Glossary
"
The irreverent term for a complicated control panel.
The "V" shaped brackets on the vehicle under frame used to suspend brake linkages.
The "W" shaped plate connected to the solebar of a wagon in which the axleboxes are suspended.
#
9.5 mm gauge, 2 mm to the ft, 1:152.4 scale.
A
This describes a system of train working whereby only one train is allowed to occupy one stretch of line at any one time. All passenger lines are worked on this principle.
a
A
In DCC: A decoder that is not intended to be installed in a locomotive, but remains in a fixed location and controls accessories such as signals or track switches/turnouts. Also known as &...
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In DCC: The address is the identification number used by the decoder to identify which communication it must act on. The address is usually unique for each decoder, but this is not a requiremen...
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a
proportion of locomotive weight borne by driving wheels.
A
Operating and controlling several locomotives as if they were a single entity by sending speed and direction commands to a common address. Also called decoder assisted consisting. See als...
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Meter which measures current flow in amperes.
The unit of electrical current, generally written as amps.
Conventional track voltage (NMRA Standard S-9) typically varying between zero and tweleve volts for speed control and polarity reversal for direction control.
Voltages and/or frquencies which convey information and are not digital.
a
structure carrying water over depressed ground.
wire-wound rotating bobbin core of electic motors used in models.
wheeled container running on narrow rails between and beneath normal rails for removal of locomotive clinker and ash.
A
More usually this term is used in conjunction with colour light signals. It refers to the indication given by the signal, a red "aspect" for instance, instructs the driver to stop.&nb...
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The brilliant but, fatally flawed railway propulsion idea pioneered by Brunel. Trains were connected to a sliding piston within a pipe which was laid along the centre of the track and propelled...
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Abbreviation for Association of Train Operating Companies. Body formed to represent the post - privatisation train operating companies.
Control circuits which sense opposite polarities at rail gaps and automatically reverse the polarity of the rails to allow smooth continuation of the motive power. Applications include: reversi...
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Operation of trains through relay banks, etc, without human.
Abbreviation for Automatic Warning System. A system incorporating electromechanical devices set between the rails which give audible and visual confirmation of signal aspects to a driver in his...
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A box in which the axle end is located so as to act as a bearing. These were packed with grease for lubrication. Modern axles now have roller bearings.
B
British Railways (1948 - 64), British Rail (1964 - 94). The nationalised UK railway system. Under this, all railways were subject to the central control of the British Railways Board, alt...
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Some locomotive decoders can sense the rotational speed of the motor and automatically adjust future digital pulses to the motor to maintain a desired speed. Also called load - compensating dec...
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b
chippings spread between and around sleepers.
B
The amount of information that can be transmitted between the command station and decoder(s) in a certain amount of time.
This is a mechanical disc signal used to repeat the setting of the signal ahead. They are used when signals are sited in awkward locations, say beyond an overbridge. They are mostly of th...
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Operating and controlling several locomotives as if they were a single entity by sending discrete speed and direction commands to each locomotive in the consist. See also "Consist".
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The name given to "The Reshaping of British Railways" report of 1963. This report heralded the famous railway line closure programme of the mid 1960s.
type of flat-topped firebox on locomotive.
The electrical waveform of digital packets transmitted along the rails is known as a bi-polar signal. Positive pulses followed by mirror image negative pulses are the key characterisation.
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A relay (qv) which will hold in either of two positions.
Colloquial term describing the four big railway companies set up at the grouping in 1923, i.e., LMSR, LNER, GWR, and SR.
A logical value that can be either a one or a zero.
A device, generally electronic (qv) whose function is understood even though its operation remains a mystery.
This describes the "AREA" controlled by a signal box, (sometimes called a block post). It refers to the distance between the previous signalbox's advanced starter signal and the first...
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b
train made up of identical wagons or vans etc.
B
diesel or electric locomotive having two driven axles, i.e. four driving wheels, on each of two bogies.
Colloquial term often used by railwaymen to describe the arm of a semaphore signal. The "board is off" means that the signal is raised or lowered to the line clear position.
b
a swivelling assembly carrying usually four wheels (sometimes six) mounted below a locomotive or coach.
principal cross-member of a bogie carrying the pivot.
B
A link in a circuit; often a wire linking two parts to ensure electrical continuity.
Barry Railway. Based in South Glamorgan. This was a small but highly profitable concern also carrying minerals.
Based in South Glamorgan. This was a small but highly profitable concern also carrying minerals.
A single support post fitted with two or more individual signals. Junction signal are more often bracket signals
The independently published "all line" railway timetable. First published in the 19th Century.
A metal lever used mainly on wagons to operate the vehicle's brakes manually whilst stationary in sidings.
The vertical support for a guard's handbrake wheel in brake vans.
Short for rail break (qv).
b
usually the last vehicle in a train from which the guard (conductor) can operate the train's brakes if neccessary.
B
A rectifier consisting of four diode elements connected in a square (bridge) formation to provide a reasonably level dc output. see rectifier .
Colloquial term often used by railwaymen to describe the arm of a semaphore sognal. The "board is off" means that the signal is raised or lowered to the line clear position.
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A specially encoded digital packet that will be acted upon by all decoders that receive the packet. Commonly used in service mode programming and for stopping a locomotive in front of a red sig...
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Shockabsorbing device of which two are normally fitted to the ends of rail vehicles. Designed to absorb impact and keep adjacent vehicles from damaging each other.
Lower outer crossmember of a railway vehicle underframe onto which buffers, coupling hooks, brake hoses and cables are fixed. Often, the headstock forms this part of the vehicle.
Frame or fabrication placed at the end of a line to stop vehicles from running off the track.
b
strongly sprung shock-absorbing fittings at each end of all railway vehicles.
coal receptacle at rear of tank locomotive.
B
A set of wires that serves as a conduit for electrical signals and distributes them around the layout.
A colloquial expression originating in the 1980s which describes the provision of buses to replace train services and allow rail closures.
C
A device used by model railroad engineers (operators) to control motive power and accessories by sending electrical or electronic instructions to the locomotive (via the DCC command station).
The bus used for cab - to - command station communication, and vice - versa.
c
separation of layout into indendently - controlled blocks.
U.S. equivalent of guard's van/brake van.
C
A small subsidiary signal, fixed below the main arm which when cleared allows a train to enter an occupied section of line and proceed with caution.
Cambrian Railway. This Welsh company had its headquarters curiously situated in North Shropshire, England!. Its main lines were from Shrewbury to Aberystwyth and Pwhelli. Based on r...
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This Welsh company had its head quarters curiously situated in North Shropshire, England!. Its main lines were from Shrewsbury to Aberystwyth and Pwhelli. Based on route length and area c...
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c
electric motor with side magnets enclosed in thin metal box, developed originally for slot car racing.
C
A device for storing a charge of electricity.
c
common English term for passenger coach.
gradual relegation of wearing rolling stock to less demanding or pretigious uses.
arrangement of suspended wires for overhead current collection.
the overhang of the centre of a long vehicle on the inside of a sharp bend.
iron castings spiked to sleepers (ties) to secure rails.
C
An impedance, used to damp out ac ripples in a rectified circuit.
Raised longitudinal section of a carriage roof, used to give additional daylight and ventilation for gas lighting. Common in late 19th Century carriage design.
c
roof with central vertical extension the sides of which are glazed.
C
locomotive with three driving axles (six wheels) on each bogie.
c
vehicle for accommodation of passengers (car in U.S.)
contact rubbing on live rail or wire to pass electricity.
C
Term used to describe signals which are electrically operated and use lamps with coloured lenses to display the aspects (see MAS).
The command station receives electrical signals (operator instructions) from the cab. The command station then creates NMRA DCC digital packets in accordance with NMRA spe...
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A system of wiring where a number of controllers, each with its own independent power supply, are connected to a common return rail.
c
contact ring on armature shaft split into segments corresponding to number of windings, receiving current from brushes.
C
A claim made by a manufacturer that their product will generally work with other compatible devices in areas where both devices support a given function.
Same as conformance. A compliant product is one that has passed NMRA tests and earned an NMRA Conformance Warrant.
c
U.S. term for bellows gangway between coaches.
U.S. equivalent of guard, in charge of train.
C
A configuration variable, or CV, is a defined piece of information used by the decoder to adjust its operation. This information is permanently stored inside the decoder until the user wishes t...
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Products that have passed the NMRA's extensive testing procedures are eligible for a Conformance Warrant if the manufacturer also agree to fix any discrepancies that might become apparent in the futu...
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An official document awarded by the NMRA to a manufacturer for a specific product that has demonstrated conformance to NMRA Standards and applicable Recommended Practices by virtue of Passing all app...
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Heavy section metal rods on a steam locomotive. These transfer the liner tractive force from the pistons into reciprocating motion which turn the driving wheels and propel the locomotive forwar...
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A device to connect wires, etc.
Operating and controlling several locomotives as if they were a single entity. For example, several diesels might be connected together to provide more power for a steep grade. Also calle...
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A device for completing a circuit, usually in switches and relays (qv). Normally "a pair of contacts" or "contacts".
The bus used for transmitting digital packets from the command stations to power station.
A selection of switches and other devices, mounted on a board, to provide control for a model railway.
A device for controlling the speed, and generally the direction of travel of a locomotive.
Solder in the form of a hollow wire containing flux.
c
device for connecting vehicles into train.
C
Large metal rods that connect the driving wheels of a steam locomotive. Their purpose is to distribute the tractive force to each of the driving wheels.
This Glasgow based firm formed the northern leg of the West Coast Main Line, from Carlisle to its home city. It also owned important routes from Glasgow to Edinburgh, Perth and Aberdeen.
The name given to a design of early express locomotives in which a single axle with two large diameter driving wheels was located at the rear of the locomotive, thus allowing a low slung boiler.
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A railwayman that operates a remote level crossing and who often resides in an adjacent crossing keeper's cottage.
c
pointwork allowing a train to divert to a parallel line.
longer than standard sleeper (tie) beneath point ect.
C
A small bridge or short tunnel provided to take a stream or ditch under the railway trackbed.
The flow of electricity in a circuit.
The amount of electrical flow required by an operating device.
A device for breaking a circuit, should the current flow become excessive. See fuse.
c
excavated channel through rise of ground.
D
Digital Command Control is one of several methods of controlling and/or operating a model railroad layout. The control information is provided in the form of a digital signal instead of a stand...
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An insulated crossing in the track.
d
printed lettering or design which can be transferred to vehicle.
D
A device that receives and acts on digital packets created by the command station. See also "Accessory decoder", "Locomotive decoder", "Mobile decoder", "Stat...
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A device for sensing the presence of a train.
d
another term for bellows or concertina connection.
D
A locomotive powered by a diesel engine which uses an electric transmission system to transfer the power from the engine to the locomotive wheels. Essentially the engine is linked to an alterna...
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A locomotive powered by a diesel engine which uses a hydraulic transmission system (See Torque Converter).
A locomotive powered by a diesel engine uses a mechanical system of transmission. Essentially the engine is linked to the driving wheels through a conventional gear box.
Referring to the replacement of steam locomotives by diesel locomotives and other modern forms of diesel traction.
A digital packet is a defined sequence of bits that instruct the decoder how to respond. See also bit and byte.
An electronic device which only permits current to flow in one direction.
A signal which gives an advanced indication of the setting of the next home signal. Semaphore distants have fishtail ends and since the 1920s have been painted in the familiar yellow colour.&nb...
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The name for each of the signal posts fitted to a bracket or gantry signal.
d
fitting on top of boiler from which steam is led to cylinders.
D
A track formation which permits trains to travel over a crossing in more than one direction; a complicated device.
d
steam engine where steam is applied alternately to either side of piston(s).
coach etc. with accommodation on two levels.
connection of two locomotives to one train.
complex point allowing crossing other lines with additional rail allowing train to move on to one of several tracks.
D
Double pole, double throw (switch).
Double pole, single throw (switch).
d
early trackless steam locomotive model.
D
The main wheels of a locomotive which provide the tractive force to move the train. Non-driving wheels are called bogie and pony wheels
d
type of wagon body which can be tilted to discharge load.
E
The southern half of the English lines of the former LNER. The Eastern and North Eastern Regions were combined into one in the 1970s.
Abbreviation for the East Coast Main line. Used to describe the line from Kings Cross through York and New castle to Edinburgh and Aberdeen.
Electrically-Erasable Programmable Read-Only Memory. These computer memory devices are used to storedata in a manner that is easily read, but that changes infrequently. Most decoders use ...
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A locomotive powered by electric current which can be picked up from either a 3rd rail or overhead wire. The current is used to drive conventional electric traction motors linked to the driving...
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e
conductive rod used for quick closing of electric circuits.
E
Electrical circuits involving either the obsolescent thermionic valve or, more commonly, devices including transistors (qv) and microchips (qv).
18.2 mm gauge, 4 mm to the ft, 1:76 scale.
e
built - up track base over dip in ground.
E
e
overhang of long vehicle ends on sharp curve.
U.S. term for engine - driver.
E
Erasable Programmable Read-Only Memory. These computer memory devices are used to store data in a manner that is easily read, but can only be erased and reprogrammed with special tools.
F
The unit of measurement of capacity; very large, hence microfarads are more commonly employed.
A term often used to describe a specific type of route indicator fitted to colour light starting signals. Feathers are rows of small white lamps enclosed in a casing and are fitted to signals w...
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The electrical input to the controlled rail on a layout.
In DCC: The ability of a device to transmit information regarding its status back to the command station.
f
area of layout, often concealed, where trains can be made up manually etc.
F
In railway terminology, the person responsible for stoking the fire, regulating water levels and maintaining boiler pressure on a steam locomotive.
f
connector between ends of length of rail holding ends firmly in alignment; sometimes erroneously relied on for electrical connection.
extraneous material on moulding where dies were not sufficiently tight together.
platform wagon for self-supporting loads.
F
An electronic circuit which will take up one of two states, and remain so until triggered.
A paste or fluid employed in soldering.
f
locomotive platform for driver and fireman.
F
A railway term used to describe the track, meaning the space in between the running rails, derived from the standard gauge of 4ft 8½ins.
An early attempt at building a "fireless" steam locomotive with the objective of ridding the underground sections of London's Metropolitan Railway of smoke.
f
U.S. term for goods van (also boxcar)
break in rail permitting wheels to cross (in pointwork).
F
The ability to specify (ie map) which function buttons on a cab activate which specific decoder function outputs. This defines which decoder wires are active for each user input.
In DCC A decoder controlled switch that can be turned on and off by a user's cab action.
A device, generally a thin wire, which ruptures should the current flow in a circuit be excessive. See also cut-out.
G
45 mm (1) gauge, scale chosen to suit modelled prototype.
A railwayman who works and maintains the track and the associated permanent way.
Normally used to describe the flexible corridor connectors between carriages that allows passengers to move from one to the other.
g
the actual width, centre width, centre to centre between rails.
G
A committee set up in 1845 to deliberate over the merits of Brunel's "broad" gauge against Stephenson's "standard" gauge.
Formed out of the Long Established MSLR (Manchester, Sheffield & Lincolnshire Railway), it renamed itself upon completion of its main line through to London, via Rugby and the Chilterns.
This famous railway served most of East Anglia, almost having a monopoly of lines heading east out of London. With its HQ at Stratford in the East End, its principal line was from London (Liver...
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Serving from the north eastern home counties, through Lincolnshire and Nottinghamshire to Leeds. This railway formed the southern half of the East Coast Main Line.
Great North of Scotland Railway. Serving the northern part of Aberdeenshire, as well as Banff and Moray, this small concern had its main route from Aberdeen to Elgin. It also served much ...
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g
U.S. platform wagon fitted with low sides.
train carrying materials, produce etc. (U.S. freight train).
slope or incline, usually expressed as a ratio, e.g. 1: 120.
G
Small marker boards used to indicate the rate at which the track is inclined up or down.
As the name implies these are signals placed at ground level. They can be discs, miniature semaphore arms, or small electric lamps. They are used mainly to signal shunting manoeuvres.
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The 1923 amalgamation of the vast majority of independent UK railway companies into four regional conglomerates. Namely the LMS, LNER, GWR, and SR.
This company's lines ran from Glasgow down the Ayrshire coast south to Stranraer and also via Kilmarnock to Carlisle.
g
official responsible for train, other than driving.
G
Great Western Railway. Unlike other companies, the great Western Railway, which had been incorporated in 1835, merely absorbed the independent Welsh railway companies. Due to their relati...
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Unlike other group companies, the Great Western Railway, which had been incorporated in 1835, merely absorbed the independent Welsh railway companies. Due to their relatively small size this gr...
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H
16mm, 16.5 mm, 5/8 in gauge, scale nondescript (thankfully obsolete).
h
electronic means of controlling current supply allowing very precise control and full power irrespective of speed.
H
In DCC A portable cab used by the model railroad engineer (operator) to control one or more locomotives. Simple handhelds may have speed and direction controls only. Specialized cab...
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h
trackwork allowing a locomotive to move away after pulling a train into a terminal platform.
H
The load bearing end cross member of a rail vehicle. Also known as the buffer beam.
16.5 mm gauge, 3.5 mm to the ft, 1:87 scale.
An isolated section used to hold trains in hidden loops, etc. Hertz, the measurement of frequency; in practice, the number of cycles per second.
This refers to the first stop signal that a train encounters when it enters a block section controlled by a signal box. There may also be "outer" home signals in a block section too.
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10.5 mm gauge, 3.5 mm scale.
Colloquial name for hopper wagons. An open or enclosed wagon in which the body tapers at its base and is provided with a bottom door through which the load is discharged.
h
a type of non-scale coupling, reasonably simple to operate.
H
With headquarters in Inverness, this company operated some of the most scenic routes in the UK. Its lines included those to Perth, Keith, Wick and of course the charismatic line to the Kyle of ...
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Hertz, the measurement of frequency; in practice, the number of cycles per second.
I
A quality of a coil of wire which carries an ac or fluctuating current. Its effect is similar in action to a resistance.
A lamp mounted on a panel to provide an indication of the state of a circuit, or a length of track.
A fishplate made from plastic material to provide an insulated joint in the track.
A break in the track, which is insulated to provide isolation.
i
U.S. term for signal box.
layout area allowing operator to walk round all sides.
I
A section of track that can be isolated by means of a switch or similar device.
j
free-ended multi-strand electrical cables plugged in when portable sectionalised tracks are reassembled.
K
In DCC Kilobits per second (alsoKbps) refers to the speed of data transmission on various buses. For example 2.2Kbps transmission passes data at 2200 bits per second. See also bus a...
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A type of switch formerly used in telephone exchanges, frequently provided with a large number of contacts.
L
The Liverpool and Manchester Railway, opened in 1830, this is accredited as being the first public, steam powered passenger carrying railway in the UK.
Based in Manchester, it had a busy trans-Pennine network, linking Lancashire and the industrial areas of Yorkshire.
l
arrangement of parallel rows of siding.
L
In DCC Local Area Network is a computer term referring to the interconnections by which various computers and devices communicate with each other in a geographically small location.
A relay which remains held even when its operating current no longer flows.
l
carrying wheels ahead of driving wheels on locomotive.
L
Light-emitting diode, an electronic device which emits a small amount of light when current passes through it.
Area of land immediately surrounding and adjacent to a railway line.
l
consistent colour scheme employed by railway to identify/pubblicise their locomotives and other rolling stock, vehicles etc.
L