Oil Tank Beacon for your Model Railroad HO Scale DCC Layout

My wife purchased a Bachmann Oil Storage Tank with Light when I first got into the Model Railroading two years ago. The Oil Storage tank used a bimetal strip in the bulb to cause the light to flash much like a Christmas light. The result was disappointing, the beacon light would change flash rates based on the speed of the direct current locomotive as originally I powered the beacon of off the track. Later I powered the beacon light from the AC output on the transformer, even then the light on the oil tank would seemingly change the flash rate on its own, sometimes slowing down other times speeding up.

About a year after I originally setup my HO scale model railroad layout I decided to switch to DCC (Digital Command Control). I was reaching the limitations of what I can do with controlling the DC model trains on my layout using "Blocks" or electrical isolated sections of track. I wanted the ability to easily control several locomotives on the same track without having to flick a battery of switches to control current to different areas of the track sections. I went with a Digitrax Zephyr Basic Set, although you can purchase decoders (the microprocessor that controls each locomotive in a DCC layout) from different manufacturers I choose to make things simple and installed Digitrax decoders in my DC (Direct Current) locomotives.

The conversion of my layout from DC (Direct Current) to DCC (Digital Command Control) was pretty straight forward, all I had to do is replace my Walthers Life Like Direct Current transformer with the Digitrax Zephyr Command Station, then install decoders in my locomotives. The problem was that, without a booster, the Digitrax Zephyr can only provide 2.5 Amps to the track with limits how many DCC locomotives you can control at one time. I have a lot of lights that derive the power off of the rails with further limited the number of locomotives I could control at one time.

As a rule of thumb, LEDs (Light Emitting Diodes) consume far less power than incandescent light bulbs. So I replaced all of the incandescent lights with LEDs (with current limiting resistors) but what to do with the oil tank that has a incandescent light with a bimetal switch that makes it blink?

I wanted my LED blinker circuit for the oil tank beacon to be as simple as possible with very few components. I came across this interesting article that uses what is known as a transistor's negative resistance to create a blinker circuit, click HERE to read the article.

In order for the circuit to work from rail power I added a rectifier diode to convert the AC current on the track to DC which is needed for this circuit. The Digital Command Control signal on the track is square wave that swings from +14.25 volts to - 14.25 volts. The Digitrax Zephyr Command station modulates the voltage with a signal that the decoders in the locomotives translate to determine speed and direction. Warning: Build this circuit at your own risk! You need to have knowledge of basic electronics and electricity to proceed.

I am not responsible if:

1. You damage your Digital Command Control station
2. You damage the decoders in your model railroad locomotives-You damage your model railroad locomotives
3. The circuit causes the moon to go out of orbit (like in Space 1999).
4. A pothole shows up right in from of your driveway.
5. A black hole forms next to your model railroad layout.

Like always, I recommend bread boarding a circuit you are not familiar with before committing to perfboard. I soldered the components to a small piece of perfboard then hot glued the perfboard to the inside of the oil tank. I then ran two thin wires to a nearby rail for power. Because the voltage on the rail is always about 14.25 volts, this very simple circuit always flashes the beacon at a constant rate.

Here is a picture of the Oil Tank installed on my HO Scale DCC Layout

Below is a Video of the Oil Tank Beacon in Action!