Lighting A Model Railroad Structure
Interior illumination using side glow fiber optic filament
by Carol Culnan

This is my first attempt at using side glow fiber optics to light the interior of a structure on my layout.  This is an N scale (1:160) model about 8" long built from a Micron Art etched brass kit.

The thought is to use a section of 5mm solid core side glow fiber optic filament with one 5mm ultra bright white LED on the end directed straight into the 5mm solid core side glow fiber.  Then place the fiber / LED combination into the upper area inside the model out of view, and allow the light to fill the structure. 

The kit has hundreds of pieces which create many potential light leaks.  To solve this, I built the structure and then used a lot of electrical tape, epoxy and paint to fill the gaps. 


I purchased a few of your loose ultra bright white 5mm LEDs and a section of your 5mm solid core side glow fiber optic filament.   


I created two separate sections, putting one LED on opposite ends of the two individual sections to provide a more even light.  I then painted the end of the filament, the end that is opposite from the LED.  I first painted it white, to help 'reflect' the light back into the filament, and then over that I painted a layer of black to prevent light from leaking and causing a bright spot to appear on the inside of the model on the wall.  I could also have used a type of reflective material such as tin foil, held and covered with black electrical tape to block the light from escaping out the end. 



I did not solder it, rather I used 3 sections of a terminal strip at the end with the resistor.  I used a couple of insulated butt connectors for the other LED as not not to block any windows or short out the circuit should it touch the brass walls.  The final power source is 12 volts, however I did all my workbench testing with a 9 Volt battery.


I feel the project was a success!  The solid core side glow fiber optics definitely provides the even light with no hot spots. 


It shows off the Queen Anne windows well.  I did not use a reflector above the filament as I originally thought might be necessary, however I could see where in a smaller building it might be necessary.  I would also use the 3mm solid core side glow fiber in a smaller building.


Sweet Project Carol!
Thanks for delving into a new application of model lighting with fiber optics!
 Paul ~ The Fiber Optic Store

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