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Model  Circuits



Electronic circuits modeling the gyrating warning light simulate either the "flash effect" on the observer or the movement of the light.

It is disappointing that more isn't done at local model railroading conventions in the way of locomotive lighting. It seems that all the light bulbs used end up as scenery effects, illuminating buildings, street lights, etc.

Mike Mangini, executive director of the Golden Gate Railroad Museum, described how he designed models of all the Pyle-National and Mars units. These operated in true mechanical form, producing realistic effects. The designs were used on O-guage. Mike made these units from items that were readily available at a hobby store. It was most interesting to see Mike illustrate these on the blackboard in the museum's warehouse this summer as we discussed these oscillating headlights.

There are circuits available which will produce all kinds of effects for the model railroad enthusiast. There are cicuit modules available for oscillating lights, strobe lights, ditch lights, flashers, beacons, and constant lighting. It is the choice of the modeler as to the route to pursue in this regard. Factors such as the type of power supply, and the need for miniaturization of circuitry come into play here.

I'm an HO modeler and get great results for either Mars or Gyralites in my models where appropriate. I originally used the old PFM alternating filament kits - only game in town circa 1985. Later, I found the units from Ibenlite - excellent rotating effect with the 1.5v bulb circuits. Unfortunately the Ibenlite founder became ill and closed up. Now, I'm using the units from Richmond Controls . Tiny units, very good effect.

Craig Zeni


I'm not into electronics what so ever. I'm a 'burn it in' type of modeler. I know what I want and just start working toward that end. My first Mars light was a mechanical thing that had a brass tube pivoted where the lite penetrated the nose door on a F-7. The back was on the perimeter of a wheel that was hooked to the front truck by a rubber band. Naturally the locomotive's speed increased/decreased the oscillation. It worked, but was not what I wanted.

I looked at other circuits until I came up with a combination of several, with the one published as being the one I liked.

After publication, I sold several units across the country. They all were installed and as far as I know, still are working.

I wish I could take the credit for the LED modification thing, but as I remember, one of my electronic friends mentioned that LEDs could be cut. So one thing lead to another and you see the end product.

Doug Brown - originator of Cir. 2


Doug recalls one photo excursion:

We are in Grand Junction this one evening. It is just before sundown. We see that this eastbound is getting ready to pull out of the yard so I park off property and walk down the street to where the train will cross. I'm standing at the crossing arms, just waiting, adjusting my camera for worsening sunlight, thinking the crew will not get the go ahead till after sundown and no light. When all of a sudden, the engineer(?) turns on the gyrating light! Between the shock of the intense light, it's movement, being startled, and I don't know what else, I nearly fell to the ground. I imagine the crew got a chuckle out of that. Thinking about it, It almost felt like a Star Trek tractor beam, only in reverse, had hit me. That light was intense!


One can build circuits or purchase ready made modules. Factors such as those mentioned above will determine the individuals choice. I have included a listing of suppliers of ready made units together with suppliers of components at the end of this section.


The following discussion deals with the building of light circuits from individual electronic parts:

Voltage regulation can be used to provide 1.5 volts for illumination.

I have found that Model Power/180 Smith St./Farmingdale, NY 11735, carries bulbs which can be effectively used for locomotive lighting. I have found that the colored bulbs: Nos. 153, 154, 155 fit into the Athearn headlight openings. The 152 clear bulbs do not seem to have the correct diameter. What one has to do is remove the colored paint from the bulbs using nail polish remover. Make sure that the bulbs are dry before inserting into locomotive. The nail polish remover will damage the finish on the locomotive.

One can also use the "angel hair" bulbs from Model Power (No. 145) but in this case, a sleeve of 3/32" aluminum tubing is necessary. The tubing can be cut with a tubing cutter and using a 1/16" drill bit - reamed out. A 3/32" drill bit is used to taper the end of the tube to form a reflector for the No. 145 bulb.

If it is desired to have a colored bulb, coating the bulb with the paint used for suncatchers works fine.

It has to be decided how you will power the lighting in the locomotive. You can use a voltage regulator setup to do this. An alternative is a battery.

Many circuits simulate the mechanical movement of the gyrating light beam. The main purpose of the beam was to flash at individuals to attract their attention. Single bulbs used for this purpose rely on a dim to bright cycle.

Fiber optics may be worth trying for various lighting effects. It may be possible to utilize these for ditch lights in N scale using a one bulb source. One can also explore the use of rotating effects. A counter circuit incorporating individual bulbs could be used or a on bulb source with a mechanical means to illuminate the individual fibers could be devised. An advantage of using fiber optics is to locate the light source in and ideal location inside the locomotive and route fibers to another area. Fiber optic strands enable one to make a lighting structure (oscillating light or beacon) which will exhibit motion effects.

On all fiber optics ends mushroom the ends to get a much brighter light. Do this on both ends and you will be very surprised. I know I have tried it.

Mushrooming involves taking a lit match and holding it close to the fiber optic end. By trial and error, you will know how far to hold it away from the optic and not cause it to catch fire. If it catches fire, usually the end is ruined because it is blackened. Cut it off and start over.

It really works. Two things, - don't catch the optics on fire and don't use something to flatten it out. Just let the heat mushroom it to the size you want. When you are done. hold one end toward your face and with the other end point it at the room light. You will be pleasantly surprised.

There is one other thing about fiber optics that I will mention. Don't bend the stuff to sharp or it will not work very good, if at all. The light will actually go through the stuff at the bend!

Doug Brown - originator of Cir. 2


One thing to remember in the following circuits is that electrolytic capacitors are made with a tolerance of 20%. Since we are dealing with timing circuits, the operational performance of each circuit will have to be checked. These are "experimental" circuits. Therefore, the user assumes responsibility.

Circuit Diagrams: