# Help needed, train stopped running



## Ckriley (11 mo ago)

Hello all, I am new to model trains, I will try and explain this the best I can. I was given a HO model train set, along with Atlas Twin electrical system. Last night I was able to get the locomotive running, using DC. I connected the switches using A.C. I went to test a different locomotive and now I can’t get either locomotive to operate. My switches continue to work but the trains will not move.
I have taken everything apart and rewired. I have switched out the transformer box to a different one, still nothing.
Could this be an issue with the locomotives?
As I’m typing this I’m thinking that even though the switches are operable there still might not be a charge flowing through the track. But could changing out the locomotive cause it to short? I guess I need to check conduction on the track.
appreciate any help, thanks in advance.

Photos included, blue and yellow locomotive was the second one that never worked.
Green worked really well. Now won’t budge.

thanks again


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## OilValleyRy (Oct 3, 2021)

Remove all locomotives, set throttle to full, check both the rails and the DC terminal screws for continuity. While you’re at it, check both the line & load side terminals (power in, power out) of the double track switch. The AC side works fine so ignore that. 
You want to use a multimeter that has a low voltage range setting; a pro electricians one (120/240 etc) isn’t what you’d want to use… and pricey anyway. A cheap $3 volt ohm acdc tester. They practically give them away at harbor freight stores.
I probably don’t need to say it but, don’t put one probe on an AC contact and the other on a DC contact.


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## vette-kid (May 2, 2020)

I would start with a multi meter and verify that your getting power out of that controller. Next I would get a modern power pack. It's possible that you just overloaded the power pack and the DC side is no longer working. DC controllers are cheap, even for a high quality one. 

Sent from my SM-G781U using Tapatalk


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## kilowatt62 (Aug 18, 2019)

“I guess I need to check conduction on the track.” Yes, exactly! 
Since you already swapped power packs, and still no power, I suspect one or both wires between the power pack and red buttoned direction controller (Atlas-twin) are bad. Or, the direction controller itself is faulting. 
Get that cheap multi meter thats been suggested and set it to a lower (12 to 20) dcv setting. Start checking for voltage, first at the power pack, then at the input terminals of the atlas unit, then both sets of its output terminals. Then on to where those wires connect to the tracks. 
At any point that you don’t get a reading, you’ve found the problem. 
If you have voltage all the way through. Further testing is obviously needed. 
Hit us up here again and any of us can, and will help you further. Good luck my man. 

KW62


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## Ckriley (11 mo ago)

OilValleyRy said:


> Remove all locomotives, set throttle to full, check both the rails and the DC terminal screws for continuity. While you’re at it, check both the line & load side terminals (power in, power out) of the double track switch. The AC side works fine so ignore that.
> You want to use a multimeter that has a low voltage range setting; a pro electricians one (120/240 etc) isn’t what you’d want to use… and pricey anyway. A cheap $3 volt ohm acdc tester. They practically give them away at harbor freight stores.
> I probably don’t need to say it but, don’t put one probe on an AC contact and the other on a DC contact.


Thank you very much!


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## Ckriley (11 mo ago)

vette-kid said:


> I would start with a multi meter and verify that your getting power out of that controller. Next I would get a modern power pack. It's possible that you just overloaded the power pack and the DC side is no longer working. DC controllers are cheap, even for a high quality one.
> 
> Sent from my SM-G781U using Tapatalk


Thank you very much!


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## Ckriley (11 mo ago)

kilowatt62 said:


> “I guess I need to check conduction on the track.” Yes, exactly!
> Since you already swapped power packs, and still no power, I suspect one or both wires between the power pack and red buttoned direction controller (Atlas-twin) are bad. Or, the direction controller itself is faulting.
> Get that cheap multi meter thats been suggested and set it to a lower (12 to 20) dcv setting. Start checking for voltage, first at the power pack, then at the input terminals of the atlas unit, then both sets of its output terminals. Then on to where those wires connect to the tracks.
> At any point that you don’t get a reading, you’ve found the problem.
> ...


Thank you very much! Will do!


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## MidwestMikeGT (Jan 4, 2021)

I wonder if you had also changed the track configuration. If you have what is called a "reverse loop" - where the track loops back onto itself, it will not work as each rail on the track carries a certain polarity (depending on the directional settings on the power pack). 

The train engines work by completing a circuit from the negative to the positive rails. 
If the rails loop back onto itself, the negative meets the positive and the motor will not run.

Would you mind posting a photo of your track layout? It might help diagnose the issue (if it is a reverse loop issue).

oh, btw, I did test my locomotive's functionality once by disconnecting all other sections from the terminal section (section where the power goes in) and simply placing my locomotive on that one and powered it up to see if it works.


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## J.Albert1949 (Feb 3, 2018)

Take two or three straight track sections, connect them together.

Set an engine on them, in the middle.

Disconnect the DC wires from the power pack.
Set the power pack at about 1/3-1/2 throttle.
Touch the wires to the rails.

Does the engine move?

If so, try the other engine.

Does that one move?

If so, the problem is in the track or wiring, and not the engines...


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## SF Gal (11 mo ago)

All great suggestions so I am curious what you found out, if anythng? 
If you get a chance, start a new member thread and tell us about the layout!


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## CTValleyRR (Jul 26, 2014)

I'm going to with Midwest Mike's solution: it sounds like you may have a reverse loop and power-routing turnouts. Aligning the turnouts in certain configurations causes a short.

I definitely think we need to see a track plan or photo.


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