How to wire up LED lights on your model railway – the simple guide

I’ve covered the mechanical aspects of making street lights before, this post, however, focuses on the electrical element of wiring LEDs for buildings such as offices and stations, street lights and even bonfires.

When most people think of lights they think of street and room lights. But Model railway builders aren’t so limited in their imagination.

There are so many uses for lights around a layout, from simulating the warm glow of a bonfire to houses and office lighting to illuminated neon shop windows and advertising signs LEDs and the smaller grain of wheat lights have a multitude of uses on model railway layouts.

Extra: If you’re still new to LEDs there’s a great summary on using them here.

But no matter what you use them for you’ll have the same challenge — how to power, wire and control them.

Assuming you’ve got your hands on some LEDs that you want to use around the layout the first question is how to power them.

Power supply for LED lights

If you just have one or two lights and will only use them occasionally batteries are probably the easiest option.

A standard 9volt battery will be more than capable and depending on use will last some time.

If you have a lot of lights or don’t fancy crawling around under the baseboard changing batteries a permanent mains fed supply is what you’ll need.

For this, you’ll need an adaptor that changes the juice coming out of the wall sockets to see something less harmful for a model railway, a 12v DC supply.

Note, as covered in a recent reader q&a on lights and controller terminals, you can’t use the 16v accessory terminals on your controller for this.

Instead, I use these to power my lights.

They’re actually power supplies for other household electronics but work a treat for railway lighting, they’re also cheap which keeps Mrs MRE happy.

(If you want to know more about AC and DC power and LEDs there’s a walkthrough in LEDMagazine).

Connecting them up

With the LEDs and power supply sorted you’re nearly ready to connect them up and test things out but before you do one other element is needed.

The electricity coming out of the battery or power adapter will be way too much for the tiny LEDs.

To change it down resistors will be needed.

There are lots of different versions available depending on the power source, how many LEDs you have and how much each one consumes.

Luckily there’s a handy calculator here.

Just type in the numbers required and it’ll spit out details of the resistors you need and even draw you a little diagram showing where to connect them taking care of the series and parallel question that often confuses beginners. There’s a handy guide if you’re unsure what values to use, just click on the ‘?’ next to each field on the calculator.

Make a note of the Ohm ratings of the resistors shown, jump over to eBay and search for ‘resistor x ohms’. Obviously, replace ‘x’ with the Ohm rating shown on the LED Calculator website.

Now all that remains is to solder wires from the power source to the resistors and then to the LED (remembering to solder the wires to the positive and negative connections of the LED) as shown in the diagram and try them out.

Assuming all works as expected, place them on your layout, in your buildings etc, turn on the power and watch it spring into life and light.

Control & Extra lighting effects

This article covers permanently-on lights. To turn them off, just pull the power plug. Alternatively, a placing switch after the power supply could be used for easier on and off-ability (that’s the technical name for it, honest!).

But with a few extra bits you can have your lights flickering or changing to give the illusion of flickering flames, traffic lights or even a welding effect for engine sheds and garages.

Take a look at the wonderful Train Tech range of lighting products that provide the electronics for these effects. They’re simple to wire up, come with the necessary LEDs and work with both DC and DCC layouts.

Once you’ve got the LED or grain of wheat lights working then it’s just a matter of placing them in your buildings or street lights.

Positioning them inside buildings is pretty straightforward but be sure to leave a gap between the lights and resistors and walls etc to allow any heat produced to be dissipated. Just tape them to the inside walls of your building and you’re done.

I touched on how to make street lights previously but if you prefer there is now a wide range of ready-made street lights for OO/HO covering all possible types of street lamp. See them here.

What you’ll need to get summary

• 12Volt DC power supply
• LED lights and resistors from eBay or a local electrical supply (Maplin etc). Use the calculator above to work which.
• Optionally, Train Tech lighting effect controller(s)
• Street lights

> 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.

Picture of house lighting on the Miniatur Wunderland Hamburg model railway.

Affiliate notice: If you plan to buy the products on this page or similiar, please use the links here. These will take you to carefully selected businesses, including Hornby, Rapid Online, Amazon, eBay, Scale Model Scenery and Element Games, through which you can buy products mentioned. These links are made under their affiliate schemes which means that although the price to you does not change I receive a small commission on the orders you place which helps me maintain this site and allows me to create more articles like this. Please see my disclaimer for more information. Thank you for your support, Andy.