# DCC trouble



## [email protected] (Feb 5, 2014)

I just installed a crossover using two left hand and two right hand switches, my problem is that about every forth pass the hand held controller on my M R C ProdigyExpress displays S V D A and I no control over my train, I have to unplug the power pack and start over. I called the help line at M R C and they said I had an arc that was shorting out the hand held but thay could not tell me how to fix it. It ony does it on my inside track the out side track is ok. Can anybody help. I am 71 and just starting my new hobby. My train is HO.


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## NIMT (Jan 6, 2011)

What brand and model of switches are you using for your crossover?
Did you insulate any of the rails?
Are you using switch machines to control the switches?


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## [email protected] (Feb 5, 2014)

I am using atlas snap switches code 100 nickel silver, come to think of it I am using code 83 for my track, I wonder if this might be the problem. Although as I said befor I do not have a problem when the train is on the outside track, it is only when the train is on the inside track, and these two switches are back to back, if you know what I mean. 
I did not think I needed to insulate any rails when using DCC.
these are not electric switches.

___________L__L_____inside track___________-

____L_________________L_____outside track__


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## NIMT (Jan 6, 2011)

Bingo this is why I ask questions that I do!
You can *NOT* use snap switches like that, they will short out!
I would explain why they are giving you trouble but it's way too long of an explanation!
Just go get 4 Code 83 Custom line switches, not snap switches! 
You can run code 100 switches but they just won't line up with the rails on the 83 very nicely, they will have a speed bump effect! 
You can get 100 to 83 rail joiners but they are the pits to work with! :retard:

And a little note when you get a chance upgrade from the MRC DCC controller to a Digitrax controller you will be so much better off in the long run!


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## [email protected] (Feb 5, 2014)

Thanks, I live in a small town and the hobby shop knows very little about D C C. It's one o'clock in the morning here so think I will retire for the day, thanks again for the help.


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## NIMT (Jan 6, 2011)

If you run into any questions give a shoot my web site is at the bottom of these posts and has my contact info there.


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## timlange3 (Jan 16, 2013)

Why would Atlas Snap switches short out? They are not power routing turnouts and have insulated frogs. I would tell you to use a NMRA track gauge and check the width of all the suspect track. Also use the gauge to check your wheel spacing, especially metal wheelsets.

Per chance are you not aligning turnout points correctly before the train goes through the turnout?


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## DonR (Oct 18, 2012)

Tom

It do get frustrating at times.
So hang in there. You have a good bunch
of guys who have lived through it all ready
to help you.

What MRC is saying is that you are experiencing a short
circuit somehow triggered by the loco on the inside track.

Have you inspected the location where the 'event'
occurs to make certain there is no metal fragment,
stray joiner or some such that the weight of the loco
causes to short to the rails?

Sometimes it is helpful to get a very close up eye level look
at what is happening. Can you get down and very close to
the point where the 'event' happens? Run your loco extremely
slow, creep speed, and when the MRC reacts see what the
wheels are touching. Is a wheel over the rails diverging from the frog?
If the lighting is low enuf sometimes you can even see a tiny spark.

It is possible that a metal wheel is spanning the tiny insulator
between the two rails diverging from the Atlas plastic frog. It 
happens a lot on my Pecos, and my brother found it on his
Atlas. A simple solution is to use a tiny dab of clear finger
nail polish where the rails come together. Let it set good before
running on it. 

If the above does not resolve your problem,
it would be helpful to have some idea of the layout with the crossover
in it. Is it a simple double oval or are there more complicated 
curves involved. 

Don


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## [email protected] (Feb 5, 2014)

Don
I think I might have found my problem, I have a right hand curve, a short piece of straight track and then a left hand curve befor my switch. I noticed on the first right hand curve the front right wheel on the engine lifts up off the track and then it goes into the left hand curve and derails at the switch or creates the arc. The curves are 18" radius, and my engine is a BNSF "H2" Dash 9-44cw 9 1/2 inches long. I think maybe my curve is to sharp?
Tom


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## [email protected] (Feb 5, 2014)

I tried to attach a picture of my track layout, but I do not see it. I went to the gallery then upload and picked one from my files and attached it then filled out the rest of the fields and submit????


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## Southern (Nov 17, 2008)

I have a double crossover on the back of my layout that has four Atlas snap switches that work with my Digitrax DCC system. I have them all wired to the same switch. I have no DCC problems out of them just derails that are common to Atlas awitches. I hope to have them replaced with Peco turnouts soon.


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## DonR (Oct 18, 2012)

Tom

There are instructions for pic posting here on the Forum, and in
some threads, but sometimes they confuse.

Here's the easy way:

Write your post.

Scroll down Bemeath the panel of icons. 

You'll see 'manage attachments' click on it.

A new screen will appear. You'll see a list of 5 BROWSE.

Click on the top one: The picture folders of YOUR computer
will appear. Select the picture you want to post, and click OPEN
on your computer screen.

Repeat for as many pics as you want to post.

When done, Click on UPLOAD (there are 2, use the top one).
You will be returned to the post page.

The address for your pics will appear when you click SUBMIT REPLY
below the Icon panel.

---

It may be that S curve is more than the loco can manage.

Anyway, again, look closely at the exact point the wheel lifts.
Sometimes, you can solve this by pushing a scrap 'tie' under
the track ties at that point, effectively raising the rail that much.

Don


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