Model Railway Wiring Basics | Part 1 of Model Railway Electronics

New to model railways and confused by the wires, leads, boxes and connections or want to refresh your knowledge of the basic electrics involved? Here’s the guide to get you started.

Welcome to the first in a series of articles on model railway electrics. Overcoming articles I’ll be explaining, in simple jargon-free language, everything you need to know to set up and operate your railway regardless or scale or make – be it Hornby, Peco, Bachmann or another manufacturer.

This first guide will start at the beginning but over the series, I’ll cover all you need to know, right up to complex digital layouts.

In case you’re wondering, aside from being a life long model train enthusiast and having built numerous layouts I was also a trained electrician and spend my working day building computer networks for large websites so electrics, railways and digital networks are my bread and butter. Read About for more information.

Identifying The Basic Elements Of An analogue Model Railway

At the heart of any analogue model railway starter set, such as those from Hornby or Bachmann, are three key electrical items.

  • A Transformer
  • A Controller
  • The Layout Wires

The Transformer

hornby transformerThe transformer is often a solid heavy black plastic box with an attached lead and plug. It’s also possible for the transformer to be hidden inside the controller — which I’ll get to next — or sometimes disguised as a bigger than a normal plug.

The transformer converts the electricity coming from the mains power wall sockets in your house to the lower, safer, supply needed to run the railway.

I’ll discuss the fundamentals of electricity — AC, DC, volts, amps and current — in a future article. All you need to know is that there are two forms of electricity. There is AC, which comes out of the wall sockets, and DC – which the majority of electrical devices in your home run on – and the transformer converts one to the other.

MRE Tip: Never connect the AC supply from the power socket directly to your railway.

The Controller

hornby controllerThe track controller (also known as a speed controller) is another box – such as the one shown left which is the Hornby R8250 – but with dials and /or switches on it and is perhaps the most recognised aspect of railway electronics.

The dials and switches setting the direction and speed of the trains, changing the power as it flows between the transformer and track.

The thin wires are called layout wires and provide the link from the controller to the track and perhaps accessories. These wires are often black/white or blue and red.

Wiring Up The Layout

In beginners sets, the layout wires usually have some form of connecting clip that attaches the wires to the rails. It may be necessary to insert the wire into these clips (one wire per clip) and then connect the clip to the rails but that’s it.

So all that’s required is to assemble the track: attach the wires to the track and controller, possibly connect the controller and transformer and then plug in the mains lead and you can start to run your trains.

When attaching the layout wires to the controller, you come across sockets on the controller labelled ‘controlled’ and ‘uncontrolled’. For the track, use the one marked controlled which means it is managed via the dials/switches to set speed and direction. Uncontrolled is used for accessories and track items such as points.

In more advanced layouts, the wire can be soldered directly to the rails for a more permanent fixture or when you want to conceal the wiring under the board on which the track lays but for beginners to model railways, the clips are more than sufficient.

For the purpose of this article, I’ve focused on wiring an analogue controller to a single track section (probably an oval as per most starter kits) with just one set of wires from the track controller to the track. Wiring up more sophisticated layouts will be covered later.

That’s it for this first part, next time around I’ll take a look at some of more often used jargon in model railway electrics. In the meantime, if you have any questions ask in comment below.

> A final, personal, note: I spend a huge amount of time testing, photographing, writing and researching techniques for these articles and pay for all the running costs of MRE out of my own pocket. If you found this article useful you can support me by making a donation on my fund-raising page. Thanks and happy modelling, Andy.
Founder of ModelRailwayEngineer, Andy Leaning

Andy is a lifelong modeler, writer, and founder of He has been building model railways, dioramas, and miniatures for over 20 years. His passion for model making and railways began when he was a child, building his first layout at the age of seven.
Andy’s particular passion is making scenery and structures in 4mm scale, which he sells commercially. He is particularly interested in modelling the railways of South West England during the late Victorian/early Edwardian era, although he also enjoys making sci-fi and fantasy figures and dioramas. His website has won several awards, and he is a member of MERG (Model Railway Electronics Group) and the 009 Society.
When not making models, Andy lives in Surrey with his wife and teenage son. Other interests include history, science fiction, photography, and programming. Read more about Andy.

Afflliate disclosure:The links on this page may take you to carefully selected businesses, such as Hornby, Amazon, eBay and Scale Model Scenery, where you can purchase the product under affiliate programmes. This means I receive a small commission on any orders placed although the price you pay does not change. You can read my full affiliate policy here. I also sell my my own ready to use, pre-made and painted buildings and terrain features. browse the range.
  1. Just locked on to your site and am going through the various sections. One thing that I would like covered, not sure if you have already done this, is one to do with signaling. I’m like many modellers want to include signals. I design my layout, stations sidings etc., put down the track but then get confused when it comes to putting in signals, what goes where and what type, I don’t mean semaphore or coloured lights. I think this would be an excellent topic to cover so any help in this area would be greatly appreciated.

  2. Hi Andy, hope you can help me, I bought a Flying Scotsman loco and tender (ebay £50) it’s in great condition but it shorts out my 19 volt adaptor and wont run, it’s not caused any damage that I am aware of, I am new to M R what am I doing wrong or have I bought a bad train..?
    Regards Tom.

  3. Hi Andy, I’m not sure whether you would be willing to advise me on this. I have purchased a Hornby Dublo 2 rail Flying Scotsman with tender drive R398. At the same time I purchased another Flying Scotsman motorised tender. I wish to convert it to 3 rail and was wondering whether I could use the power of both tenders to run the loco and coaches. I had thought of wiring them in parallel. If you are willing any thoughts please. Jeff Collinson Tel: 01255 822350

    • Hi Jeffery, to be honest, I don’t know but I’ll ask around. I might be worth joining the Model Railway Engineer Builders community on Facebook and asking there. Go here and click on Join next to the group. Andy

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