock automatically when the two parts are pushed together.
  • Buck (US): A term used for pushing railroad cars with a locomotive then allowing them to roll under their own momentum into a siding. (Assuming a brakeman hangs on for a free ride) Also; Kick. The UK equivalent was called Loose Shunting.
  • Buffer A device that cushions the impact of rail vehicles against each other.
  • Buffer stop or Bumper post: The barrier installed at the end of a dead end track to prevent rail vehicles from proceeding further.
  • Builder's plate: the nameplate on locomotives and rolling stock
  • Bulkhead flat: An open-top flatcar with a wall at each end.
  • Bull (slang, US): A railroad police officer.
  • Bull head rail (UK): A steel rail section commonly used in 60 ft lengths on almost all railway lines throughout Britain until c1950, which due to its shape must be supported in cast iron chairs that are screwed to the sleepers. It is still found on some London Underground lines, on secondary and preserved lines and in yards. The rail has two heads (shaped somewhat like a vertical dumbbell) which led some people to assume that when one side became worn, the rail could be inverted and reinstalled for further service rather than being replaced (it can't, because the two heads are different sizes, and by the time the top became worn down sufficiently to fit in the chairs when the rail is inverted, both the top and the bottom of the rail would be too small for further use).
  • bungalow (Can:S&C) Bungalow: refers to the housing for signals & communications computers that control switches, crossings, and other such controls, relaying information to and from the RTC (Rail Traffic Control)
  • Bustitution: The practice of replacing train service, whether light rail, tram/streetcar systems, or full-size railway systems, with a bus service, either on a temporary or permanent basis. Somewhat derogatory and mainly used in the UK, Canada, USA, and Australia. The word is a portmanteau of the words "bus" and "substitution".


Definitions Points of Interest
  • Cab: The "control room" of a locomotive housing the engine crew and their control consoles.
  • Cab forward: Typically refers to a steam locomotive with its cab at the leading end of the boiler, rather than the usual trailing end adjacent to the tender. The best known example is the Southern Pacific Railroad's AC type, built to handle drag freights through the SP's many tunnels and snow sheds without the danger of the exhaust asphyxiating the engine crew.
  • Cabin car (PRR): See caboose.[10]
  • Cabless: A locomotive without a cab. Commonly referred to as a B unit or a Slug, although not all Slugs are cabless.
  • Caboose: A railroad car attached usually to the end of a train, in which railroad workers could ride and monitor track and rolling stock conditions. Partly analogous to brake van (UK). Largely obsolete, having been replaced by the electronic End of Train (EOT) device, or Flashing Rear End Device called "FRED".[10]
  • Caboose hop: A train consisting of only a locomotive and a caboose.
  • Cant: Synonymous with superelevation: Angle. Can be used in the context of the cant of the track (the relative level one rail to another, e.g. on curves) (UK); and the cant of a rail, being the angle of an individual rail relative to vertical.
  • Cam: Reciprocating, oscillating or rotating body which imparts motion to another body known it is in contact.
  • Camshaft: A shift which carries a series of cams for operating the inlet values and exhaust valves of a diesel engine, and contactors in some electric traction control gear systems.
  • Canteen car: An auxiliary steam locomotive tender which carries extra water on long journeys.
  • Cape (UK): To note the cancellation of a passenger train service to employees. (From British Railways telegraphic codeword[11])
  • Carbody unit or cab unit (US): A locomotive which derives its structural strength from a bridge-truss design framework in the sides and roof, which cover the full width of the locomotive. It refers to both A units and B units.
  • Carman (US): A mechanic responsible for maintaining and inspecting the rolling stock.
  • Catenary or catenary structure: The overhead wire system used to send electricity to an electric locomotive or multiple unit, tram or light rail vehicle.[10]
  • Centerbeam: A bulkhead flatcar with a braced beam bisecting its length, used to transport lumber products.
  • Centralized traffic control (CTC) (US, AU): A system in which signals and switches for a given area of track are controlled from a centralized location. May or may not be computerized.[10]
  • Cess (UK): The area either side of the railway immediately off the ballast shoulder. This usually provides a safe area for workers to stand when trains approach.
  • Chair (UK): A cast iron bracket screwed to the sleeper and used to support bull head rail that is held in place by a wooden key (wedge) or spring steel clip. Still found on preserved railways and in yards.
  • Challenger: A steam locomotive with a 4-6-6-4 wheel arrangement.
  • Check ride: A monitor of operational skills administered annually to a locomotive engineer by a designated supervisor.
  • Ches-C (US): Chessie System's kitten logo.[12][13]
  • Chimney (UK): Smokestack or stack (US), or funnel.
  • Co-Co (EU): A heavier duty locomotive with 6 wheels per bogie (all axles being separately driven) configuration as opposed to a 4-wheel "Bo-Bo" configuration. The correct classification is Co'Co', but Co-Co is used more often.
  • Coal pusher: A steam-operated device in the tender intended to push coal forward to a point where it can be shovelled directly into the fire.
  • COFC: Abbreviation for "Container On Flat Car".[10]
  • Colour light signal: A signal in which the colour of the light(s) determine the meaning of the aspect shown.
  • Colour position signal: A signaling system that uses both colour and light position to determine the meaning of the aspect shown.
  • Combined Power Handle: A handle or lever which controls both the throttle and the dynamic braking on the locomotive: on a desktop-type control stand, forward (away from operator) past center operates the dynamic brake, backward (toward operator), past center, is throttle up.
  • Composite (UK passenger car): A passenger car with more than one class of accommodation provided, e.g. First and Third. In earlier days of three-class travel, First and Second class, and Second and Third class composites were also built. A car with First, Second and Third classes was also known as a tri-composite.
  • Compound locomotive: A steam locomotive passing steam through two sets of cylinders. One set uses high pressure steam, then passes the low pressure exhausted steam to the second.[14]
  • Compromise joint: A special joint bar used to join rail ends of two different cross-sections while holding the top running surface and inside gauge surface even.
  • Conductor (US), guard (UK): The person "in charge" of a train and its crew. On passenger trains, a conductor is also responsible for tasks such as assisting passengers and collecting tickets. In Australia, both terms are used, "conductor" for the person checking tickets, etc. on a tram or train, and "guard" for the person in charge of the train.
  • Consist (US, pronounced "KONN-sist"), formation (UK): A noun to describe the group of rail vehicles making up a train, or more commonly a group of locomotives connected together for Multiple-Unit (MU) operation.[10]
  • Consolidation: A steam locomotive with a 2-8-0 wheel arrangement.
  • Continuous welded rail (CWR): In this form of track, the rails are welded together by utilising the thermite reaction or flash butt welding to form one continuous rail that may be several kilometres long.[10]
  • Control car or Cab car: A passenger coach which has a full set of train controls at one end, allowing for the use of push-pull train operation.
  • Control Point (CP) (US): An interlocking, or the location of a track signal or other marker with which dispatchers can specify when controlling trains.[10]
  • Cornfield meet (US): A head-on collision between two trains.[15][16][17]
  • Coupler (US), coupling(UK): Railroad cars in a train are connected by couplers located at the ends of the cars.[10]
  • Coupler pulling faces, length over, effective length of piece of rolling stock.
  • Coupling rods or connecting rods: Rods between crank pins on the wheels, transferring power from a driving axle to a driven axle of a locomotive.[18]
  • Cow and calf: A diesel locomotive with a crew cab permanently coupled to and acting as a controller for a similar slave diesel locomotive without a crew cab, primarily used for switching/shunting duties for large groups of rolling stock. Also known as master and slave, as in the British Rail Class 13 shunters at Tinsley Marshalling Yard. (Cow can also refer, in S&C, to the units relaying ground wiring to signaling units)
  • Cowl unit (US): A locomotive whose sides and roof are non-structural, and cover the full width of the locomotive. Structural strength comes from the underframe.
  • Crank pin: A pin protruding from a wheel into a main or coupling rod.
  • Crew driver (US): Person(s) operating ground transportation vehicles for transporting railroad crews to and from various locations.
  • Crosshead: The pivot between the piston rod and the main rod on a steam locomotive.[19]
  • Cross-tie (U.S): sleeper (UK): See Railroad tie.
  • Cut lever: A manual lever which releases the pin of an automatic coupler when pulled to separate cars and/or locomotives.
  • Cut off: A variable device on steam locomotives which closes the steam valve to the steam cylinder before the end of the piston stroke, thus conserving steam while allowing the steam in the cylinder to expand under its own energy. Also: Reverser.
  • Cutting: A channel dug through a hillside to enable rail track to maintain a shallow gradient. See also embankment
  • Cycle braking: Making repeated service brake reductions in short succession to maintain a constant speed on short but steep grades. Each reduction must be at least 5 psi lower than the previous one in order to keep the brakes applying regularly, but excessive cycle braking can deplete the air supply and require an emergency application.
  • Cylinder: The central working part of a reciprocating engine, the space in which a piston travels.
  • Cylinder cock: On steam locomotives, this appurtenance allows condensed water to be drained from the steam cylinders when the throttle is opened, thus preventing damage to the pistons, running gear, and cylinder heads.


Definitions Points of Interest
  • Dark Signal: A block signal that is displaying no discernible aspect, often due to burned out lamps or local power failure. Most railroads require that a dark signal be treated as displaying its most restrictive aspect, e.g., stop and stay for an absolute signal.
  • Dark territory: A section of track without block signals.[20]
  • Dead in tow: The movement of a locomotive as part of a freight train, on its own wheels but not under its own power.
  • Dead man's handle or Dead man's switch: A safety mechanism on a train controller which automatically applies the brake if a lever is released. It is intended to stop a train if the driver is incapacitated. In some forms, this device may be pedal-actuated.
  • Deadhead: (US) 1. A nonrevenue (i.e., nonpaying) passenger. 2. The nonrevenue movement of locomotives and/or cars.
  • Decapod: A steam locomotive with a 2-10-0 wheel arrangement.
  • Defect detector: A track side device used to detect various defects such as hotboxes (overheated axle bearings), dragging equipment, leaning cars, overloaded cars, overheight cars, seized (locked) wheels, etc.[21]
  • Demurrage: A monetary charge levied by a railroad to a customer for excessive delay in loading or unloading cars.
  • Derail: A safety device that will derail vehicles passing it, often used to prevent rolling stock from unintentionally fouling the mainline. Sometimes incorrectly called a "derailer".[21]
  • Detonator: Small explosive charges placed on the running rail which detonate when run over; used to warn drivers in following trains of an incident ahead. Also called track torpedoes (US).
  • Diamond: Track which allows a rail line to cross another at grade.[21]
  • Diesel multiple unit or DMU: A set of diesel-powered self-propelling passenger rail vehicles able to operate in multiple with other such sets. Such units, especially those consisting of a single vehicle, are sometimes termed railcars.
  • Direct Traffic Control (DTC): A system in which train dispatchers communicate directly with train crews via radio to authorize track occupancy in predefined blocks.[21]
  • Distributed power: A practice employed to move large trains through the mountains. Consists of the locomotives on the head end, a "swing" (mid-train) helper or two, and pusher locomotive(s) on the rear; today, all units are remotely controlled by the engineer in the lead unit. The power distribution alleviates stress on the couplers and relieves the lead units of the full weight of the train, making it easier to move on grades.
  • Ditch lights: A pair of lights, usually found on modern locomotives, located several feet below and outboard of the main headlight, that may alternately flash when the train is sounding its horn.
  • Dog-catching (slang, US): Taking over a train whose crew has exceeded their hours of service.
  • DOO: Driver-only operation, also referred to as One person train operation (OPTO).
  • Doodlebug: Gasoline-electric self-powered passenger car used for small capacity rural commuter service.[21] Also a British Rail Class 153 DMU.
  • Double, as in "Double the hill": if a train has insufficient power to climb a grade and no helpers are available, the train will be split into two sections and run separately to the top.[22]
  • Double iron (slang, US): A double-tracked main line.
  • Doubleheading or Doubleheader (US): In which two steam locomotives are coupled head-to-tail in order to haul a heavy train up a long and/or steep hill. In the present day, doubleheaders (and occasionally tripleheaders) are done primarily on large passenger trains or as a show for railfans.
  • Down: (UK) A direction (usually away from London, other capital city, or the headquarters of the railway concerned) or side (on left-running railways, the left side when facing in the down direction). The opposite of up. The down direction is usually associated with odd-numbered trains and signals. In Australia it is used relative to the state's capital city. US railways use the compass points northbound, southbound, eastbound and westbound.
  • Drag: A long, heavy freight train moving at low speed.
  • Dragging equipment detector: See Defect detector[21]
  • Drawbar: 1. The part of a coupler that attaches to the frame of the car or locomotive; may be equipped with a pneumatic cushion depending on a freight car's design cargo, e.g. an autorack. 2. The pinned double bars coupling a steam locomotive to its tender.
  • Drift: To cut off power and allow a train to coast.
  • Driver (UK), Engineer (US): The operator of a railway/railroad locomotive.
  • Driver: A wheel in contact with the rail that also propels a locomotive.
  • Driving Van Trailer or DVT (UK): A class of control cars used in the UK. (See also: DBSO - predecessor to the DVT)
  • DSLE (US): abbr. Designated Supervisor of Locomotive Engineers.
  • Dwarf signal: A signal light that is considerably smaller and closer to the ground than a high-mast signal; often absolute, and placed within interlocking limits, its aspects tend to differ from those conveyed by a taller signal for certain indications. Also called 'pot' or 'jack'.
  • Dynamic braking: The use of a diesel locomotive's electrical output to maintain or retard train speed on a descending grade, without relying solely on the air brakes.
  • Dynamite (slang, US): To make an emergency brake application; also "plug" and "shoot".


Definitions Points of Interest
  • ECS: Empty coaching stock. Describes a passenger train which is not in service. For example, it may be being moved from a depot to a terminal station.
  • Ejector: Component of vacuum brake system. Steam passing through a cone sucks air from the train pipe to create the vacuum. Usually fitted in pairs: a small ejector running continuously to overcome leaks and to restore the vacuum after light braking and a large ejector operated when needed to release the brakes quickly after a heavy application or to create the initial vacuum ("making a brake" – UK) after coupling up.
  • Electric multiple unit (EMU): A set of electrically powered self-propelling passenger rail vehicles able to operate in multiple with other such sets.
  • Elephant style (US) - Railfan jargon to describe how multiple locomotives are coupled together in a train; the front of the second locomotive is coupled to the rear of the first locomotive, the front of the third locomotive is coupled to the rear of the second locomotive, and so on down the line.[23] The term is reminiscent of a parade of circus elephants where the elephant behind the front elephant would hold the leading elephant's tail in its trunk.
  • Elevated railway: One typically built on supports over city streets, commonly called "the el" or simply the "The L".
  • Embankment: A raised pathway on which rail tracks are placed to maintain a shallow gradient when passing over depressions in the terrain. See also cutting.
  • Empty Coaching Stock train, or ECS: A train used to bring carriages into (or out of) service. They usually run between sidings and main stations, with the carriages then forming a service train to another destination. They are often worked under freight train rules - e.g. without needing a guard in the UK.
  • EMD: Electro-Motive Diesel, Inc, the world's second largest builder of railroad locomotives. EMD was previously Electro-Motive Division of GM before being sold.
  • End-cab switcher: A switching locomotive with no short hood, thus having its cab forming one end of its carbody.
  • Engineer (US), driver, engine driver, train driver (UK): The operator of a locomotive.[24]
  • EOT (US): End of train device. A form of an electronic caboose also called FRED.[24]
  • EP gauge (UK): Electro-pneumatic brake gauge; recording the application and pressure of the service brake, usually repeated in the guards van in historical rolling stock.
  • Equalizing reservoir: A small air reservoir in a locomotive control stand. When the automatic brake valve is operated, this reservoir responds by reducing or increasing the air pressure in the brake pipe.
  • Event recorder - A device that continuously captures analog and digital train systems information and stores that data for a minimum of 48 hours. This data is used to evaluate incidents and accidents. Typical stored data includes speed, brake pressure, dynamic brake, horn activation, track signal, etc. In the U.S., event recorders are mandated by the Federal Railroad Administration (FRA) for freight, passenger and commuter rail. Regulations for railroad outside the U.S. vary by country. Transit operations are not generally required to have event recorders, but have begun to add them voluntarily.
  • Ex-con (US): An ex-Conrail locomotive (jargon) or former employee of Conrail. Not to be confused with the more common meaning of a convicted criminal who has been released after serving prison time.
  • Express train: A train that passes selected stations without stopping.
  • Extra train: A train that is not included in the normal schedule of a railroad. They often run during busy holiday travel periods in order to handle larger crowds and reduce the number of passengers that are forced to stand or are stranded at a station. In train order territory, extras are required to clear the main line for scheduled trains to pass.


Definitions Points of Interest
  • Facing: A turnout is facing if it can select which way to diverge a train. Opposite of trailing.
  • Fairlie: A type of articulated locomotive, typically (but not exclusively) with two boilers and connected fireboxes in a central cab.
  • Fall plate: A heavy, hinged steel plate attached in a horizontal position to the rear of the locomotive footplate or front of a locomotive tender. When the tender is attached to its locomotive the plate is allowed to fall to cover the gap in the "floor" between the two units. The sliding edge is not fixed and has a smooth chamfer so as to avoid a trip hazard.
  • Fallen flag (US): A railroad which is defunct, having either merged or discontinued operations.[25]
  • Feedwater heater: A device to preheat the water for a steam locomotive; improves efficiency.
  • Feed valve: Also regulating valve; controls the amount of air pressure being channelled from the locomotive's main reservoir to the brake pipe, in accordance with the set pressure in the equalizing reservoir.
  • Fettle, fettling: Making repairs to rail track, especially concerned with maintaining the drainage of the ballast, and the proper cant of the rail track and rails.
  • Fiddle Yard: A concealed group of sidings used in model railways to provide more realistic operation in limited space.
  • Firebox: In steam railroading, a firebox was a chamber in which a fire would produce sufficient heat to create steam once the hot gases from the firebox were carried into the adjacent boiler via tubes or flues.[26]
  • Fireman (also Stoker, Boilerman): A worker whose primary job is to shovel coal into the firebox and ensure that the boiler maintains sufficient steam pressure; a driver's assistant.
  • Fishplate (UK), Joint bar (US): A metal plate that joins the ends of rails in jointed track.
  • Flat: A wheel defect where the tread of a wheel has a flat spot and is no longer round; flats can be heard as regular clicking or banging noises when the wheel passes by. This is caused either by a locked bearing, or a brake that was not fully released before the car was moved, dragging the wheel without turning.[27]
  • Flatcar (US): A type of rolling stock, which can be a flat-bottomed car with no sides on which freight (including intermodal containers) can be stacked. A bulkhead is a flatcar with walls on the front and rear. A center-beam bulkhead is a bulkhead flatcar with an additional wall dividing one side of the flatcar from the other, but still without any sides.[27] Flat wagon (UIC, UK).
  • Flying junction, Flyover: A railway junction that has a track configuration in which merging or crossing railroad lines provide track connections with each other without requiring trains to cross over in front of opposing traffic.[27]
  • Flying switch (US): Fly shunting (UK): The practice of uncoupling a locomotive from a car in motion and running over a switch, whereupon an employee on the ground lines the switch to divert the car onto an adjacent track. Once commonplace, this practice is now strictly prohibited due to the high risk to life and property.
  • Foamer (US): A colloquial term for a railfan, specifically one whose enthusiasm is excessive, "foaming at the mouth".[28]
  • Fouling point: The point of a switch turnout where a car or locomotive on one track will obstruct movement on the adjacent track.
  • Four-Day Ray (slang, US): An employee who habitually marks off from duty on the fifth day of the work week.
  • Four-foot: The part of the line between a pair of running rails. An abbreviation for four-foot, eight-and-a-half-inches. Also see six-foot and ten-foot.
  • Four-quadrant gate: A type of Boom barrier, see above.
  • FRA: (US) The Federal Railroad Administration. This agency oversees rail operation regulations and safety requirements for U.S. freight, passenger and commuter rail operations.[27]
  • Flashing Rear-End Device (FRED) (US): A small marking device with a flashing red light mounted on the end of the train. FRED also monitors various train functions such as brake pipe pressure, motion and GPS location. A form of an electronic caboose. Also called an EOT (end of train) device.[27][29]
  • Free-mo: A type of modular layout in model railroading.
  • Freight (US) Goods (UK): the product(s) in which are carried.
  • Frog: (US) A casting with "X" shaped grooves used in switches and crossovers.[27]
  • Full service reduction: The maximum air pressure that can be exerted against brake pistons in a normal brake application. To increase pressure beyond this point, the brakes must be placed in emergency.
  • Funnel: A Thomas the Tank Engine misnomer for a chimney] (UK) or smokestack (US), although it is also used in Australia (Victoria at least). Some early steam engines had a smokestack consisting of a straight vertical flue and a funnel-shaped top, probably leading to the use of "funnel" to describe the entire stack.
  • Fusee: A pyrotechnic device similar to an automotive flare that is used for signalling.[27]
  • Fusible plug: A threaded plug, with a soft metal core, that is screwed into the crown plate of a firebox. If the water level gets too low the core melts and the noise of the escaping steam warns the enginemen.


Definitions Points of Interest
  • Gage: An alternate (US) spelling of "Gauge" as in "track or rail gage".
  • Gandy dancer (slang, US): A track maintenance worker.[30]
  • Garratt: A type of articulated locomotive.
  • Gauge: The width between the inner faces of the rails.
  • Geep: A slang term for any of the GP ("general-purpose") series of Electro-Motive four-axle diesel locomotives; originally applied only to EMD GP7, GP9, and GP18 models.[30]
  • Generator field: The control switch of a diesel-electric locomotive that opens or closes the circuit between the main generator and the traction motors.
  • GEVO: A nickname for General Electric's Evolution series of modern diesel locomotives.
  • Glad hand
    Main article: Gladhand connector
    A quick-coupling/uncoupling connector at the end of a trainline air hose that resembles a pair of "shaking hands" when hoses are connected.
  • Go-devil: A hand-powered railroad car (see Handcar and Draisine ), or a small gasoline powered railroad car .
  • Gondola: A type of rolling stock with a flat bottom and relatively low sides, used to haul material such as ore or scrap, and loaded and unloaded from the top. May be covered or uncovered. Open wagon (UIC, UK).[30]
  • Goods (UK): Freight (US): Both terms are used in Australian English
  • Goods wagon or Freight wagon (UIC): Goods wagon, Goods van or Goods truck (UK): Freight car or Box car (US, Canada): A flat car with sides and a top, usually with a large sliding door in the middle of each side.
  • Go to beans (slang, US): Train crew parlance for stopping to take a coffee or meal break during a shift.
  • Grab bar: A handle on the side of a car to allow switching personnel to hold on (also known as a "grab iron").
  • Green: A colour associated with go or proceed.
  • Guard (UK): Conductor (US) See Conductor above.
  • Gricer (UK): Railway enthusiast.
  • Gripper (UK enthusiast slang): A ticket inspector/collector; a revenue protection officer.
  • Guard rail (US) Check rail (UK): A double rail section of track, sometimes found in train yards and on bridges to prevent derailments or limit damage caused by derailments, by having rail on both sides of the wheel flange. Also found on curves with a tight radius and switches and crossings[30]
  • Gunzel (AU): Railway enthusiast. In Melbourne, Victoria it often refers to tramway enthusiasts.


Definitions Points of Interest
  • Hack (slang, US): A caboose, since it carried the crew around like a taxicab.
  • Hammerhead style (slang, US): The practice of running a Diesel locomotive with its long hood forward. This has been done for a variety of reasons, such as crew safety in case of a collision. On short runs, operating the locomotive "backwards" is more economical than using a wye or turntable or operating a second locomotive. Some locomotives may have a second control stand to facilitate operation in the "reverse" direction.
  • Handcar (US), A small, hand-powered railroad car used for track inspection. Pump trolley (UK).
  • Harmonic rock: 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 or HEP: A scheme whereby the locomotive engine or a separate generator provides 'hotel' power to carriages.[31]
  • Headboard: A sign attached to a locomotive to identify a named train or tour/charter, or for other special occasions.[32]
  • Headshunt (UK), Shunting neck (US): A length of track feeding a number of sidings that permits the sidings to be shunted without blocking the main line, or where two lines merge into one before ending with a buffer, to allow a run-round procedure to take place.[33]
  • 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".[34]
  • Heavy haul: Heavy freight operations.
  • Heavy rail (US): A city-based transit rail system that runs on its own dedicated track and often underground. Subways are considered heavy rail. Refers to commuter rail and inter-city rail when used by the FRA or in other countries.
  • Heavyweight (US): During the period between about 1910 and the mid nineteen thirties, most passenger cars in the US were built with three axle trucks, concrete floors, and riveted, double walled sides and often weighed 90 - 100 tons or more. Heavyweight construction was used to improve ride quality.[31][35]
  • Highball (US): 1. The conductor's signal for a train to depart. 2. To move at speed over the main track on a clear signal indication. Originated with the now-obsolete ball signal system, in which a ball hoisted all the way to the top of its post indicated to a train crew that the track ahead was clear.[31]
  • High cube (US): A boxcar whose vertical clearance is excessive (see Plate).
  • High Iron (slang): The mainline track.
  • High rail: The upper rail in a curve or superelevation which typically experiences the higher lateral loads and greater wear.
  • Hit the ground (slang): To derail.
  • Hogger (slang, US): A locomotive engineer.[31][36][37]
  • Hog law (slang, US): The federal law limiting a train crew's on-duty time to 12 hours, whereupon all service (except transportation to an off-duty point) must stop.
  • Hole, the: A passing siding. Inferior trains "lay over in the hole" to let superior ones pass.
  • Home signal: See absolute signal.
  • Hoodlebug (slang, US): A small commuter passenger train or trolley.
  • Hood unit (US): A locomotive whose sides and roof are nonstructural and do not extend the full width of the locomotive. Structural strength comes from the underframe.[31]
  • Horn blocks: Plates lining the axlebox cut-outs in a locomotive frame to allow smooth vertical movement under control of the springs.
  • Hotbox: An axle bearing that has become excessively hot due to friction.[31][38][39]
  • Hotbox detector: A device attached to the track which monitors passing trains for hot axles, and then reports the results via a radio transmission (US) or a circuit to the signal box (UK). (see defect detector).[31]
  • Hotel power (US): Electric power used to provide for the comfort of passengers aboard a train en route. See "HEP" above.
  • Hot rail (US): 1. Any section of track over which a train movement is imminent. The closer and/or faster the approaching train, the "hotter" the rail. 2. On some electrified railroads and rapid transit lines, the third rail which supplies power to locomotives or cars.
  • Hotshot (US): A fast, long-distance train given priority on the track over other trains.
  • Hudson: 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 (that is, humping the cars). This is faster and requires less effort than moving cars with a switching engine.[31]
  • Hunting: 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.[31]


Definitions Points of Interest
  • Independent brake: The common name for the braking system that applies or releases the brakes of a locomotive independently from its train; sometimes called the locomotive brake in layman's terms.
  • Infill station (sometimes in-fill station): A train station built on an existing passenger line to address demand in a location between existing stations.
  • Injector: A device to force water into a steam locomotive's boiler by steam pressure.[40]
  • Interchange: Any track or yard where rail cars are transferred from one carrier to another.
  • Interlocking (US): Any location that includes a switch or crossing of two tracks, derived from the early practice of installation of a system of mechanical equipment called an interlocking plant to prevent collisions. See also signal box. Interlocking is also the term for the actual mechanical or electrical apparatus that prevents switch/points and signals from being operated in ways that would allow for conflicting train movements.[40]
  • Intermodal freight: Moving goods by more than one type of vehicle. Intermodal freight can be transported using shipping containers which can easily be transferred among railroad flatcars, ships, airplanes, and tractor-trailer trucks.[40]
  • Intermodal passenger: Moving people by more than one type of vehicle.[40]
  • IRJ, IBJ: Insulated rail joint/insulated block joint. Rail joints incorporating insulation to isolate individual track circuits.
  • Island platform: A railway platform that has tracks along the full lengths of both sides.


Definitions Points of Interest
  • Jack: A dwarf signal (slang, Boston and Maine and New York New Haven and Hartford Railroads)
  • Jerk a lung (North America): To break a train in two, usually by shearing the knuckle pin in a coupler, often caused by the application of excessive head end power at startup. Example: "The engineer jerked a lung on the upgrade." Also: Get a knuckle.
  • Johnson Bar (locomotive) (US): On a locomotive, a long, heavy lever that operates the reversing gear, etymology unknown.[41]
  • Join the birds (slang, US): To jump from a train in the event of an emergency, e.g. an inevitable collision or boiler mishap.
  • Joint bar, fishplate (UK): Joins the ends of rails in jointed track. Also referred to in North America as a rail joiner or angle bar.[42]
  • 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 (UK) or joint bars (US).[41]
  • Journal bearing: a bearing without rolling-elements; a plain bearing
  • Journal box, the housing, or box, of a journal bearing.[43]
  • Jubilee: A steam locomotive with a 4-4-4 wheel arrangement.
  • Junction: A point at which two lines or separate routes diverge from each other.[41]


Definitions Points of Interest
  • KE: (Kinematic Envelope) 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.
  • 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.
  • Key (UK): Timber or sprung steel block used to secure Bullhead rail into the chairs.
  • 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 to make up or break down trains or classify large numbers of cars in an expedient fashion. Differs from a flying switch (see) 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.
  • Knock down (US): To pass an absolute signal and thereby change its aspect to stop; originated in the days of semaphore signals whose arms would drop to the stop aspect when passed.
  • 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.


Definitions Points of Interest
  • Lantern (US) Lamp (UK/AU): A portable (often handheld) light source that is used to signal train crews.
  • Lashup (US): Railfan parlance for a locomotive consist.
  • Lead track: A non-main track from which several others branch within a short distance, such as within a rail yard or engine terminal.
  • Leaner (US): (slang) A car in which the load has shifted, or it has been improperly loaded, or a mechanical failure has occurred that causes the car to lean to one side. This could potentially cause a collision or derailment.
  • Level crossing: a crossing on one level ("at-grade intersection") – without recourse to a bridge or tunnel – generally of a railway line by a road or path (also called a railroad crossing, railway crossing, train crossing or grade crossing (US)). The term is sometimes used for a crossing by (not a junction with) another rail track (known as a flat crossing in the UK).
  • Level junction (US), Flat junction (UK): A junction in which all track crossings take place at grade and routings must therefore be controlled by signals and interlocking.
  • Light engine: A locomotive travelling on its own, or perhaps with just a caboose (brake van) attached.[44]
  • Light rail: A city-based rail system based on tram 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.[45] Light rail vehicles (LRV) generally have a top speed of around 55 mph (89 km/h) though mostly operating at much lower speeds, more akin to road vehicles. 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.[44]
  • 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 by the Railroad Safety Appliance Act of 1893.
  • Local train: A train that stops at most, if not all, stations along its route. Often referred to in North America as a "milk train" or "milk run" (usage from the days when trains stopped at every station and stop along their route to pick up fresh milk brought to the stations daily from local dairy farms).
  • Location case (UK): A trackside cabinet used to house signalling equipment such as relays or transformers.
  • Loop (UK), siding (US): Used on single-track railway lines, a loop is a second parallel track (running for a short distance), allowing two trains to pass by one another.
  • Lunar, as in lunar white, is a color of Railway signal light. It is an off-white color, achieved by the use of a clear lens of very light blue, to make it distinct from a light that has a broken lens. In UK practice, it is the color used for the type of junction indicator known as a feather, so-called for its resemblance to a popular inn sign.


Definitions Points of Interest
  • Main generator: In a diesel-electric locomotive, the main generator is coupled directly to the prime mover and its sole purpose is to feed electrical energy to the traction motors (an auxiliary generator powers lights and electrical appliances in the cab).
  • Mainline (US) or Main line (UK): The principal artery of a railway system; cannot be occupied without authorization in the form of a movement permit (e.g. track warrant) or signal indication.[46]
  • Main reservoir: The compressed-air tank of a locomotive containing source air for the brakes and other pneumatic appliances.
  • Main rod (US): The drive rod connecting the crosshead to a driving-wheel or axle in a steam locomotive.[18] Connecting rod (UK).
  • Maintenance of way (US): The maintenance of railroad rights of way, including track. Often abbreviated to MOW (as in MOW car).[46]
  • Mallet (pronounced "mallay"): type of articulated locomotive designed by Anatole Mallet. See "Compound Engine" above.[46]
  • Manifest: An express freight train carrying a variety of general merchandise.
  • Matchbox tank (UK slang): a type of pannier tank where the tanks are square and do not rest of the locomotive frame.
  • Mating worms (US): Penn Central logo (jargon/slang).[47][48]
  • Mechanical semaphore signal: A signal in which the aspect is conveyed by moving an arm.
  • Merry-go-round (MGR) train (UK): coal train running between a coal mine and a power station, loading and unloading without stopping or shunting.
  • Mikado: A steam locomotive with a 2-8-2 wheel arrangement.
  • Milk Train: A aggregator for transporting milk from farms to dairies, such as British Railways Milk Trains
  • MLW: Montreal Locomotive Works, bought by Bombardier and closed.[46]
  • Mogul: A steam locomotive with a 2-6-0 wheel arrangement.[49]
  • Motion (UK): Collective term for the connecting rod, coupling rods and valve gear; forms part of the running gear. Originally from Watt's invention of the parallel motion.[50]
  • Motor train (UK): See Auto train (UK) above.
  • Mountain: A steam locomotive with a 4-8-2 wheel arrangement.
  • Mud ring: The bottom of the water space surrounding a steam locomotive's firebox; collects solid deposits distilled from the water supply during the boiling process.
  • Multiple aspect signalling: A system of colour-light signalling in which signals may show 3 or 4 aspects.
  • Multiple unit (UK) MU (US): 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 (DEMU) and Electric Multiple Unit (EMU) are more common terms. These may also be termed railcars.
  • Multiple-unit train control (US), Multiple working (UK): generally seen as the abbreviation MU, this normally refers to the ability of diesel and electric locomotives or multiple units to be joined together and controlled from one driving station. Such a set of joined locomotives is called (US) a consist or (colloquially) "lash-up" and is said to be "MUed together".[46]
  • Multiple working (UK): see Multiple unit (above).


Definitions Points of Interest
  • Narrow gauge: Railroad track where the rails are spaced less than apart.[51] There are many common gauges narrower than standard, amongst them widely in Africa and Asia; , which was the most common narrow gauge in the U.S.; , used in various locations across Europe, Asia and elsewhwere, South America and Australia, and , which saw widespread use in the UK. Meter gauge is also widely used in Asia and Africa. Narrow-gauge lines are often found in mountainous terrain where the cost savings of building a smaller railroad can be considerable. (Historically, the term "narrow gauge" was once used in Britain for what is now called standard gauge, as the only other gauge then in common use was the Great Western Railway's broad gauge.)
  • NIMBY (slang, US, abbr. "Not in My Back Yard"): Railroaders' derisive nickname for residents who are opposed to trains running through their neighbourhoods.
  • Northern: A steam locomotive with a 4-8-4 wheel arrangement. Also known variously in North America as "Pocono", "Niagara", "Confederation", "Greenbrier", "Potomac" et al. (see Whyte notation).
  • Notch 8: The 8th Notch of the throttle control, indicating Full Power.


Definitions Points of Interest
  • One-man operation (US), (OMO). Operation of a train by the driver or motorman alone, without a conductor.
  • Open wagon (UIC, UK), Gondola (US). A form of freight hauling car for bulk goods.[52]
  • ORER Official Railway Equipment Register.[53]
  • Out to foul: When equipment is placed ahead of the fouling point of a switch turnout.
  • Outlaw (US): To cease operation of a train at the federal time limit of 12 hours. Other slang terms include "can", "die", or "tank".
  • Overbridge (UK): A bridge over the railway.
  • Overlap (UK): A distance (normally 180 metres or set according to the permitted speed of the line) beyond a stop signal which must be clear before the preceding stop signal can display a proceed aspect; allows a margin in case a train overshoots a signal before stopping.


Definitions Points of Interest
  • P-train: An NMBS/SNCB commuter train.
  • Pacific: A steam locomotive with a 4-6-2 wheel arrangement.
  • Pannier tank: A tank locomotive with the water tanks mounted on the boiler like panniers.
  • Pantograph: An arm to pick up current from overhead lines.[54]
  • Paper: Colloquially, a track warrant, train order or other movement permit that is dictated by a dispatcher and copied in writing by a train crew member.
  • Pennsy: 1. Abbreviation for the former Pennsylvania Railroad. 2. A nickname for the PRR's K-4 class steam locomotive.
  • Per diem: A fee paid by a rail company to the owner of a car (US) (wagon (UK)) for the time it spends on the company's property; also an authorized living expense payment for some workers forced away from their home terminal. Pronounced by some U.S. railroaders per die-um, not per dee-um.[54]
  • 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.
  • PICOP (UK): Person in Charge Of Possession – the railway or contractor's official responsible for safe working during engineer's possession.
  • Pig train (slang, US): An intermodal train, so nicknamed after its "piggyback" hauling of trailers and containers on flat cars.
  • Pilot: 1. A deflective shield affixed to the front of a locomotive to protect its wheels from on-track debris; archaically called a "cowcatcher." 2. An employee qualified on the operating rules and physical characteristics of a certain section of the railroad, assisting a crew who is not so qualified.
  • Pilot engine (UK), Helper (US): The leading locomotive during a double heading operation, attached in front of the train engine (road engine).
  • Piston: The moving component in the cylinder of a steam engine or internal combustion engine that translates into motion the force exerted by pressurised steam or exploding fuel.[55]
  • 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.
  • Plate (US): The measurement of a freight car's vertical clearance; Plate F and above is considered excess height, and such cars must avoid low-clearance routes.
  • Point machine (UK): A motor or device which operates points.
  • Points (UK): switch (US). Also "turnout". (Also in the US, "points" refers to the articulating rails that determine the route to be taken.)
  • Pony truck: A two-wheel truck (US) or bogie (UK) at the front of a locomotive.[56]
  • Porch: Usually on U.S. locomotives, it is the extended walkway at either end of a locomotive. Can either be long or short, depending on the buyer's specifications.
  • Porter: A Porter had various roles: A Baggage Porter assisted with luggage; an Operating Porter assisted with Safeworking duties; a Station Porter assisted with general station duties and a Lad Porter was 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.[57][58]
  • Position light signal: A block signal in which the position of the lights determine the meaning of the aspect shown.
  • Positive train control (PTC): A system of functional requirements for monitoring and controlling train movements to provide increased safety
  • Pound (rail): Term describing 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 slang term referring to a locomotive or group of connected (MU'd) locomotives serving as the motive power for a train (as in "the hostler brought the power to the service pit.")[54]
  • Power braking: Pulling against the train brakes at the higher end of the locomotive's power output (e.g. notches 5 through 8 on a conventional throttle); this is considered wasteful of fuel and brake shoes, and is therefore discouraged by most operating departments.
  • Prairie: A steam locomotive with a 2-6-2 wheel arrangement.
  • Prime mover: The internal combustion engine of a diesel locomotive.
  • Pull-apart: A rail broken from cold-related contraction.
  • Push pole: Push pole about 12 feet (366 cm) long and having a diameter of 5 inches (127 mm). They were placed in receptacles called push pole pockets. The pole was placed between the locomotive and the freight car, and used to push the car on or off a siding or to another track. Used between 1870 and the mid-1960s.[59]
  • Push-pull: A mode of operation whereby a locomotive-hauled train may be driven with the locomotive at the front, middle or back of the train. Also: Auto train (UK), above. See Top and tail for train with locomotives at both front and back.[54]

(US) Also referred to as DPU, or Dispersed power unit, it is designed to even out power or weight put on one locomotive. Usually this is used in steep grades for the uneven weight and braking. With DPU's, it allows braking at both ends and power.[dubious ]


Definitions Points of Interest
  • Q-inspection (US): Also quarterly or periodic inspection, a federally-mandated safety inspection performed on a locomotive every 92 operating days.
  • Quiet Zone (US): A designation by the Federal Railroad Administration that removes the requirement for train operators to sound their horn when approaching each public crossing in a certain area, often near residential neighborhoods who have asked for the status. Because the train does not sound its horn while approaching the crossings, safety upgrades to all of the crossings must be made in order to compensate. These upgrades usually include double gates, additional signage, lights, and bells, if they are not already present. Additionally, the residents requesting the status must indemnify the railroad from any resulting crossing mishaps.


Definitions Points of Interest
  • Railbus: A passenger rail vehicle (typically non-articulated or rigid frame) that was derived from bus propulsion and construction technology, but which may evolve into larger dimensions, performance and characteristics similar in appearance to a light DMU Railcar
  • Railcar: 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.
  • Railfan: A hobbyist or enthusiast of trains (q.v. "Foamer").
  • Rail grinder: a machine used to remove irregularities in the surface of the rails. May be self powered or part of a consist.
  • Rail profile The cross section shape of rail. There are many rail profiles which are often specific to individual railroads. Rails need to 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.
  • Railroad car: A railroad vehicle that is not a locomotive.
  • Railroadiana: Artefacts of railways around the world.
  • Rail sled (US): A form of wheel chock that slips onto the rail under the wheel of rolling stock which prevents the vehicle from rolling.
  • Rail Tractor: A small petrol (gas) or diesel shunting (switcher) locomotive.
  • Railway line may refer to:
    • 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 which has been given the line name officially (e.g. by ELRs in the UK).
    • A set of railway routes which are bundled for publicity purposes by, e.g., a UK TOC.
    • A set of railway routes without official standing, on which railfans have bestowed a title.
  • Railway station : A train station, a stopping point for trains, usually with passenger access.
  • Rake: (UK) A group of passenger coaches coupled together.
  • 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.
  • Refuge siding: 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.
  • Rent-a-Wreck (slang, U.S.): A (usually old) locomotive owned by a leasing company.[60]
  • Reporting mark: 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.[61]
  • Rerail frog or rerailer 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.
  • Restricted speed (US): A speed not exceeding 20 mph which allows stopping within half the range of vision short of an obstruction on the tracks.
  • Retarder: A device installed in a classification yard used to reduce the speed of freight cars as they are sorted into trains.[62]
  • Reverser or Reverser handle: the handle that controls the directional control on a locomotive (see also Cut off, above).
  • RFE (US): abbr. Road Foreman of Engines.
  • Ribbon Rail: Continuously welded rail.[61]
  • Right-side failure: A failure in a signalling or other safety critical system which leaves the system in a safe condition.
  • RoadRailer: A highway trailer, or semi-trailer, that is specially equipped for direct use on a railroad.
  • Roll-by: (US; also "Rollby") Visual inspection of a passing train by personnel on the ground for defects or dragging equipment.
  • Rolling stock: (UK) A railway vehicle that is not a locomotive; 'railway car'. (US) Any railroad car and/or locomotive.[61]
  • Rookie: See Trainee.
  • Rotary: Short for rotary snowplow, an extreme-duty railroad snowplow used mainly in the mountain ranges of the American West.
  • Roundhouse: A circular or semi-circular structure used for storage and running maintenance of locomotives.
  • Rule G (US): The universal rule prohibiting the use of drugs and alcohol.
  • Ruling grade: The longest and/or steepest grade on a division; sets the standard for track speeds, locomotive tonnage ratings, and train handling instructions.
  • 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 (runaround (US)): 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).
    (See headshunt for diagram of a 'run-round loop'.)[61]
  • 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.


Definitions Points of Interest
  • Saddle tank: A tank locomotive with the water tank mounted on top of the boiler like a saddle.[63]
  • Safety Appliance Act (US): A law mandating air brakes, grab bars, and automatic couplers
  • Safeworking: The system of rules and equipment designed to ensure the safe operation of trains.
  • Sand: granular material poured on the rail in front of the drive wheels to improve traction. (Sandite is a more specialised form for a similar purpose.)
  • Sandbox: A container on locomotives and self-propelled multiple units, or trams, that run on tramways and adhesion railways. The container holds sand which can be dropped on to the rail to improve rail adhesion under wet, steep or slippery rail conditions. The sandbox and operating mechanism are collectively known as 'sanding gear'.
  • Sandite: consists of a mixture of sand, aluminium and a unique type of adhesive, used instead of plain sand for extreme slippery rail conditions.
  • Santa Fe type: A steam locomotive with a 2-10-2 wheel arrangement, named for the Atchison, Topeka and Santa Fe Railway, the first railroad to use such a configuration.
  • Saturated locomotive: A steam locomotive not equipped with a superheater (see); 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 over sized loads; the car is loaded in such a way that the load forms part of the car superstructure.
  • Searchlight: A signal with a single light source usually capable of displaying three different colors. An internal mechanism governs the color displayed.[63]
  • Section: The division of the track for security (occupation).
  • Semaphore: A type of signal that has a moving arm; any signalling using semaphores.
  • Shay: A type of geared steam locomotive built to the patents of Ephraim Shay.[63]
  • Shoofly (US): A temporary stretch of track that takes trains around construction or an accident scene.[63]
  • Shunt (UK) (AUS): To move trains or vehicles from one track to another.
  • Shunt (US): To bond the rails/power feeds between sections on trolley/light rail systems, so as to temporarily bridge past dead areas.
  • Shunter (UK): switcher (US) or shifter (PRR only): A small locomotive used for assembling trains and moving railroad cars around. Also, a person involved in such work.[63]
  • 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 tank locomotive 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 will often meet up with loading docks at rail car height in the building. In the U.S. the term is also used to cover the British term: loop. Also, a passing track in the U.S.
  • Signal: A device that indicates to the driver of a train information about the line ahead.
  • Signal aspect: The information conveyed to a railroad vehicle operator by a block signal. Signals may use colored lights, position-significant lights or mechanical semaphores to generate various aspects.
  • Signal box: A building or room which houses signal levers (usually in a frame), a control panel or a VDU-based control system.
  • Signal Passed at Danger or SPAD (UK): where a train disobeys a stop signal.
  • Signalman: A person in charge of the signalling at a station or junction, often in a Signal-box.
  • Six-foot: The narrow corridor between a pair of closely spaced tracks, nominally six feet wide. See also four-foot and ten-foot.
  • Six-pack (slang, US): A six-axle diesel locomotive.
  • Slack (UK): A temporary speed restriction to protect, for example, sections of track in poor condition and awaiting repair. Also applies to the timing tolerance included in timetable schedules to allow for such restrictions.
  • Slack action (UK/US): Looseness in a train caused by mating clearances in couplers.[63]
  • Sleeper (UK), tie (US): Bars placed at 90° to the rail tracks to support the rails. Generally of wood, concrete or steel, with hardware to affix the rails, usually spikes, nails or bolts. Note in the UK baseplates and clips are used to affix the rail to the sleeper. Spikes are widely used in North America.
  • Slip coach (UK): A passenger coach that is disconnected from a train without the train havin to stop. While the train continued on its route, the slip coach would be guided and stopped by a guard on board using the coach's own brake mechanism. This practice was almost entirely limited to the United Kingdom and was discontinued in the 1960s.[64]
  • Slippery rail: 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 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.[63]
  • 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/chimney; steam pipes to and from the cylinders pass through here; contains the blastpipe/exhaust nozzle 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. A smokebox door allows access for cleaning.
  • Smokestack (abbr. stack) (US): chimney (UK).[65]
  • Snow plough (Snowplow) or rail snow plough is a rail service vehicle used for snow removal from train tracks.[66][67]
  • Snow shed: A long shelter erected over a railroad track on the side of a mountain to protect the line from avalanches.
  • SPAD (UK): Signal Passed at Danger, where a train disobeys a stop signal. Sometimes referred to as a "blown red" in U.S. railroad slang.
  • Span bolster: the beam between two bogies
  • Speeder (US): A small vehicle used to let track inspectors and work crews move quickly to and from work sites. (Obsolete) Speeders have mostly been replaced by trucks and SUVs with retractable flanged wheels.[68]
  • Spike: A bolt, pin or nail used to hold rails, or plates connected to the rails (known as tie plates), to sleepers (ties). Commonly called a "Dog" or "Dogspike" in Australia.
  • Spiral easement See Track transition curve. Also known as tangent lead-in.[63]
  • Spreader a maintenance of way equipment designed to spread or shape ballast profiles, remove snow, clean and dig ditches as well as trim embankments
  • SPT (UK): Signal-post telephone - A direct no-dial telephone link to the relevant Signal-box, positioned on or near a signal.
  • Spur (US): A stretch of rail that branches off the main line. Different from a siding or stub, spurs can be miles in length, and usually have only one destination at the end.[63]
  • SPURT (India): An acronym for Self Propelled Ultrasonic Rail Testing, a self-propelled rail defect detector car.[69]
  • Staff and ticket: A method of safeworking involving a token.[63]
  • Standard gauge: Railroad track where the rails are spaced apart. This is by far the most common gauge of railway worldwide.[63]
  • Station master: The person in charge of a station.
  • Station pilot (UK): Shunting engine based at a major passenger station and used for passenger train shunting duties.
  • 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.[63]
  • Steam reverser: A reversing gear worked by a steam piston controlled from the cab.
  • Steeplecab (US): An electric locomotive with a central cab and sloping "noses" on each end.
  • Steward: A person in a dining car with a role similar to that of a Maitre d’Hotel.
  • Stretch braking: Pulling against train brakes at the lower end of a locomotive's power output, e.g. notches 1 through 4 of a conventional throttle, thus keeping coupler slack stretched and permitting smoother train handling. This is considered most effective on undulating track profiles or when dynamic braking is not available.
  • Stub (North America) A relatively short section of track that ends at a bumper or wheelstop, most often found in a terminal. Not to be confused with a spur, which may be miles (kilometers) in length.
  • Subway (UK): A tunnel passing underneath the railway tracks to allow passengers to cross from one platform to another.
  • Subway (US): A railroad that runs underground, generally in a large city. Subways are also considered "heavy rail" because they operate on their own dedicated track. Not to be confused with the interurban definition of subway, which is normally a light-rail passenger service running mostly underground.
  • Supercharger 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 (UK): Synonymous with cant: the banking of railroad track on curves. Specifically, the practice on high speed lines (where the cant needs to be higher) of gently introducing the elevation of the outer rail before the bend starts, in order to avoid sudden lurches.[63]
  • Superheater: A device in a steam locomotive that raises the temperature of saturated steam substantially beyond the boiling point of water, increasing power and efficiency.[63]
  • 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.
  • Switch (US): points (UK). Also "turnout".[63]
  • Switcher (US), shunter (UK): A small locomotive used for assembling trains and moving railroad cars around.[63]
  • Switchman: A railroad worker responsible for assembling trains and switching railroad cars in a yard; now often used together with brakeman as a single job description ("brakeman/switchman").


Definitions Points of Interest
  • Tank car: A type of rolling stock designed to transport liquid and gaseous commodities.
  • Tank engine (UK): A locomotive that carries its own fuel and water instead of hauling a tender. The fuel is usually in a bunker behind the cab and the water in tanks on either side of, above, or below the boiler (respectively: side tank, saddle tank, well tank).
  • Team track: A spur or siding for loading freight, often used by firms not having their own direct rail access.[70]
  • Tender: A specialized rail car attached to a steam locomotive to carry its fuel and water supplies, along with tools and flagging equipment.
  • Ten-foot: An area, usually at least ten feet wide, between a pair of widely spaced tracks, wide enough to form a place of safety in which railway workers can stand while a train goes past. See also four-foot and six-foot.
  • Ten-wheeler (US): A steam locomotive with a 4-6-0 wheel arrangement.
  • Terminal station (esp. U.S.), terminus (esp. UK): A station sited where a railway line or service ends or terminates.
  • Terminal railroad (or terminal railway) is 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.[71]
  • Texas type: A steam locomotive with a 2-10-4 wheel arrangement.
  • The T (US): A nickname for Massachusetts Bay Transportation Authority (MBTA), the Subway service through Boston, Massachusetts.
  • Theatre indicator (UK) An illuminated number usually attached to signal indicating arrival platform for train approaching a station.
  • Third rail: An electrified rail that runs along the tracks, giving power to trains. Used mostly in subways and rapid transit systems.[70]
  • 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.[64]
  • 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.
  • Through-routing: Combining two or more different railways onto a common length of track. This is often done to eliminate redundant trackage and/or improve service.
  • Tie (US): sleeper (UK): A rectangular object used as a base for railroad tracks.[70]
  • Tie plate: A plate which is bolted to sleepers, holding the rails in place.
  • Timetable direction: The general compass direction of a railroad or subdivision, as specified by its official timetable (rulebook). Only the four cardinal compass points may be used to state a train's direction of travel.
  • TOFC: An abbreviation for "Trailer-On-Flat-Car" (Intermodal freight transport).[70]
  • Token: A physical object given to a locomotive driver to authorize him to use a particular stretch of single track.
  • Top and tail (UK): A train with locomotives at both ends, for ease of changing direction.
  • Torpedo (US): A small explosive device strapped to the top of the rail to alert an approaching train of danger ahead. A torpedo creates a loud noise upon contact with a locomotive wheel, signaling the engineer to reduce speed to 20 mph or less; the train cannot resume its original speed until it has traveled at least a mile beyond where it encountered the device. Traditionally used in pairs to ensure that the sound registered with train crews, torpedoes today are essentially obsolete as modern locomotive cabs' soundproof construction renders the devices useless. (UK:Detonator)[70]
  • Torpedo tube: A slang term for a type of roof-mounted air reservoir. The long, cylindrical tanks (which resembled the torpedo launch tubes on World War II PT boats) were integral to the design of the EMD SD24, and retrofitted (both at the factory and on an aftermarket basis) to other locomotives such as the GP7, GP9, and CF7 (typically when the units were placed into passenger train service and larger fuel and water storage tanks were required).
  • Trackage rights (US): The legal right of one railroad company to use the tracks of another, as agreed to by the companies concerned or their predecessors; may also be ordered by government regulators, for example, as a condition of a merger. Running powers (UK).[70]
  • Track bed or trackbed: the foundation of rail tracks
  • Track circuit: An electrical circuit that detects the presence or absence of locomotives and/or cars in a section of track, the section referred to as a block. Track circuits provide real-time inputs to signaling logic.
  • Trackside objects: See Wayobjects under "W" below.
  • Track bulletin: A form used by railroad employees that shows the locations of slow orders, maintenance of way work locations, and other conditions affecting the track and movement of trains.
  • Track tamping machine: Generally, a locomotive used in track maintenance and equipped with track lifting facilities, and paddles enabling ballast to be pushed beneath a rail track so as to assure its level and cant.
  • 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 (TWC) (US) Occupancy Control System (OCS) (CA): A system for authorizing main track occupancy using defined points such as mileposts, switches, or stations.[70]
  • Traction motor: A large electric motor that powers the driving wheels of an electric or Diesel-electric locomotive.[70]
  • Traction supply: The supply for the driving traction motors of electric trains.
  • Tractive effort: the pulling or pushing force exerted by a locomotive or other vehicle.
  • Trailing: A turnout is trailing if the two legs of that turnout merge in the direction of travel. See Facing.
  • Trainee: An employee who is new on the job and has completed railroad school.
  • Train engine (UK), Road engine (US): The locomotive closest to the train during a double-heading operation.
  • Trainman: An employee assigned to train service, such as a Conductor, Brakeman or Switchman.
  • Trainmaster: A Dispatcher, the person(s) in charge of all traffic within the assigned blocks.
  • Train order: (US), A system for authorizing main track occupancy using telephone, telegraph and wayside stations to pass authority to train crews.
  • Train register (UK): A book or loose-leaf sheets kept in a signal box and used to record the passage of trains, messages passed, and other prescribed events.
  • Trainset: A group of rolling stock 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 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 are trams that are designed to run both on the tracks of a city-based rail system and on the existing railway networks. Tram-trains dual-voltage capability makes it possible to operate at lower speeds on city streets and at over 60 mph (100 km/h) on main line tracks allowing travel in an extended geographical area without changing the method of transport.
  • Treadle: A mechanical or electrical device for detecting the presence of a rail vehicle with pin-point accuracy, unlike a track circuit, which provides detection over an arbitrary distances.
  • Triangle (UK), Wye (US): A track layout that facilitates the turning of engines or complete trains.
  • Truck (mainly US and Canada as well as Mexico) See Bogie
  • Truck (UK, outdated/informal): freight car.
  • Turnout: A switch (also known as a set of points)
  • Turntable: A section of track that can rotate, allowing locomotives and rolling stock to be reversed, and also allow a large number of engine maintenance sidings to be accessed in a small area.


Definitions Points of Interest
  • U-boat (slang, US): A nickname for General Electric's Universal series of diesel locomotives (U25B, U30C, etc.) Not to be confused with early 20th-century German submarines.
  • Underbridge (UK): A bridge carrying the railway and allowing a roadway (etc.) to pass under the railway.
  • Union station or union terminal (US), joint station (UK): A railway station (q.v.) at which tracks and facilities are shared by two or more railway companies.[72]
  • Unit train: A train whose cars all carry the same commodity, such as grain or oil.
  • Up (UK, etc.): A direction (usually towards London, other capital city, or the headquarters of the railway concerned) or side (on left-running railways, the left side when facing in the up direction). The opposite of down. The up direction is usually associated with even-numbered trains and signals.
  • UP (US): The common name and reporting mark for the Union Pacific Railroad.


Definitions Points of Interest
  • Vacuum brake A continuous train brake which is fail-safe in operation: the brake is powered by a vacuum 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 linkage between a steam locomotive's pistons, steam valves, and driving rods, transmitting the steam's power to the drive wheels.
  • (goods) Van (UK), boxcar (US): An enclosed railroad car, or piece of rolling stock, used to transport freight.
  • Van (CA): Eastern Canadian word for caboose.


Definitions Points of Interest
  • Wayside: Trackside. The term presumably has its origin from the term right-of-way.
  • Well tank: A type of tank locomotive. The water tank is mounted between the frame plates, beneath the cab and boiler.
  • Well wagon (UIC): A flat wagon that has a depressed centre and is used for carrying extra tall loads.
  • Wheel: The rolling component typically pressed onto an axle and mounted on a rail car or locomotive truck or bogie. Wheels are cast or forged (wrought) and are heat treated to have a specific hardness. New wheels are trued to a specific profile before being pressed onto an axle. All wheel profiles need to be periodically monitored to insure proper wheel to rail interface. Improperly trued wheels increase rolling resistance, reduce energy efficiency and may create unsafe operation. A railroad wheel typically consists of two main parts: the wheel itself, and the tire around the outside. A rail tire is itself steel, and is typically heated and pressed onto the wheel, where it remains firmly as it shrinks and cools.
  • Wheel Climb: The process of a wheel climbing up and often off the inside or gauge side of the rail. It is a major source of derailments. Wheel climb is more likely to occur in curves with wheels whose flanges are worn or have improper angles. See Rail adhesion.
  • Wheel Flange: The inner section of a wheel that rides between the two rails. The angle between the wheel tread and flange is often specific to the rail to prevent wheel climb and possible derailments. See Rail adhesion. The wheel flange is part of the wheel tire.
  • Wheel slip: The loss of traction due to a slippery rail or wheel. Wheel slip was common with steam engines as they started to move due to the excessive torque often generated at low speed. Steam engines carried sand dispensing gear to increase traction at the start of motion.[73]
  • Wheel Tapper: An historical railway occupation; people employed to tap train wheels with hammers and listen to the sound made to determine the integrity of the wheel; cracked wheels, like cracked bells, do not sound the same as their intact counterparts. The job was associated with the steam age, but they still operate in some eastern European countries. Modern planned maintenance procedures have mostly obviated the need for the wheel-tapper.
  • Wheel Tread: The slightly conical section (often with a 1 in 20 slope) of a railroad wheel that is the primary contact point with the rail. See Rail adhesion.
  • Whistle: Train whistles are used as a safety warning and also by the engineer to communicate to other railroad workers. See train whistle for a description of the whistle code used to communicate. Also a nickname for an air horn on a diesel locomotive. Steam engine whistles were historically known as chimes in the US during the 19th century.
  • Whistle post: An advanced warning to the engineer of an upcoming grade crossing. It is the point at which the engineer should begin sounding the whistle or horn.
  • Whyte notation: A system of describing steam locomotive wheel arrangements, e.g. 4-6-4, 2-10-2. The first number indicates the number of "pilot" wheels that help lead the engine into turns. The second is the number of coupled wheels ("drivers"). Third are the trailing idler wheels, usually to provide support to larger fireboxes. Articulated locomotives are similarly described. For example, a Union Pacific "Big Boy" would be described as a 4-8-8-4, wherein the pilot has four wheels, followed by two sets of drivers, 8 wheels per set, and a 4 wheel trailing bogie under the firebox. The numbers include the wheels on both sides of the engine, so a 2-8-2 engine would have one idler, four drivers, and a final idler on each side of the engine.
  • Wigwag: A largely superseded Level or Grade Crossing Warning Signal consisting of a swinging disc facing road traffic with a red light in the centre. The disc normally hangs straight down, but an approaching train will set it swinging from side to side, the red light will illuminate or flash, and a bell will ring.
  • Working water: Also "foaming" or "priming"; the condition of a steam locomotive drawing water through its throttle valve, cylinders, and smokestack, often causing damage to the cylinders or running gear.
  • Wrong-side failure: A failure in a signalling system that leaves the system in a dangerous condition.
  • Wye (US), triangle (UK): Three railroad tracks in a triangular form with switches at all three corners. With sufficient lengths of track leading away in all three directions, a wye can turn a train of any length.[73]


Definitions Points of Interest
  • X-ing (AU): Slang for road crossing or level crossing. Crossing (US).


Definitions Points of Interest
  • Yard: A location where rolling stock is switched to and from trains, freight is loaded or unloaded, and consist made up. Also freight yard; classification yard or hump yard (types of freight yards); and coach yard (for passenger cars).[74]
  • Yard goat (slang, US): A yard switcher engine.
  • Yardmaster: The person(s) responsible for conducting all traffic within the yard. The Yardmaster gives orders for which cars go where in order to assemble or disassemble a consist.
  • Yellow: A colour associated with a warning or a need to slow down when used by flags or signals; the exact meaning varies from railway system to railway.
  • Yellowstone: A steam locomotive with a 2-8-8-4 wheel arrangement.


Definitions Points of Interest
  • Zig zag, (U.S. commonly) switchback: a way of climbing hills, where the train reverses direction for a while, and then reverses again to continue its journey.

See also


Further reading

  • Canadian National Railways: Linguistic Services. Freight Car Inspection & Maintenance: English-French Vocabulary = Surveillance et entretien des wagons: vocabulaire anglais-français. Montréal: Canadian National Railways, 1973. Without ISBN or SBN

External links

  • British Railways compared to American Railroads
  • Railway Industrial Clearance Association
  • Australian Railway Slangnl:Spoorwegjargon
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