I like the effect of glowing fireboxes in my large-scale locomotives. Some locomotives come with a firebox glow circuit already installed; most usually do not. There are several commercially available “fire flicker” or “electronic candle flame” circuits that can be used to drive incandescent bulbs or LEDs in the firebox, but none of these look realistic to me. I wanted the effect to look like the shimmering, red-orange glow of a roaring fire in a coal-fired locomotive. I decided to make my own. Here is what it looks like in a Bachmann Annie firebox:
[youtube]http://www.youtube.com/watch?feature=player_detailpage&v=Tk0Q2fK7yO4[/youtube]
I figured while I was at it, I might as well add the capability to provide constant voltage for classification lamps and locomotive cab interior lighting. I intentionally left out any capability to power the headlight since my locomotive headlights and reverse lights are powered directly from DCC controllers in my locomotives. If you need to power a headlight, you can simply tap into the constant voltage provided by the circuit.
This article will describe the circuit in sufficient detail to allow you to build identical copies or to modify it to meet your needs. The circuit uses inexpensive discrete components that are available from a wide variety of sources. Potential suppliers are included with the components parts list. I bought enough parts to build five identical circuits and the total cost was under forty dollars – less than eight dollars per locomotive. No special electronics skills are needed other than the ability to use a soldering iron.
http://www.rhyman.org/articles/auxiliary-lighting-circuit
Bob