Build a Model Railway

Glossary  (For the beginner)

AC – Acronym for alternating current, this electricity supply method makes use of alternating (switching direction back and forth) electrical flow at various rates per second or cycles per second. Two common cycle rates are 50 (UK, Europe) and 60 (USA, Japan) hertz (Hz). AC uses higher voltages and lower ampres (amps) to deliver electricity when compared with direct current (DC).

Amp – Apart from being a device or component used in transforming acoustical ‘unplugged’ musical instruments and vocals into amplified sounds, the amp, or ampere for which it is short for, is a measurement for the amount of electrical current either in storage (like a battery) or on the move in a circuit.

Ballast – Generally, the purpose of ballast is to provide stability whether to limit electrical current, level a submarine at various depths or stabilise a real and model train track. Usually made up of small grain or crushed rock, ballast gives the railway a pliable suspension by effectively ‘bedding in’ the track sleepers.

Baseboard – A large sheet usually made of plywood (but can be other materials) that forms the base or foundation layer of the model railway to which the track, scenery and other structures (e.g. buildings, bridges, tunnels) are attached.

CDU - A Capacitor Discharge Unit enables better point performance and improves the lifespan of solenoids.

Controller - Similar to real-world human train controllers (but now-a-days are preoccupied with logistics as train delays, service faults and dealing with irate travellers late for work), model railway controllers are devices that connect to and control track and trains. Things they control include train speed and direction and track switching. There are two main types: DC (analogue Direct Control) and DCC (Digital Command Control).

DC - Acronym for direct current, this electricity supply method uses the single flow electrical current between two poles, positive and negative and is the method commonly used for batteries. DC uses lower voltages and higher amps to deliver electricity when compared with alternating current (AC). Note: Not to be confused with Direct Control - also referred to as DC.


DCC – Acronym for Digital Command Control, this integrated modular control system allows for programmed control of multiple locomotive switching without the need to create separate electrical blocks that isolate each engine. Requirements are DCC controller and a signal decoder for each locomotive.

Decoder - In the digital world, a decoder is software and/or a protocol running on a device (such as a controller) that takes the signal from an encoder (the same only reverse) and deciphers it so that it can be understood by another component such as a locomotive in a DCC setup.

Fiddle Yard - (Staging Yard, Train Yard, etc.) Tracked areas in railway design designated for train and rolling stock storage, organisation and manipulation away from the main track runs and scenery. They can include things like remote controlled turntables and multi-story train parks and can be visible or hidden from view.

Frogs - See Point Motors

Gauge - See Scale

GWR Rail Network – Great Western Railway (Founded 1833 – 1947)

Inverter – This does the opposite function of a transformer by converting direct current (DC) to alternating current (AC) as found commonly in house mains circuits.

LMS Rail Network - The London, Midland and Scottish Railway (1923 – 1947)

LNER Rail Network – London and North Easter Railway (1923 – 1947)

Plaster - A building material used for the protective or decorative coating of walls and ceilings and for moulding and casting decorative elements.

Point Motors - These are used at the point where two or more converging tracks cross or merge using frog switches (or just frogs - a point of track with switchable rails) to ensure the train travels along the correct track path. These track points are called such as the converging rails appear as webbed frog legs (Vive les cuisses de grenouille!).

PSU - Stands for power supply unit or just power supply.

Reverse Loop - This is where a track leaves a circuit and then re-joins it with the train going in the opposite direction.  This will result in a short circuit unless the section is isolated from the rest of the circuit.

Rolling Stock - This term, in the rail transport industry, refers to any vehicles that move on a railway. It usually includes both powered and unpowered vehicles, for example locomotives, railroad cars, coaches, and wagons.

Scale - (aka Gauge) Refers to the size the railway, train, construction and scenery has been built to and can be represented as a fraction, ratio (e.g. 1/87, 1:87, etc.). or the standardised O (1:48), OO (1:76) and the HO (1:87) railroad which is more common in the US & Canada. There are others such as S scale (1:64) and N scale (1:160) but these are less common.

Sleeper – As in real-world railway construction, the track sleeper’s purpose is to transfer the load from the parallel rails, which are perpendicular to sleeper, to the ballast underneath, giving the track its iconic criss-cross pattern.

Soldering – A semi-permanent method, using temporally liquefied alloy (solder), for making connections directly between bare wire, metal contacts and joining metal components together. Dating back thousands of years, soldering has been used to make tools, jewellery and many other items. For the railway modeller, wiring up connections for track, point motors and power leads make up the majority of uses. Soldering can be done, at its most basic, with just a lightweight 25-30w pen and rosin-core solder but solder flux or paste and braid or a de-solder pump add quality and convenience to the method.

Solenoid – A common component that makes use of its electromagnet, normally a copper coil with an iron rod (the plunger) in centre in order to operate a switch. When an electrical current is passed through it (making a magnetic field) the solenoid’s plunger punches out to ‘throw a switch’.

SR Rail Network – Southern Railway (1923 – 1947)

Static Grass - Used in railway modelling and miniature war gaming to create realistic-looking "grass" textures. It consists of small coloured fibres charged with static electricity, making them stand on end when sprinkled onto a glue-coated surface.

Transformer – A component that converts one voltage to another such as 220v to 110v (this would make it a step-down transformer). Transformers are often used in AC - DC converters which power or charge devices like phones and laptops from normal house current.

Voltage – This is the element of electricity that regulates its flow from one point to another, such as from the wall socket to the train track. The more voltage there is, the more pressure there is on the current to move. Think of it like a water hose or pipe with the water being the current and the pressure (or speed at which it comes out) being the voltage.

Voltage Regulator (adjustable) – A device or a component which either steps a voltage up (boost) or down (buck) to a desired level, therefore, it is often referred to as a boost or buck converter. When it is a separate device (not as a component of an adjustable PSU), it will require a power supply with suitable voltage and amperage within the regulator’s ranges.