Steve's Railway Glossary

This rather long page contains definitions of a large number of both prototype and modelling terms mostly intended as an introduction for beginners but some more advanced terms are included as well so whatever railway term that you are looking for, you might find it here.
To search for the term that you require please click the letter that the term starts with in the alphabetical links above.

If the term that you want defined is not included or you think that you have a better definition of one of the terms that is defined, please send me an email.



Absolute Block
A section of track protected by signals into which only one train at a time is permitted.
Advanced Starting Signal
An additional signal placed beyond the starting signal to permit trains to be shunted beyond the departure end of the platform. The advanced started indicates station limits at the departure end of the platform.
Locomotive with 2-6-6-6 wheel arrangement (refer Whyte)
Locomotive with 4-4-0 wheel arrangement (refer Whyte)
Locomotive with 4-14-4 wheel arrangement (refer Whyte)
Locomotive with 4-4-2 wheel arrangement (refer Whyte)
Auto Train
An early form of multiple unit where a steam locomotive was built into the end of a railway carriage.
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Back to Back
The distance measured between the inside edges of the two wheels on an axle. Important for determining if a given wagon, carriage, or locomotive will run through a given piece of track that has check rails.
The base material into which the sleepers under the track is set.
Baltic (or Hudson)
Locomotive with 4-6-4 wheel arrangement (refer Whyte)
The plate upon which flatbottom rail is laid in order to be fastened down. Usually referred to in modelling terms as "chairs".
Bay Platform
A shorter terminating platform road set into the side of a larger platform
Locomotive with 2-8-4 wheel arrangement (refer Whyte)
Locomotive with 4-8-8-4 wheel arrangement (refer Whyte)
Block or Section
A section of track protected by signals.
see Section
Broad Gauge
Track having a gauge wider than standard.
Locomotive with 2-12-4 wheel arrangement (refer Whyte)
Bullhead rail
Rail having the same profile for both the upper and lower portions of the rail.
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A piece of rolling stock used to convey passengers.
Carriage Shed
A shed used for the storage of passenger carriages
Catch point
A single trailing point blade set into an ascending track to derail wagons which have come uncoupled and are running back down the hill. This prevents runaways colliding with a following train.
Capacitor discharge unit. Used to store power so that several point motors may be fired simultaneously.
The base into which bullhead rail is laid in order to attach it to the sleepers.
Locomotive with 4-6-6-4 wheel arrangement (refer Whyte)
Check rail
The piece of rail which holds the inside of the wheel to stop the other wheel from going down the wrong side of the "frog". Also used on bridges etc. to help hold the wheels on the track.
Closure rail
The piece of fixed rail between the points and "frog" of a turnout.
Coaling Stage
A tower like arrangement over a track into which coal is mechanically loaded. The coal can be dropped directly into the tender of steam locomotives.
Colour-light signal
A signal that uses only coloured lights to provide an indication of how far in front of the train that the line is clear.
Locomotive with 2-4-2 wheel arrangement (refer Whyte)
Common return
A method of wiring a layout whereby all of the wires going to one side of the track are wired together and permanently connected to one side of all controllers. This method permits single pole switches to be used in place of double pole and reduces the amount of wire required. IT CANNOT BE USED WITH SINGLE SUPPLY.
Compound Ladder
A way of splitting one track into many in the shortest possible distance by placing another turnout on each track coming from the previous one.
Locomotive with 2-6-6-6 wheel arrangement (refer Whyte)
A notation used to identify the wheel arrangement of locomotives by specifying non driving axles by numers and driving axles by letters (followed by 'o' if they are not coupled). For example C-C means no leading wheels, two sets of six coupled/driving wheels, and no trailing wheels, Co-Co indicates the same except that the driving axles are independently powered and not coupled together, A1A-A1A is a similar wheel arrangement except that the centre pair of wheels in each set are not powered. This notation is commonly used for diesel and electric locomotives.
Continuous Run
A layout upon which a train can be set in motion and can then run continuously round and round traversing the same circle of track.
The unit consisting of switches and knobs used to control the speed and direction of a model train. The unit may also contain more sophisticated controls (eg. inertia). A transformer may also sometimes be found in the same box.
A pair of turnouts arranged so as to permit a train to cross from one line to another.
A section of railway line where the surrounding countryside is at a higher level than the line and the ground has been dug away to put in the line.
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Dead Frog
A model turnout where the crossing vee is moulded of plastic so as to keep the two track circuits through the turnout entirely separate.
Locomotive with 0-10-0 wheel arrangement (refer Whyte)
Diesel Locomotive
A locomotive powered by a diesel engine. The variations diesel mechanical, diesel hydraulic, and diesel electric refer to the method used to connect the diesel engine to the wheels.
Diamond Crossing
A track unit where one track crosses another track at the same level.
Diode Matrix
A circuit using diodes that permits route setting of points to be done by selecting one circuit instead of requiring each point to be set separately.
Distant Signal
A signal giving an advanced warning of what the next signal is showing. It has no stop indication.
Dog bone
A continuous run layout where the two sides of the circle have been "squeezed" together so as to simulate double track. A train running on this type of layout will appear to be running backwards and forwards in a realistic manner.
Locomotive with 4-4-4 wheel arrangement (refer Whyte)
Double slip
A diamond crossing having slip roads on both sides of the diamond.
A means of getting into a central operating area of a layout not having a lifting section. May be padded on the underside of the baseboard to lessen the impact when you try to stand up too soon.
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Electric Locomotive
A locomotive powered by an electric motor. Electricity is supplied either by overhead wires or via an additional rail near the running rails. This extra rail is called the conductor rail.
Electric Train Heating (ETH)
A method of heating a train using electricity.
A section of railway line where the surrounding countryside is at a lower level than the line and the ground has been built up to put in the line.
End to end
A layout upon which a train set in motion from any one position will eventually have to stop and reverse direction in order to be able to return to its starting point.
End to Loop
A layout not having a continuous run but having at least one section of track from which a train can be set in motion and eventually return to its starting point without having to be reversed. The train does however need to stop and reverse before being able to repeat the run.
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Facing crossover
A crossover arranged so that trains can pass from one track to the other while travelling forwards.
Feed point
The place at which power is fed into the track on the model.
A non-scenicked part of the layout that is used to store trains. A place to represent the rest of the rail network and make it easier to develop a meaningful timetable.
Figure eight
A type of layout where the continuous run crosses over itself in the shape of the number eight.
An alternate name for rail joiners.
Flat bottom Rail
Rail having the lower portion of the rail wider than its upper portion.
Foreign Visitor
A piece of rolling stock that did not run regularly on the prototype railway on which your model is based. It may belong to a different railway company, country, or period.
Four Aspect
A colour light using four lights. From top to bottom the lights are yellow, green, yellow, and red. A red indication means that the next section contains a train. A single yellow indication (using the lower yellow) means that the next section is clear but there is a train in the following one. A double yellow indication means that the next two sections are clear but there is a train in the one beyond that. A green indicates that the next three sections are clear. Depending on the speed of the train, it will need to commence slowing on either a single or double yellow.
A model not based on any particular prototype. May incorporate features from several different prototypes.
A modelling term used to refer to that part of a turnout that consists of the crossing vee and wing rails.
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Gas Turbine Locomotive
A locomotive powered by a gas turbine engine. This type of locomotive was experimented with but never came into regular use.
The distance between the two running rails on a single piece of track.
Goods Shed
A shed with a built in platform where smaller goods are loaded into vans.
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A piece of track feeding a number of sidings that permits the sidings to be shunted without blocking the main line.
Home Signal
A signal separating one signalling block from another. Found at the approach end of station platforms and other places to protect a permanent risk (eg. points, a dead-end, derailer, level crossing).
Hudson (or Baltic)
Locomotive with 4-6-4 wheel arrangement (refer Whyte)
Locomotive with 2-4-4 wheel arrangement (refer Whyte)
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Individual supply
A method of powering a layout where each controller has its own separate transformer.
Inside slip
A type of slip where the slip road(s) overlap inside the diamond
Island Layout
A layout having an access way all around the outside of it. A layout which is not adjacent to a wall.
Island Platform
A platform having tracks running on both sides of it.
Isolating Section
A short section of track fed by a switch or pushbutton from an adjacent track section. May also be fed by a diode so as to only permit travel in one direction.
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The spot at which a branch diverges from the main line. It may consist of a single turnout for single track or may consist of several turnouts and diamond crossings for double (or multiple) tracks.
Junction Signal
A signal which as well as indicating the state of the track ahead also indicates which of two or more different available tracks that the train will actually take.
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A model that has been constructed mostly by modifying the parts from a kit that was intended to build something else.
A model constructed from a kit in accordance with the instructions supplied with the kit.
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Lever Frame
A frame holding levers for operating turnouts and signals. Can be found both in signal boxes and, where only a small number of levers are required, outside.
Live frog
A model turnout where the crossing vee is made of metal and hence needs to have its polarity switched whenever the points are thrown.
A piece of rolling stock whose primary purpose is to provide the means by which other rolling stock is moved.
A line that runs parallel to another line to which it is attached at both ends.
Looped eight
A type of layout similar to a figure eight except that one half of the "eight" has been twisted around inside of the other half. Trains on this type of layout go around twice before returning to their starting point.
Low Relief
Scenery close to the back edge of a model railway that has been modelled to a reduced depth to give the illusion that the scenery extends much further than it actually does.
Lower Quadrant
A semaphore signal that lowers its arm to indicate that the line ahead is clear.
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Locomotive with 4-10-0 wheel arrangement (refer Whyte)
Locomotive with 2-8-2 wheel arrangement (refer Whyte)
A section of the layout which can be repositioned into a different place in the layout each time that the layout is reassembled.
Locomotive with 2-6-0 wheel arrangement (refer Whyte)
Motive Power Depot (MPD)
A servicing depot for steam locomotives. Usually has a turntable, loco shed or roundhouse, coaling stage or tower, water crane, etc.
Locomotive with 4-8-2 wheel arrangement (refer Whyte)
Multiple Unit
A type of passenger train where the diesel or electric motor is built into the carriages themselves.
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Narrow Gauge
Track having a gauge that is narrower than standard.
Locomotive with 4-8-4 wheel arrangement (refer Whyte)
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Open Top
A layout where the solid baseboard only exists under the track areas. Self supporting scenery is built around the track at both higher and lower levels.
Outer Home Signal
An additional signal placed before the home signal that protects trains shunting back past the home signal. Indicates station limits at the approach end of the station.
Outside Slip
A type of slip where the slip roads are entirely outside the diamond.
Locomotive with 4-10-2 wheel arrangement (refer Whyte)
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Locomotive with 4-6-2 wheel arrangement (refer Whyte)
Someone who lays the rails/track upon which the trains run.
That part of a station where passengers board and disembark from trains.
Point motor
A single or double solenoid device attached to a turnout so that the points may be operated electrically from a remote location. Single solenoid require a continuous supply whereas double solenoid operate on a pulse.
The moving blades within a turnout that determine the route that a train will take. Also used as catch points and trap points.
A layout that can be broken up into sections that can be easily handled by one person. Sections on a portable layout do not usually exceed 1200x330mm. A portable layout may be disassembled for storage between operating sessions.
Locomotive with 2-6-2 wheel arrangement (refer Whyte)
A model that has been produced by modifying a ready-to-run model so as to make it into a model of something else.
The original 12 inches to the foot (or 1000mm to the metre) original upon which the model is based.
Push Pull
A type of train where the carriages are kept permanently coupled to the locomotive (usually a tank loco) which pulls them in one direction then pushes them in the other.
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A piece of shaped metal along which a wheel is run or which is used to hold a wheel against another rail.
Rail Break
A gap in the rail that divides one track section from another on the layout. May be created using plastic (insulating) fishplates between the two sections of rail. Track sections will usually be separated from one another by isolating both rails while isolating sections will usually only isolate one.
A model that has already been completely built by the manufacturer prior to its purchase. It can be taken straight out of the box, placed on the layout, and run.
An electrically operated switch
Reverse loop
A line which curves around and is attached back to itself to allow trains to be turned. Not often found on the prototype. Requires special wiring on two rail model systems.
Rolling Stock
Anything with wheels on it which can run on the track including locomotives, carriages, goods wagons, and maintenance vehicles.
A curved shed found next to or around a turntable for storage of locomotives.
Running rails
Rails used to support the wheels of trails running over them.
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The ratio between the size of the models and the size of the prototype. This can be expressed either as a ratio or as so many millimetres per foot (or fractions of an inch per foot for American models). Usually only applicable to the rolling stock and buildings as the rest of the scenery is usually condensed to fit the available space.
Every part of a model railway apart from the baseboards, track, wiring, and trains.
Scenic Break
A means of dividing up a model railway to give an impression that two areas are much further apart than they really are. This can be done using a tunnel where the two tunnel mouths which in reality are only centimetres apart are separated by a scenic divider and imagined to be many kilometers apart. The same effect can be achieved by disappearing a train under a bridge or into a cutting.
A model made entirely (or at least mostly) from parts that you have made yourself.
Section or Board
The component parts into which a layout or module can be broken up for transport. Sizes may vary between 1200mmx300mm and 2400mmx1200mm depending on the method of transporting the layout and the number of people available to carry the board.
Section (signalling)
see block
Sector Plate
A plate having one or more tracks on it which is pivoted at one end. The plate is moved to align the various tracks on the plate with one or more adjacent fixed tracks.
Semaphore Signal
A signal that uses a moving arm to indicate the state of the line ahead. Having the signal arm point straight out usually indicates that the next section contains a train. A raised or lowered arm indicates that the line ahead is clear. The signal usually also contains a lamp in front of which coloured filters are passed in order to provide an indication of the arm position at night time.
Shunting signal
A smaller than normal signal that is used specifically to indicate whether or not particular shunting moves may take place. Not usually modelled on layouts.
A single piece of track attached to a mainline or headshunt at one end only. The other end will usually be terminated with a buffer stop so as to ensure that trains do not run off the end.
Siding (American)
American prototype terminology for a loop.
Signal Box
A building from which the surrounding turnouts and signals are operated. May contain either a lever frame or in more modern signal boxes a panel containing switches and coloured lights.
Simple ladder
A way of converting one track into many by attaching turnouts together so that only one of the exit roads from each turnout feeds the next.
Single slip
A diamond crossing having a slip road on only one side of the diamond.
Single Supply
A method of powering a layout where all controllers are powered by the same transformer (which therefore needs to be powerful enough to power as many trails as you intend running at the same time). CANNOT BE USED WITH COMMON RETURN.
Sleeper or tie
A piece of timber or concrete that (usually) runs perpendicular to the rails and supports the rails.
The coil of wire within a point motor or relay through which power is fed to operate the unit. The coil of wire will act as a magnet when a current is fed through it.
A type of diamond crossing where trains can slip from one of the crossing tracks to the other.
Solid Top
A layout having a solid baseboard across the entire board. Scenery is only at and above track level and is supported on the board.
Split potential
A method of powering a layout using two transformers (one for the trains travelling in one direction and one for the trains going in the other direction). Cannot be used with transistorised controllers as the switching needs to be done on the feed side of the controllers.
American prototype terminology for siding.
Standard Gauge
The original track gauge first used by the ancient Romans and adopted by early railway builders in England.
The complete area including platforms, goods yard, MPD or TMD, and carriage sidings that is contained within the one control area. The length of a station is measured between shunting limits (from outer home to advanced starter) and may extend to different distances on the different arrival and departure tracks.
Starting Signal
An extra signal placed at the departure end of a platform so as to allow trains to run into the station and stop even though there is a train in the next section.
Steam Heating
A method of heating a train using the steam from a steam locomotive.
Steam Locomotive
A locomotive powered by a steam engine. This has been the most common form of propulsion for most of the time that railways have existed.
Stock rails
The outside running rails through a turnout.
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Tank Locomotive
A steam locomotive where the water tank and coal bunker are built into the locomotive so a tender is not required.
A piece of rolling stock permanently coupled to a steam locomotive to carry coal and water.
A station found at the end of a railway line where departing trains have to travel back in same direction out of the platforms as that from which they arrived.
Locomotive with 2-10-4 wheel arrangement (refer Whyte)
Three Aspect
A colour light using three lights. From top to bottom the lights are green, yellow, and red. A red indication means that the next section contains a train. A yellow indication means that the next section is clear but there is a train in the following one. A green indicates that the next two sections are clear. A train will need to commence slowing on a yellow signal.
see Sleeper
The metal bar or sleeper that attaches two points together and forces them to operate together.
The "road" on which trains run. Track is made up of rails, sleepers, and chairs or baseplates.
Track Plan
A diagram showing the arrangement of tracks on a layout. It can be either a to-scale drawing or a schematic diagram.
Track Section
A section of track that is isolated from the rest of the layout by section breaks and which has its own track feed and section switch.
Traction Motive Depot (TMD)
A modern version of the MPD which stores and services electric and diesel locomotives.
Trailing crossover
A crossover that requires trains to reverse in order to transfer to the other line.
Train turntable
A turntable big enough to turn complete trains. Used only in fiddle yards.
The unit which converts the household mains voltage down to the much lower and safer voltages that we use to run our trains.
A layout which can be broken up into sections to allow the room to be cleaned or to transport the layout to an exhibition. A layout of this type is usually left assembled between operating sessions and usually requires more than one person to assemble and disassemble it. Sections may be as large as can be conveniently transported.
Trap point
One or more point blades operating in conjunction with a mainline turnout such that when the turnout is set for the main line that any train approaching down the other line will be derailed before it blocks the main line. Also referred to on the model as a "catch point".
A plate having one or more tracks on it which is moved sideways so as to align it with one or more fixed tracks.
An arrangement of tracks using three turnouts and shaped somewhat as its name suggests that permits locomotives or complete trains to be turned. This formation requires special wiring for two rail models.
A section of track completely covered and travelling beneath the ground.
A track formation that allows a train to choose between two or more possible routes. Made up of stock rails, points, closure rails, check rails, wing rails, crossing vee, and tiebar.
A rotating platform for turning locomotives or wagons. On the model may also be used to turn whole trains.
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Uncoupling Ramp
A ramp fitted under or between the rails on a model to facilitate the remote uncoupling of rolling stock. It has no prototype equivalent except where used in hump shunting yards.
Upper quadrant
A semaphore signal which raises its arm to indicate that the line ahead is clear.
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The part of the "frog" of a turnout upon which the train wheels will run. The part of a turnout where the inside running rails come together.
A long form of arched bridge having five or more arches below track level.
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A piece of rolling stock used for the conveyance of freight.
Wagon Turntable
A method used in the early 1900s (and before) to turn wagons so as to run them into sidings at extreme angles to the rest of the track or where there was insufficient space for a turnout.
Walk around layout
A layout not requiring a duck-under or lifting section.
Water Crane
A crane like device used to provide water for steam locomotives.
A notation used to identify the wheel arrangement of locomotives by specifying first the number of leading wheels, then the number of coupled/driving wheels, and finally the number of trailing wheels. For example 0-6-0 means no leading wheels, six coupled/driving wheels, and no trailing wheels, 4-6-6-4 indicates four leading wheels, two sets each of six coupled/driving wheels, and four trailing wheels. This notation is commonly used for steam locomotives.
Wing rail
The extension of the closure rails of a turnout along each side of the crossing vee to help hold the wheels on the track.
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Copyright Stephen Chapman