# DCC - two ovals, crossover and reversing loop issue



## Eusjim (Dec 16, 2014)

I am adding the reversing loop defined by Turnouts C and A. Where do I place isolation for the AR Sensor / Booster? I have labeled the turnouts. See attached crude sketch of layout. Has been about 10 years since I was last in the hobby and am just beginning to get the hang of DCC.
Thanks for the help.


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## wvgca (Jan 21, 2013)

isolation / plastic joiner would normally go on the A and C areas, just to the inside of the turnouts with as long as possible reversing section ..input from either ed, output to isolated section


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## DonR (Oct 18, 2012)

Yes, I agree with WVGCA that your insulating joiners should be at A and C.
But, I forget how Atlas routes power through their crossing.

Better test it with a volt/ohmeter.

Consider top to bottom route A and
Left to right route B.

Put a probe on Left rail of Route A. Put the
other probe on both left and right rails of
Route B.

Do the same with the Right rail of Route A.

If you get a reading on either, you'll want to
put insulating joiners at point E. Thus the
entire crossing trackage would be isolated
and powered thru the AR.

Don


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## ccmrc.la (Dec 8, 2014)

Right on the money d.r.


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## Eusjim (Dec 16, 2014)

*Thanks RE: DCC with two ovals, reverse loop, crossover*

Hello... Thanks for the great help. Spot on with what I was told at a Dallas train store at 5PM. I have not yet opened the Atlas 90 crossing, which was a hot tip. Is there a place where Atlas defines their products? I went to Atlas and found a link to a picture... no electricals. I don't want to open until i finish track work, as it could be that the angle is 60 rather than 90 degrees. 
I wonder if Atlas has a tech support line. 
Added additional definition of layout in bold and underlined below. 
*A to C turnouts passing through crossover B is 5 feet with turnouts isolated as recommended. The greater loop, A to B to C and back to A is 15 feet.*
Again, you guys were fast and great with my DCC question. Pleased to meet pros.


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## DonR (Oct 18, 2012)

Just to clarify:

I found an old Atlas brass crossing in my
junk box. The two routes are isolated from each other. 

When you stop to think, these crossings are
often used in a figure eight layout. Following the left rail of Route A around the
figure eight it became the right rail of Route B which maintains polarity. So
by design the two routes are isolated from each other.

When you look at the underside you can see where Atlas has used
a 'jumper' over the cross conductor.

Thus, insulated joiners need be used only at A and C.

Incidentally, no 'booster' is required for the isolated
section. The AR would take track power and it's
output would feed the isolated section.

Don


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## Eusjim (Dec 16, 2014)

Thanks Don


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