# ho double cross over wiring



## Russdeb7860 (Feb 23, 2014)

I need some help! I have a double cross over on my layout that is between two dog bones. So to explain when the train crosses over the double cross over it is on the same line running the opposite direction. I have (4) tortoise machines hooked up and operating. I can not get the train to cross over without a short. I have an AR! reversing board but am not sure if it will work. Anyone done this for DCC and had it work.

Thanks Russ


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## NIMT (Jan 6, 2011)

Have you done the isolating on the switch?


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## DonR (Oct 18, 2012)

If your layout has two dog bones you would need 2 reverse controllers,
in addition to the isolated sections noted by NIMT.

Might help if you could give us a picture of your actual
layout so we understand clearly how it is designed.

Most likely the location of the insulated joiners is a factor.

You can test your reverse loop controller with a multi meter.

Assuming you are using DCC:

Power the track. Set the meter on AC. Put the probes on your main track and
note whether you get - before the meter reading. Then put
the probes on the isolated loop. Note whether - or not. Then,
do a fast short across the loop rails. Did the meter change?
If so your reverse controller is working.

Don


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## Russdeb7860 (Feb 23, 2014)

Here is a picture of my layout. The highlighted area is one power district. I need to know if I need to isolate the crossover switch and will I need to isolate after the switch to another bus run. I already purchased the ar1's but can not figure out how to wire them. Switches work fine with the 4 tortoise machines. I have them wired in series so that one operation throws 2 switches. Thanks for the help.

Russ


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## NIMT (Jan 6, 2011)

What you have is a double reverse loop.
You need just need to break it with 2 AR1's to get it to work right.


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## Russdeb7860 (Feb 23, 2014)

So if I understand correct one half of the ar1 is attached to the main bus and then the out section would be used to power the areas that you indicated? The black line that is on my picture is where my two areas are separated in to districts. Does that still stay the same? Sorry for all the questions, this one is just a little out of my knowledge.

Thanks Russ


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## DonR (Oct 18, 2012)

Russ

You are correct. The input to the AR1 comes from a track buss, the output
powers the isolated section.

Since you have the 2 districts, it would seem to me that you would power
the left AR1 from that district's buss, and the right AR1 from that district's
buss.

Have you investigated the internal wiring of the turntable to determine whether
it is able to reverse polarity on it's own, or if you may need an addition reverse controller
for it? Some do not need it.

The rule is, if a locomotive can be turned around so it's going in the opposite
direction on the same track, you have a reverse loop and needs a controller.

Don


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## NIMT (Jan 6, 2011)

Yep what DonR said.


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## Russdeb7860 (Feb 23, 2014)

One more question. So the short section that the ar1 will now power will need to be taken off that district and isolated by the ar1. If so does that mean it has normal power through the ar1 when the switch is not operated and the train runs the normal course?

Thanks again for all the help

Russ


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## Russdeb7860 (Feb 23, 2014)

Ok one more. Does the switch need to be powered from a separate supply or can it be powered from that districts main bus. I did isolated the switch at all 4 ends.

Russ


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## NIMT (Jan 6, 2011)

First who made the crossover and what code rail is it?
Have you been trying to run the cross over with an AR1 and it shorts out?
You shouldn't need to isolate the incoming rails on the crossover, in fact you want the incoming rails powered and connected to the incoming rails, so that the entire switch is connected to either district 1 or 2.
Why 2 districts?
Are you running a DCC command station and a booster or some other power management device?

The Ar1's are powered off of the district that they are in, it doesn't have anything to do with the switch direction.


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## DonR (Oct 18, 2012)

Russdeb7860 said:


> One more question. So the short section that the ar1 will now power will need to be taken off that district and isolated by the ar1. If so does that mean it has normal power through the ar1 when the switch is not operated and the train runs the normal course?
> 
> Thanks again for all the help
> 
> Russ


Russ

The isolated section will always get it's power thru The Ar1 regardless of
how the turnouts are set.

Don


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## DonR (Oct 18, 2012)

Russdeb7860 said:


> Ok one more. Does the switch need to be powered from a separate supply or can it be powered from that districts main bus. I did isolated the switch at all 4 ends.
> 
> Russ


The turnout rails will be powered by the main buss of whatever district you have it in. It does not need any separate power. The insulated joiners will block power from getting to
the crossover rails, so you'll have to either remove the joiners or run drops to the
cross over tracks. Probably best to run the drops.

It's motors are powered by whatever you use to power the other turnout motors.

Don


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## Russdeb7860 (Feb 23, 2014)

I have multiple districts because of the size of the layout. I am running an NCE command station with boosters. I just tried to break it into 2 equal section with separate boosters. I have the switch powered from the district it is in. I can isolate the area that was for the ar1 and control it with the ar1. The power for the switch does come off the main bus wire. So the short section for the ar1 will be enough to change the polarity when the train crosses over? What happens when the train comes out of that section? Does the polarity change again once out of the ar1 powered section. Does the section need to be as long as my longest train?

Thanks Russ


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## Russdeb7860 (Feb 23, 2014)

I also wanted to let you know that the double crossover is a walthers dcc friendly turnout. It looks to me that it has all the gaps in the switch required for isolation. Here is a picture of the switch.


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## NIMT (Jan 6, 2011)

Make the AR1 section as long as the longest engine consist that you would ever run, like 4 to 6 engines long.
Everything will switch in and out of phase automatically (DCC doesn't switch polarity as there is no polarity to AC square wave  ) that is the whole point behind the AR1.


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## Russdeb7860 (Feb 23, 2014)

I think I got it. After looking at your drawing for the ar1's my question is wouldn't I need a total of 4 ar1's to cover both sides of the switch? From the drawing it looks like if the train crosses over on the side that the ar's are not on that it would not work? Thanks again you have been a real help. Once you let me know on this I will give it a try and let you know.

Thanks Russ


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## NIMT (Jan 6, 2011)

No your not putting in the AR1's for the crossover, the crossover is fine, you're putting in the AR1's because you have created 2 reverse loops. just follow the rails around, the rails cross from one side to the other and that creates the "phase" problem.


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## NIMT (Jan 6, 2011)

Maybe this will help you understand better.
Green rail A, Red rail B


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## DonR (Oct 18, 2012)

Russ

The AR1s do all of the matching automatically for your isolated
sections. They sense when your loco spans the insulated joiners
that the isolated section is not matching the main track. It instantly
reverses the phase and the loco continues on without pause. When
it reaches the next pair of insulated joiners the AR1 again senses
a mismatch and automatically rephases. 

You do not need one when a conflict as NIMT has shown does not
exist. They are only used when it's possible to turn a loco around
and go the opposite direction on the same track.

You can imagine how difficult this is on a DC layout. 
Just be glad you are DCC.

Don


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