Matthew explains LED lighting for your layout

First things first, those of you who couldn’t watch Arnie’s stunning new video last time, it’s here.

“Hi Al,

I have been absorbing all your modelling tips and now it’s time for me to give something back…

I am an electrician and have great experience in wiring up LEDs in models (remember my Thunderbirds Tracey Island?).

The easiest way to wire up LEDs is according to their power source & LED voltage rating.

Say for a 3V LED, and a 9V battery power supply, you wire up 3 LEDs in series: 3+3+3=9V.

Then if you need more than 3 LEDs in the model, you can connect 3 more 3V LEDs in series (or a series circuit), then connect this series circuit in parallel with the first series circuit.

This way you don’t need to do any calculations for adding resistors, or look up the resistor table to find the right one – less mathematics, less soldering. It’s got to be good, eh?

Because LEDs consume very little power, or in other words draw very little current, you can connect many series circuits of 3 x 3V LEDs in this fashion.

In my Thunderbirds Tracey Island model I connected:

4 x 1.5V AA batteries in parallel for a total 6V power supply.

Then I connected 4 x 1.5V LEDs in a series circuit.

I connected 10 of these series circuits to the batteries. 40 LEDs in total.

Once you have the circuits and the power supplies sorted out, you can add switches to control each circuit of 4, or more LEDs separately.

Before I used these LEDs in my model, I tested them vigorously.

I ran my 10 parallel legs of 4 x series LEDs off 6V battery power for 8 days continuously.

My conservative calculations estimated 3 days of running time, so they well exceeded my estimations.
Because these LEDs use very little power, they are awesome.

NOTE: Battery voltage is DC voltage. So, all of the above relates to DC circuits only.

Now, because everyone in the train modelling world uses 12V DC output from the power adapters.
I live in 240V AC land, so my power adapters are 240V AC input via 3 pin flat plugs, 12V DC output.
UK and Nth America will be different inputs but I think we all talk the 12V DC output language.

So, for a 12V DC circuit using bright 3V LEDs:

4 x 3V in series = 12V


8 x 1.5V LEDs in series = 12V

So, arrange your series circuits around your models, run a twin wire (+ and -) back to the power source for each series circuit.

Connect all your positives together, connect all your negatives together – no resistors required!
Then, you can decide how you want to switch them. Easy.

I have also wired LED interior lights in my VW transporter 9 seater.

I have estimated you could wire a house in LED lights and have them running for 1.5 days continuously off a 12 V DC battery. How good is that?

I am willing to help any modeller with composing circuits of any voltage, using any LEDs, with any amount of switches, in any layout, because you guys have given me so many good modelling tips so far.

Have a good day, Al!

BTW, I now design optical fibre networks. So as soon as Intel develops the optical micro processor, we will all stop warming up the planet with excessive amounts of heat dissipation from electrical devices. It will be all electrical supply to optical converters. If we transmit at visible wavelengths, then we don’t need an extra electrical device to convert the light source into a wavelength we can see…

Wouldn’t that be nice?

Our power bills will be a lot less.”

“Hi Al,

Thank you for the time and effort that you put into running your “Tips and How To” Site.

I wonder how Meany modellers throw away a great power supply for running their accessories each time they up grade their computers. The computers Power Supply. I run several.

Each power supply has mutable out lets in 3.3v, 5v &12v that I use to power up several bus-bars. The outlet wirers are colour coded to give you the voltages and the amperages of each supply.

I hope that this will help a little with recycling old computers.



“Hi Alastair,

I started this layout with my kids and taught them how to build this railroad as their skills increased. We didn’t have much room so I built it as a wall unit 10″ deep with shelves to store rolling stock when it was folded up against the wall. They used the 4 x 8 flat side to post their school work. All the wiring is in a 2 inch space between the railroad bed and the outside. Two support legs swung out as it was lowered down to operating condition. All the scenery is crushed screen wire tacked in place and covered with plaster. We never finished it as they went off to school and their jobs took them else ware. So it sits in the garage gathering dust. Sad.

I enjoy looking at all the layouts that you post. Really nice work.

All the best


That’s all this time, folks. Please do keep them coming.

And don’t forget the latest ‘ebay cheat sheet’. I think I get more emails on that on anything else, so thank you.



22 Responses to Matthew explains LED lighting for your layout

  1. Nice trackplan. New subject – here we have a Gantlet track, is it called Gauntlet track in your country?
    Thanks, Max

  2. Hi Al

    Very interesting information, and nice layout for continius operation.

    I am looking for fiber optic information, specially how to glue the fiber optic with the leds and dont loss bright intensity

    Thanks again for the bunch of information you give us.

    Cheers. Guillermo. from the Patagonia Argentina

  3. Interesting use of the leds, but if you connect 4 x 1.5v batteries in PARALLEL all you get is higher power at 1.5V, not 6V. They need to be in series.

  4. I also think the track plan is very good.

    Is this a 4 foot by 8 foot layout?

    Thank you.

    Bob F.

  5. Hi Mathew,
    interesting article. I found a little flaw though. Let me quote you: “4 x 1.5V AA batteries in parallel for a total 6V power supply.”

    You probably wanted to write “in series”.
    Paralleling batteries increases the current, but the voltage remains the same.

    Keep up the good work.
    Kitchener, Ontario, Canada

  6. I use the “old” phone P/S to power my LED’s on layout–with sw’s push buttons on the 117v side to conserve $$$—-this way there are several dioramas with different themes

  7. now-wish I had pursued my ambition as an electrician-wouldn’t have any problems understanding your article-but will keep as a reference-thanks for the info!!

  8. Harold “Get the layout cleaned up & RUN IT YOURSELF” I am 68 yrs young when I fireup my trains on my layout.I have inerloop with industries & a outer loop for FASTmail.I can play with it for hours.What a enjoyment.

  9. Thanks to everyone for your input and the pictures … very helpful information indeed.

    Thanks Al


    Tom N

  10. HI Harold

    I love to get instructions from you how to build this wall layout. Where are you located so if it is possible I would love the come out and see it. If it is close by Southern New Jersey very close to Philadelphia area.

  11. Matthew,
    There’s an error in the early part of your post “4 x 1.5 AA batteries in PARALLEL to give 6 volts.”
    The batteries need to be in SERIES to yield 6 volts.

    Thanks for the details. Very well written.
    –Ben Z

  12. grea layoutt

  13. Why would You want to run a bunch in series. When lights are in series and one burns out all the other will not light. (remember the old Christmas lights) If they a group of street lights or a house was lit in series it might be hard to find the bad light. In Parallel if one gose bad the good ones will still be working. Most all street light and House in real life are in Parallel even the new Christmas lights ar that way.. May God Bless
    73s Bill

  14. I’m glad that some others spotted the Parallel / Series mistake – I had stated to question my own knowledge !!

  15. Hi Mathew,
    Great article on LED’s, but I have one question, not being a ‘Sparky’ or wiring knowledgeable, it’s where you say -‘Then if you need more than 3 LEDs in the model, you can connect 3 more 3V LEDs in series (or a series circuit), then connect this series circuit in parallel with the first series circuit.’ How do you set up series to run in parallel with the first circuit? Thanks for your info.
    Tom. O.

  16. If possible, dimentions of your layout? Very interesting but it seems too complicated for a Ho scale if it’s 4×8. Thanks


  18. Harold, dont just let the layout sit there abandoned and unfinished, just because your boys have moved on. Get to it and have a go and finish it yourself!! You will have hours of fun doing it I’m sure.
    With regard to the LED information, I am an ex-electrician and I think a couple of circuit diagrams would not go amiss when trying to describe something like this.

  19. At Last an Easier way to Read how to Wire LED’s Safely . Thanks

  20. Al
    I just saw your recent post where Harold had pictures of his unfinished layout hanging in the garage. One of the last words of his story was ‘sad’. I am not looking at the layout through his eyes, but I would beg to differ. To me that layout, its ingenuity, detail, and story made my day.
    To all of us would-be modelers, half-done layouters, dream-track planners, etc. You, Al, your posts and all of your fellow contributors keep our blood flowing for model railroading (and modeling in general). Some of us who no longer have the means or the space or the time live vicariously off your posts. Those of us with fond memories of our childhood train sets that have long since disappeared; or those of us stuck in too small apartments, driving wheelchairs, bed ridden, halted by severe arthritis or otherwise unable to model just now, love what all of you are sharing.
    I, for one, look forward to each email and gain another nugget of wonderful information or inspiration. All the stories build on the corporate knowledge and we all can learn from the ideas, mistakes and Q&A. Each layout, big or small, new, or not-yet-finished tells the story of a dream. For some of us who will never again have a layout or hold a model locomotive or paint a scene, you keep our dreams alive. We may no longer be in our basements working on our tables or soldering wires, but we can still sketch out ideas on paper or in our minds of what could be someday. Keep up the great work, and God Bless.
    For Harold; that great looking layout may just be waiting for the next generation of grandkids, new neighbor child or the yet unknown modeler on Craigslist just looking for a started layout to build his or her dream on.

  21. this is for james! if will find out any photo finishers in your area call and ask if t5hey have and scraps of mat board. i do and i can get it free just go pick it up i went this past momday and picked up some large ones halfsize hope you can find some

  22. Better to connect a resistor in the circuit as it will give the LEDs a longer life. Depending on the colour od the LED. As the current drawn by LED varies with colour- there is a web site in the internet which gives the current drawn by each type of LED. Also another web site gives the circuit diagram and the resistor to be connected either in parallel or in series (“LED circuit resistance calculator”) depending on the way one wishes to connect the LEDs ( in the above the author chosen Parallel circuit) –

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