DCC Reverse Loop Questions

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Jethro80

New Member
Good Morning, My father and I are working on a layout together and we have some questions about a reverse loop on the layout. The reverse loop is highlighted in green on the attached photo. We are both novices in the hobby and appreciate any and all the help you guys can provide. Since the reverse loop has multiply entry points how would one isolate the loop? Also we planned on wiring in the Digitrax AR1 reverser (we are using the Digitrax Zephyr system) would that work in this situation, would we need anything else? Any other potential issues we will encounter with reverse loop and current configuration? Thanks in advance!
 

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JeffH

Well-Known Member
OK, I believe you have a relatively short section that can be controlled by the AR1. If you isolate the section higlighted in yellow, by insulating the joints in red, I believe you will be good to go.

But I'm not an expert, so hopefully some more people will stop by and have a look as well.
1669213515336.png


There may be a way to include the entire loop, but those turnouts that exit the loop at the 11:00 and 12:00 positions have me scratching my head.

If teh solution in yellow works on paper, the only issue you may have is if your train has lighted passenger cars. Since those cars pick up electricity from the tracks, they can cause a short way back at the end of the train. Usually, it's just teh locomotive that is of concern. Hope that all made sense.
 

Jethro80

New Member
OK, I believe you have a relatively short section that can be controlled by the AR1. If you isolate the section higlighted in yellow, by insulating the joints in red, I believe you will be good to go.

But I'm not an expert, so hopefully some more people will stop by and have a look as well.
View attachment 156516

There may be a way to include the entire loop, but those turnouts that exit the loop at the 11:00 and 12:00 positions have me scratching my head.

If teh solution in yellow works on paper, the only issue you may have is if your train has lighted passenger cars. Since those cars pick up electricity from the tracks, they can cause a short way back at the end of the train. Usually, it's just teh locomotive that is of concern. Hope that all made sense.
Hi Jeff, thanks for the reply! That makes sense, what if the cars have metal wheels would that create a short for the section of the train not in the isolated area?
 

dave1905

Well-Known Member
The yellow section is the reversing section, the rest of the green is just part of the loop and doesn't matter what type of wheels it has. If you unfold and untwist your plan you have one loop with two "sidings"/alternate routes and a reverse connection across the middle of the loop. The yellow portion is the only part of the reversing sections, everything else is one of the routes around the loop.
 

JeffH

Well-Known Member
Hi Jeff, thanks for the reply! That makes sense, what if the cars have metal wheels would that create a short for the section of the train not in the isolated area?


Chances are near 100% that even though the wheels are metal, the axle could be plastic, or the wheels are isolated from each other somehow. So they would not cause a problem. one wheel going across the insulated rail joint isn't going to create a short that is bad enough, or the duration isn't long enough, to cause issues. It's mostly when you have the front truck and the rear truck picking up on the conflicting electron flow over a longer period of time. Some passenger trains with lighted cars make that problem a lot worse.

Theoretically, if the train is moving fast enough, it will pass through the short before your system would even recognize the short it as a problem.
 

timlange3

Member
The key is your train (at least the maximum length between pickup wheels) length is less than the reversing section. If your engine is the only thing with electrical pickup wheels your reversing section only need be longer than the engine. If engine and caboose pickup power, then the reversing section needs to be the length of the entire train. This means the insulated gaps should be big enough so a metal wheel cannot touch both rails on either side of the gaps at the same time. If your insulated gap is made by a razor saw and will allow a metal wheel to touch both rails then the length of the section needs to be at least the entire train length.
 

Suzie

Member
If your trains are no longer than the yellow section between the two turnouts then you will have no problem at all. If they are longer then it will be well worth trying to make the yellow section at least as long as the longest train that will use the reverse loop. It could be possible to move the bottom left turnout further left, perhaps using a curved turnout, to gain a bit of extra length for the reversing section.
 




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