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A model number would help, and you can also Google it to find more info.


As far as the 555 timer goes, I don't see the connection with the traditional semaphore unless it was used to limit on-time for a smaller display layout that might leave the train setting on the activation device for extended periods.

However, on a larger loop it could be used to hold the RED indication for a longer period after a short train passed.


These are usually used with an under-track contactor or an insulated-rail.

This document shows typical hook-up instructions Lionel #159

But look up your particular model.




> Be aware that the #82 is larger Standard Gauge.


> The 7-light requires a two-position contactor or a relay to function properly.

MTH 7-light document



Something else you should be aware of if you have not seen these in person, you are working with three different sizes & two different gauges.

#82 is Standard Gauge, as mentioned

#15x versions are traditional O-gauge size

7-light MTH is a finer proportioned O-scale product




Last edited by Dtrainmaster

I have a traffic signal circuit using a 555 timer and a 4017 counter from a couple years ago. I got it off the internet, but had to modify it to get it to work properly. Not sure my schematic is the working model (don't remember if I updated it or not?). Might be something to play with anyway.


I have since gotten an Arduino which made the traffic lights much easier. That might also make your project easier? The traffic signal circuit I had was continuous (repetitive cycles), but maybe someone here would be able to make it a one shot device with minor modifications?  

Last edited by rtr12

My Arduino circuit and code was also for traffic lights. It greatly simplified the other method using a 555 & 4017 that I was fiddling with. That's all I have really fiddled with so far using an Arduino though. I have some other sensors for Arduino which I got to try and learn more, but have yet to attempt to do anything with them.


I have not tried it, but I think something similar to the traffic signal could be adapted to signaling with an input from some type of train position detector rather than just using timed sequencing for the lights. I think you could probably make it fairly simple or even more detailed either way, depending on input sensors, locations and quantities used.

HI rtr12


I am using the old fashion isolated track method, nothing fancy. No IR just the isolated track and DC relay to trigger the gates and banjo and other stuff.  If I could plug something in to that and have the flashing light that would be great. Or have a Arduino that acts as a dc relay and activates flashing lights when the train cross the isolated track.

Sorry, I thought you were talking about signals, like red, yellow, green when a train passed. I may have something for flashing lights around here somewhere? It seems like that is something I have fiddled with before when I was messing with the traffic lights. So, you have 2 lights and want them to alternately flash when a train passes your isolated rail?  

Originally Posted by nvocc5:

Hi rtr12


If you have a method for the traffic lights I would like to look at that as well. That is a few project down the road but if I need to get the part I can order them now. Since RS is more or less out of business you just can not go to them and get the parts that you are missing.

The traffic signals gunrunnerjohn posted are the same as mine. I will check to make sure. I believe that is the working model as well. I will look for the flasher this afternoon. The one Bobby Ogage posted it probably a good one from Dale H, but the picture of the schematic is missing?


I would recommend Digi-Key for your electronic parts. Very reasonable pricing and shipping. They also accept small quantity orders. I get the parts in a day or two via USPS.


Model Railroad and Misc Electronics Here's a good site for some learning, there are a lot of 555 timer circuits here and the ones I have tried have worked. Lots of good information on other things here as well. He also offers circuit boards for some of the projects he has listed.


Model Train Circuits There is an alternating flasher circuit here, among many other things of interest. I have not tried any of these circuits.


Simple LED Flasher Circuits I believe this is the one I was thinking of from my post yesterday, there is one using a 555 timer. I don't think I ever got around to trying it so far?


Here is the Arduino Traffic Signals. I don't have a wiring diagram, but It's really simple. I set it up and took some pictures. Here is the code, I will post the Arduino file and pictures below.


The resistors used on the Arduino breadboard are 330 ohm.


/*   Traffic_Signals

    Operates Red. Yellow & Green LED's as Traffic Signals

This example code is in the public domain.



// Pin 13 has an LED connected on most Arduino boards.

// give it a name:

int greenled = 8;

int yellowled = 9;

int redled = 10;


// the setup routine runs once when you press reset:

void setup() {    

// initialize the digital pin as an output.

  pinMode(greenled, OUTPUT);

  pinMode(yellowled, OUTPUT);

  pinMode(redled, OUTPUT);



// the loop routine runs over and over again forever:

void loop() {

  digitalWrite(redled, LOW);      // turn off red LED

  digitalWrite (yellowled, LOW); // turn off yellow LED

  digitalWrite(greenled, HIGH);  // turn on green LED (HIGH is the voltage level)

  delay(10000);          // green LED for 15 seconds

  digitalWrite(greenled, LOW);   // turn off green LED by making the voltage LOW

  digitalWrite(yellowled, HIGH); // turn on yellow LED

  delay(2500);          // wait 5 seconds

  digitalWrite(yellowled, LOW);  // turn off yellow LED

  digitalWrite(redled, HIGH);     // turn on red LED

  delay (10000);          // wait 15 secongs









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Last edited by rtr12

Dear gentleman


Thank you so much for all the information.


Bobby Ogage I have been talking to Dale H via e-mail. Here is the one who gave me the information on the wig wag circuit. But I still thank you for your time and look forward on your advise.


John I know I always can count on you to whip out scheme in no time, if you do not have we know we are all  in trouble. After studying it I have some question in regards to the values of the ohms and 12 VDC power supply.


rtr12 Wow that is a lot of information to study, thanks I will look it over. I like your Arduino Traffic Signals layout. Let study that as well. Thanks for the links for the electronics.



The power supply will probably be no more then 100ma to run this, it's basically lighting eight LED's and since they're parallel/serial, you'll have maybe 60-70ma for the LED's.  The rest of the circuit doesn't take much power at all.


The IN914 would be the standard axial lead one, and the 4017B would be the DIP package.


I'm not sure what cap you're asking about.


Here are the parts I used to make the traffic light circuit. I did this all on a bread board that I also got from Digi-Key.


Parts are all from Digi-Key, except the DC power supply which was from ebay and resistors were probably from Radio Shack. GRJ's power calculations would probably be plenty, I already had purchased a bunch of the 1 Amp power supplies on ebay.



Item         Digi-Key Part #

1N914 Diode         -  1N914FS-ND

4017B Counter      -  568-3080-5-ND

555 Timer         -  296-1411-5-ND

10uf CAP         -  P1187-ND

1MEG Trimmer Pot -  T93YB-1.0M-ND



Power Supply - AC/DC to DC Converter 1 Amp - From Ebay - Here's a link


The resistors used were all 1/4 watt.


I tried this again last night but it isn't working. My wife was talking to me the whole time so I probably have something missing or improperly connected. I will check it again later today. The 12 VAC note got me wondering, I'm sure that should be VDC. Will report back later. Arduino is definitely MUCH easier! 

Last edited by rtr12

That note is a typo. It is definitely VDC. Also, I'm guessing probably better left coming from the output of the 555? I will delete it and fix the schematic. It's working now. Once you get all the jumpers in the right place it works.


I found a drawing that I think was the original that started it all. I don't think I was ever able to get it to work and ended up with the posted one instead. Here is a link to it 


Two more questions for GRJ,


1.) It seems like on first power up both the Red and Yellow LEDs on the N/S lights come on. Turning the power supply down to 0 (not cycling power) and then back up to 12 VDC fixes the problem.


2.) On my working schematic of this I have a 100k resistor drawn in between the feed to the 1M pot and pin 14 on the 8017. This doesn't seem to make any difference in the operation of anything? 


Any ideas on these? I don't remember this from fiddling with this before?


Here's a revised drawing with parts list. 


Can you post the TinyCAD file for that one?


I suspect the counter is coming up with odd outputs, there is no reset with the circuit.  I'd tempted to connect a .1 uf cap to the supply and reset, and a 10K resistor from the same junction to ground.  That would give you a power-on reset.  I think if you left it run for a spell, that would all work itself out.


Don't know why you'd need the 100k.


Last edited by gunrunnerjohn
Originally Posted by gunrunnerjohn:

Can you post the TinyCAD file for that one?


I suspect the counter is coming up with odd outputs, there is no reset with the circuit.  I'd tempted to connect a .1 uf cap to the supply and reset, and a 10K resistor from the same junction to ground.  That would give you a power-on reset.  I think if you left it run for a spell, that would all work itself out.


Don't know why you'd need the 100k.


Certainly, here it is.


I will try letting it set for a while and then add the new cap and resistor and see what happens.


It was a couple of years ago I was fiddling with this and I have no idea what the 100k was there for? I don't remember the two N/S LEDs on start up either, it was all working before, or so I was thinking?




The 4017 has a quirk where it can power up in an "illegal" state which probably explains the unusual LED combination you describe.  As the datasheet says,


Automatic counter code correction is provided by an internal circuit: following any illegal
code the counter returns to a proper counting mode within 11 clock pulses.
So you can wait 11 pulses of the 555...or you can apply a power-on reset pulse as GRJ suggests to the reset pin of the 4017.

Breadboard I got was a Digi-Key part #438-1048-ND


Thank you stan2004, will give it a try. I thought 555 at first, then was thinking 4017, then was totally unsure as the 4017 reset pin was going to the negative side?


Ok, tried it and it works so far, if I got it right (no fire or smoke anyway). Of course it wasn't acting up when I went back to change things. Here's a revised diagram, if you see any mistakes please let me know. I had a ceramic cap that I used here, no idea where it came from, probably ebay? I just picked one from Digi-Key to add to the parts list.


Last edited by rtr12

The 4017 has a so-called "active high" reset which means you briefly apply a positive supply voltage level signal.  That's what GRJ's suggestion does.  When you initially apply power the capacitor is discharged so there's no voltage across it.  Hence the 4017 reset pin sees 12V and the chip resets (and clears any illegal states).  Then the capacitor starts charging via the resistor so the 4017 reset pin soon sees a low-voltage on its reset pin causing the chip to exit the reset condition, and it starts counting based on the clock pulses from the 555.


The 555 has a so-called "active low" reset which means you briefly apply a low level (i.e., ground) signal to reset it. So in you schematic, this pin is connected "high" and the 555 is never in the reset condition.


Typically, in schematic drawings, you indicate an active-low pin by either designating the pin name with a bar over it or by inserting a small circle on the schematic symbol of that pin:


ogr 555 active low reset


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The connection of the cap to the power was what threw me as the 555 reset was going to power and the 4017 was going to ground, but it seemed to be the 4017 that was acting up. Anyway, good learning experience.


After stan2004's post I went back and read the 4017 data sheet and his note about the counter getting mixed up was right on the front page. Not that I would have figured out the meaning of it all, had he not explained it prior to my reading it.


Also, I am taking it that you got the new schematic with the reset added and didn't post a revision to it, so I did get it right?



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