# Track power theory



## Dcr_inc (Dec 14, 2015)

Hello,
I am experimenting with Arduinos and trains. I'm aware that there are hundreds of ideas and solutions already on the subject but, I believe I have a new area for the Arduino.

I want to control my O gauge track power with an Arduino and whatever MOSFET, or Triac I need to handle the current and voltage.

My questions are:
1.) what is the voltage that is on the track for running the engines? I know it's AC.
2.) what happens when the whistle button is pushed on the transformer, voltage, freq, AC/DC?
3.) what happens when the direction button is pushed?
4.) what happens when the bell button is pushed?
I realize the first answer is the train 1) wakes up 2) the train changes direction 3) the whistle sounds and finally 4) the bell rings.. I'm looking for what voltage, frequency, AC/DC output comes from the transformer to the track.

If you know of an existing Arduino sketch / setup for this, please direct me there..

Thanks,
Dave


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## DonR (Oct 18, 2012)

Dave

Surprised that one of the 3 rail guys have not answered your questions.

I do know that the track gets 60 cycle 0 to 14 or so AC volts. 
I tried reading the manual for a Lionel ZW transformer that has all of
those features but it was short on describing how it
controls the sounds or their voltages.

Surely one of the 0 gaugers will come in with the right answers.

Don


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## Dcr_inc (Dec 14, 2015)

patiently waiting !!!


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## Shdwdrgn (Dec 23, 2014)

Since other answers are coming slowly, I'll jump in with my *very* limited knowledge of 3-rail... My understanding is that every time the power is cut, the train reverses direction, so 3) would mean that the direction switch literally just cuts power momentarily. At least, that's how it worked when I was playing with 1950's equipment as a kid 

As an educated guess for 2 and 4, it would almost certainly be adding a DC component on top of the AC track voltage. You can easily remove the AC component from the rails by placing a capacitor across the inputs to your circuit, and that technology has been available for the past century.


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## Dcr_inc (Dec 14, 2015)

Any idea how they varie the voltage to control the speed of the locomotive? Is it by a rheostat or Triac or what?


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## gregc (Apr 25, 2015)

Dcr_inc said:


> Any idea how they varie the voltage to control the speed of the locomotive? Is it by a rheostat or Triac or what?


Lionel CW-80 Transformer General Description


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## Dcr_inc (Dec 14, 2015)

Thanks..
Now to play...


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## TomW2034 (Jun 2, 2015)

Dcr_inc said:


> Any idea how they varie the voltage to control the speed of the locomotive? Is it by a rheostat or Triac or what?


My original Lionel transformer from the 1950's was basically a VARIAC.

My understanding of the CW-80 is that it controls the train's speed by limiting current.

After accidentally damaging my original transformer beyond reasonable repair, I hooked an incandescent light dimmer to an old 14 VAC transformer fished out of my toy box. It worked very well.

Since those dimmers work by PWM, I cannot come up with a reason why it might hurt any of my equipment.

Tom


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## gregc (Apr 25, 2015)

TomW2034 said:


> Since those dimmers work by PWM, I cannot come up with a reason why it might hurt any of my equipment.


I thought light dimmers use SCR/TRIACs to modulate power to the device by shortening the AC waveform. I guess you can call this an early form of PWM by controlling the voltage that the triac turns on at.

I wonder if the sharp impulse of voltage could cause problems?


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## gunrunnerjohn (Nov 10, 2010)

Since many modern electronic transformers also use triacs and generate the same waveform, I doubt it's going to damage electronics.


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