# Wiring Help Please



## Rebskipper (Nov 17, 2012)

I have a layout that I believe I made much too complicated....has at least one reversing loop and probably there are more........could use some help if anyone can decipher the attached pdf file....

Getting shorts in several places when the tracks come back on themselves...

The PDF file attached is a native one of trackwork only (single line) without my current gap locations so as not to confuse the situation.

I think I have my gaps in the wrong places
I also have one Auto Reversing board and probably need more than one location

If anyone out there can give me some direction on this I would really appreciate it.

Thanks


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## Brakeman Jake (Mar 8, 2009)

You indeed have two sections of track that need auto reversing.It would be easier for anyone to explain if you had numbered your track sections but still,here it is....

First,the red coloured section is one that will need insulation at both ends (both tracks) right before it connects to the turnouts.

Then you have another one that links both sides of your inside oval section (that you have spurs attached to) that also needs insulation at both ends.

In theory,you'd need two reverse units,however,you could get away with one as long as your reverse sections aren't entered by two different trains at a time.


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## Rebskipper (Nov 17, 2012)

Thank You Brakeman Jake, i will give it a shot
regards
Howard


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## cv_acr (Oct 28, 2011)

Also, for the pink high line, I would gap the one end at the left side of the diagram AFTER the switch for the siding on the left, so that the siding is not part of the reversing section. That way you can have a train sitting on the side track while another one enters the opposite end of the reversing section. You never want two trains crossing the reversing section boundaries at opposite ends.

And as Jake points out, the second reversing section is the connecting track across the middle. You can include all the spurs off that track as part of the reversing circuit. Even if another engine is parked on one of those spurs while a train is moving into the section. (It's only a problem if trains are crossing the gaps and shorting both ends.)

One other question: at one corner there are tracks running off the edge of the drawing. Do these connect up at all? Because if they do, you're forming a wye and another reversing section.

Everything else is fine and unless you are using selective power-routing switches, which do require some special consideration, other gaps shouldn't be required if this is a DCC layout. If it's straight DC and you want to run more than one train, then a lot more gaps will be required to break it up into separate power blocks.

I took the liberty of marking up your diagram. The red gaps are absolutely required to isolate the reversing sections. If those tracks connect off the edge of the diagram, then the yellow gaps are also absolutely required as is a third reversing unit. If you at all ever plan to run more than one train (and this layout is actually fairly well designed to support that) then I would NOT use one unit to power multiple reversing sections because inevitably eventually you will two trains hitting different gaps into reversing sections at opposite polarities at the same time and short the layout. The green marks can be ignored if this layout is wired for DCC.

*Edit: I see in the "unmarked" version of the diagram those two tracks both stub end. No gaps are required at the yellow marks.


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## Rebskipper (Nov 17, 2012)

Hi Chris
Thank you for taking the time to help me out. I will incorporate the suggestions that you and Brakeman Jake gave me. As you noticed, the two areas top and bottom to the right do stub end for future expansion. I am wired for DCC with an NCE Power Pro system so I will follow your suggestions for that mode of wiriing.

Thank you again for helping a newbie.

Howard aka Rebskipper


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## Rebskipper (Nov 17, 2012)

Chris
I am just a little confused if you will please indulge me. I've attached the layout again showing two areas where I noticed the polarity either changes or remains the same across gaps. Do they effect where the gaps should go? for example in the place marked Area 1, I believe the polarity remains the same throughout the reversing loop but changes on the other side of the turnout that goes back to the main (marked polarity different). Would this change the location of the gap?
thank you
Howard


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## Brakeman Jake (Mar 8, 2009)

I understand most of the track is already installed...just cut gaps where indicated and these polarity differences should disappear like magic...unless there's some feature that your plan doesn't show.


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## cv_acr (Oct 28, 2011)

Howard:

You need gaps at the red spots. If you follow a train around the oval, the polarity at all of the green locations will always be the same. The only way any polarity changes are introduced is due to the reversing track that cuts across.

Look at it this way: If the reversing section is not there, all you have is a simple oval. That requires no special handling as there are no polarity changes. Introducing the reversing section introduces a way for trains to turn around, and also introduces a place where rails of opposite polarity will meet. So that's what needs to be isolated. 

Verify this by mentally running a train around the main oval, ignoring all other tracks. You'll see you can do this with no changes in polarity. That's our baseline. Now run the train across the reversing section and you'll hit a point where the polarity changes. That's the short we need to deal with.

The green gaps on the drawing only isolate the oval into separate blocks, if you were using analog DC cab control, which you're not. They are not needed for your setup. The polarity will stay the same across all of these.

The red gaps isolate the reversing section. The polarity will be the same at one end of the reversing section, and opposite at the other. Which end depends on the direction the reversing unit is set to. It works by detecting the short circuit when a train crosses the gaps with opposite polarity and reversed the polarity of the isolated section, so the the polarity on both sides of the gap is now the same.


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## Rebskipper (Nov 17, 2012)

Chris
I understand what you are saying but what confuses me is that if I look at a couple of the green gaps that I have marked as Areas 1 and 2 on the attached diagram, the polarity is different across them and it is the same across the red gaps. 

What is further complicating this is that somehow I have managed to mess up my NCE system which I have disconnected and sent back for repair so I've been measuring DC current just to look at the polarity differences around the layout. Is this confusing the situation?


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## cv_acr (Oct 28, 2011)

Rebskipper said:


> Chris
> I understand what you are saying but what confuses me is that if I look at a couple of the green gaps that I have marked as Areas 1 and 2 on the attached diagram, the polarity is different across them and it is the same across the red gaps.


But what I am saying is that if the layout is gapped and wired properly, that's NOT correct. The polarity should NOT be changing across any of the green gaps. That's just a simple oval. The track should be gapped at the red marks to isolate the reversing section.

The way you have it gapped right now, if you test it with a voltmeter or current tester you might find that the polarity is switching where you say; but that's not gapped or wired properly. The confusion is coming from the existing gaps not being correct.


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## Rebskipper (Nov 17, 2012)

OK, I understand; have to find out where I went wrong with the wiring.
I appreciate the guidance.
thanks
Howard


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## Brakeman Jake (Mar 8, 2009)

Very nice explanation indeed...I couldn't do better.If you still have a hard time understanding,then I have another idea...

First,as Chris said,ignore the green insulation spots.Since you're having DCC,you don't need them so don't let them confuse you.

Then,redraw your plan but this time draw both rails and use a different color for both.Start with your inside oval with let's say red for outer rail and black for inner one then expand your drawing to the rest of your layout without drawing the reversing sections (between the two sets of red pointers) as of yet.When completed,you'll find the your colors match all around your layout and that the polarity will remain constant everywhere.

Then,always keeping the color standard,try linking the reversing sections.You'll then see what we're seeing...polarity will have to alternate to match the polarity of the main track,wich remains constant.


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## Rebskipper (Nov 17, 2012)

*Just One More Time Please*

Chris
I know you must feel I am beating a dead horse, and I really appreciate your help but I am not seeing what you are.

I have attached a drawing after reversing the wires where my greens were acting like red's at the top of the image. The problem is that when I get to the other side of the layout-bottom right of the image, the red's you've indicated are acting green.

I think this is because I am not seeing the ovals as you are. There is an inner oval, true and that is green all the way around. And where it reverses and cuts across the table there is only one point where the polarity changes at the turnout on the top of the document, which i think is correct.

However, the outer track is really not an oval. It appears to be but what it is actually doing is coming back to the inner reversing track. So I see two reversing sections.

The two red gaps you marked in the lower right corner I have labeled as Acts Like Green because the polarity is the same across those two gaps. I have removed all feeders from that section to be sure I only have one lead to the track.

All the other greens and reds are as you described. Which leads me to believe that if this correct I can locate auto reversing leads on the inner right side reversing track and also on the dashed lines to the left where the overpass grades downward.

Again I do appreciate your help and hope you dont feel I am a total idiot but I am just not seeing the ovals as you describe them.

Howard


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## cv_acr (Oct 28, 2011)

Rebskipper said:


> I think this is because I am not seeing the ovals as you are. There is an inner oval, true and that is green all the way around. And where it reverses and cuts across the table there is only one point where the polarity changes at the turnout on the top of the document, which i think is correct.


Technically that's correct. If you just cut gaps at one end of the reversing track you eliminate the short in the track. (Note you can graphically show the polarity meeting anywhere along the reversing track.) HOWEVER *if you run a train across that gap, a short circuit is introduced* as opposite polarity currents meet each other inside the engine. That's why a longer section of track needs to be isolated. Once the train is inside the isolated section, you change the polarity of the isolated section, so that when the engine travels over the gaps, the polarity of those rails matches. That's why you need the longer isolated section with the gaps at both ends of the reversing track, to make this isolated section.

What the reversing unit actually does is when it sees the short when the engine crosses the gap, it instantly reverses the polarity of the isolated section. This way the polarity always matches *at the gaps the engine is crossing.*



> However, the outer track is really not an oval. It appears to be but what it is actually doing is coming back to the inner reversing track. So I see two reversing sections.


No, it's not a full oval, but if you eliminate the overpass line from the drawing, all of those outer tracks are parallel to the inner oval, and will be the same polarity. 

The overpass line (the track drawn in pink) introduces another reversing section to be handled, the same as above. One pair of gaps will eliminate the short circuit *as long as nothing crosses those gaps*, but that's boring so we cut another pair of gaps at the other end to isolate a reversing section.


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## Brakeman Jake (Mar 8, 2009)

I don't see anything wrong in your drawing...it shows what we're trying to have you to understand.Let's say you redraw your reversing sections but starting at this end,you'll have a polarity mismatch at the other end and that's how it is supposed to be.These sections will always match at one end or the other,never both.And it's the purpose of the reversing module...to allow to match your reversing section to match with the end your train is entering then switch polarity so that the other end matches when the train leaves the reversing section.

The reversing module detects the polarity mismatch and switches automatically (instantly) so you don't have to do it manually.What it does is go red/black then black/red as needed.May be someone has better words to explain..........


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## cv_acr (Oct 28, 2011)

Here's an image online that shows the exact situation you have, simplified by not having all the extra spurs and sidings:


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## Rebskipper (Nov 17, 2012)

Chris/Jake

You are both terrific, thank you. I have drawn out the layout with both rails showing as you suggested Jake (attached). I believe it is correct. Please take a look at it and let me know.

It shows I need only 2 areas to gap for the reversing areas. Chris, your drawing showed 4 areas. Am I correct in assuming that the other two areas which I have circled on the layout, can be gapped if I want to create independent blocks. And would this be the best way to go?

Does it matter where I put the autoreverse leads in the reversing sections?

thanks again Guys; I really appreciate it.

Howard


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## cv_acr (Oct 28, 2011)

Howard, yes. You've now identified correctly where the short circuits are that you need to handle. Now you need the other set of gaps to make an isolated block for the reversing section. Now you see how I ended up with the red gaps in their positions. The other end of ther reversing track MUST be gapped and you MUST create an independent block for the reversing section.

The entire block between the gaps will be powered by the auto-reversing circuit. The leads to the reverse circuit can come directly from the power pack or your main power bus wires providing power to the rest of the layout, or simply an adjacent track that is not part of a reversing section. Options one or two would be preferred over option three just in terms of good power transmission and best practices.


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## Rebskipper (Nov 17, 2012)

Thank you Chris and Thank you Jake for being so patient with me. Sometimes it takes a while for this Yank to get to the endzone, but eventually I get there.

I really do appreciate the help you have given me.

regards
Howard


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## broox (Apr 13, 2012)

Something else to consider, since you've got the basics undercontrol. 
I was reading last night that the reversing section must be longer than the longest powered stock that you will use. This includes if you're running 2 or 3 powered locos at the head of a long consist. And something I hadnt even thought of - lighted passenger cars, they'll have pickups on the trucks and could be deceptively long, and potentially cause a short.

The website that I read it on ( wiringfordcc.com , I think it was), expressed it a bit more better, but you get the idea. :thumbsup:


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## Rebskipper (Nov 17, 2012)

Excellent point Broox, I read the same thing. Much appreciated
Howard


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