Hi there,
I'm trying to wire a loop that goes around my railyard. I'm using a Digitrax AR1 for this reverse loop but I'm having problems. My train can enter the loop but it will short out when it exits the loop. I've watched a handful of videos and other online resources but nothing seems to work. I'm hoping someone here can help me or walk me through what I need to do as I'm still relatively new to the hobby.
For context:
My layout is DCC
I've isolated the loop with isolated rail joiners
Thanks
Tough to tell just what you have going on with the details you provided. A couple basic questions. Is your train shorter than the stretch of track you have wired up to the AR1? You did isolate it with 4 insulated rail joiners, correct?
Give us some more details. A sketch would be great - be sure to follow the instructions for how to post one. Hang in there through your initial moderation period.
Welcome to the forums!
Mike
BNSFWillMy train can enter the loop but it will short out when it exits the loop.
Can the train enter either end of the reverse loop, or just one way? If just one way, it could be you've got a connection to the reverse loop that is hooked up to the main track wiring. Check to be sure all the track connections in the reverse loop are only connected to the AR1 output.
You indicated that you have fully isolated the reverse loop.
It is possible that the reverse loop or the adjacent track is miswired. You need to to determine if any feeders are crossed or connected improperly. Any feeder inside the reverse loop needs to be connected to the output side of the AR. Any feeder outside the reverse loop needs to be connected to the main bus that feeds power to the input side of the AR.
The usual cause of a train entering a reverse loop without shorting but then shorting upon exit is that the polarities match when entering, but the polarities are mismatched when exiting, indicating a wiring fault. If the wiring checks out, then you need to check the settings on the AR1. It could be a timing issue.
Rich
Alton Junction
Is there a circuit breaker upstream from the reversing loop power? Some circuit breakers trip faster than the AR.
Henry
COB Potomac & Northern
Shenandoah Valley
Hello All,
A simple way to determine where the track polarity shifts is to take a car and mark one side red and the other side black.
Another option would be to mark one side with a "+" (plus) and the other with a "-" (minus).
You can do this with electrical tape or pieces of colored paper.
As long as you can determine which polarity (side) is which.
This will be your "test car".
Set the car on the tracks with the polarity of the wheels (color coding or plus "+", minus "-") matching the polarity of the track.
Typically Red "+" on the Right, Black "-" on the Left, when the locomotive is facing the forward direction of travel.
Push the car through all your track variations.
If at a point you find the track color coding is opposite the colors on the test car you have reached a "reversing section".
Run the car along until the colors match again. That is the end of the reversing section.
Now you know which specific tracks to double gap and power from the ARU.
Hope this helps.
"Uhh...I didn’t know it was 'impossible' I just made it work...sorry"
jjdamnitA simple way to determine where the track polarity shifts is to take a car and mark one side red and the other side black.
Absolutely true, but when you view things from underneath that layout, as you wire, it's easier to get L & R confused.
One of the worst moments for an anesthisiologist is to look over the "ether screen" and see the surgeon is operating on the wrong side. Even worse when it happens to be an appendectory. (yes ththe later really happend, but fortunately not to me)
BigDaddy...when you view things from underneath that layout, as you wire, it's easier to get L & R confused.
That's why most wiring mishaps occur..."Dyslexics 'Untie'!"
If you are running the test car in a previously undetected reverse polarity section, and you see that the "Red" "+" side of the car is over a "Black" "-" track feeder, that might be an indication of a problem.
The shielding colors of wires typically don't change, no matter what angle you view them from.
If all your wireing is correct, you can adjust the trip current on the AR1 useing the set screw. It might be set too high. What DCC system are you usuing? Joe
I've never been fond of the "test car" method. Too easy to get confused while running the test car around the layout unless the rails are also color coded in some manner. Better to get a blank sheet of paper and draw the track as two separately colored rails, for example red and blue. Now, you have a permanent visual record of where red meets blue and blue meets red, the point of reverse polarity.
But, in this case, that is not even the issue. If you take the OP's word for it, he already knows where that point of reverse polarity is located, and he has fully isolated the reverse loop. From the OP's description, it sounds like a balloon track running around the yard. So, his issue is likely either a miswired feeder or a faulty setting on the AR1.
Of course, there is always the possibility that everthing is operating properly, feeders and AR settings, but the entire train is longer than the reversing loop. So, is it? Try just running the locomotive through the reverse loop.
The fact that the locomotive does not short upon entering the reverse loop but does short upon exiting the reverse loop is typical of a malfunctioning reverse loop. One end of a reverse loop will always be in phase with the adjacent track, while the other end of the reverse loop will be out of phase with the adjacent track. Why? Because the reversing section itself will have its polarity flipped by the AR unless there is a miswired feeder or a faulty setting on the AR.
If the entrance to the reverse loop is in phase with the adjacent track from which the locomotive is entering the reverse loop, the AR won't even be triggered. The AR will only be trigged upon the locomotive's exit from the reverse loop, so that the polarity inside the reverse loop matches the polarity of the adjacent track to which the locomotive is exiting. Now, the original entry point to the reverse loop will have the mismatched polarity with the adjacent track from which the locomotive is entering the reverse loop. And the exit point will have the matched polarity. That's just how a reverse loop works. Turn the locomotive around and try to enter the reverse loop from the original exit point. What happens then?
wouldn't a miswired feeder always cause a short?
BNSFWillMy train can enter the loop but it will short out when it exits the loop
from either end? or is there only a problem at one end?
richhotrainOf course, there is always the possibility that everthing is operating properly, feeders and AR settings, but the entire train is longer than the reversing loop. So, is it?
good question
greg - Philadelphia & Reading / Reading
gregc wouldn't a miswired feeder always cause a short?
Lucky me, I have never miswired a reversing section (loop) of track. I am always careful to fully isolate the reversing section, keep the feeders in phase, and connect all feeders inside the reversing section to the output side of the AR. But, what happens if a pair of feeders inside the reversing section are inadvertently connected to the main bus feeding power to the input side of the AR? I don't have an answer for that form of miswiring.
Anyhow, I would just urge the OP to confirm that his wiring is correct.
gregc BNSFWill My train can enter the loop but it will short out when it exits the loop from either end? or is there only a problem at one end?
BNSFWill My train can enter the loop but it will short out when it exits the loop
richhotrain gregc BNSFWill My train can enter the loop but it will short out when it exits the loop from either end? or is there only a problem at one end?
gregc what if, as you suggested, there's a reverse section feeder wired to the mainline bus? there would be a permanent short whenever the AR attempted to reverse the polarity at one end but works fine at the other end
what if, as you suggested, there's a reverse section feeder wired to the mainline bus? there would be a permanent short whenever the AR attempted to reverse the polarity at one end but works fine at the other end
Lastspikemike Way easier to build a reversing section using the DPDT first and test it for correct operation before inserting the auto reverser in its place.
Way easier to build a reversing section using the DPDT first and test it for correct operation before inserting the auto reverser in its place.
If a reversing section is correctly gapped and wired, the auto reverser will work just fine IF the user takes into account the protocols associated with a particular auto reverser, including the settings for timing and current trip setting and the concern for mixing mechanical relays (e.g., the OP's Digitrax AR1) and solid state circuitry like a circuit breaker upstream. A DPDT takes none of that into account.
richhotrainExactly. Imagine a reverse loop with one set of feeders.
so ...
669
gregc richhotrain Exactly. Imagine a reverse loop with one set of feeders. so ... gregc BNSFWill My train can enter the loop but it will short out when it exits the loop from either end? or is there only a problem at one end?
richhotrain Exactly. Imagine a reverse loop with one set of feeders.
richhotrainImagine a reverse loop with one ... feeder ... wired to the main bus.
trying to get more info from the OP
richhotrainNow what DCC user does that?
Me.
richhotrainIf a reversing section is correctly gapped and wired, the auto reverser will work just fine IF the user takes into account the protocols associated with a particular auto reverser, including the settings for timing and current trip setting and the concern for mixing mechanical relays (e.g., the OP's Digitrax AR1) and solid state circuitry like a circuit breaker upstream
Yet people are often posting on here about their reversing section not workkng properly.
richhotrainA DPDT takes none of that into account.
Which can be a good thing. If it doesn't work with a DPDT switch, then you know there is a problem in the wiring. If it works with a DPDT swicth, but not the autoreverser, then the wiring is correct (as long as it's a heavy enough gauge) and you know to look at other possibilities.
The real proublem with auto reversers is they all behave diferently to varius situations. The AR1 is hard to set up right and speed of train will affect how well it works. The length of track dose not seem to be as important and metal whells on boxcars don't seem to trip it as long as train is moving fast enough.
rrebellThe AR1 is hard to set up right and speed of train will affect how well it works. The length of track dose not seem to be as important and metal whells on boxcars don't seem to trip it as long as train is moving fast enough.
that's not how an auto-reverser should work.
looks like the AR1 can be set to handle a train drawing 6A and would suggest the trip current needs to be higher. what if the booster can't supply 6A or a circuit breaker limits the current?
sounds like the AR1 needs to trip at a lower current by adjusting the Trip Current Adjuster (TTC), turn counter-clockwise. 2A would probably be more than enough
928
CSX Robert richhotrain Now what DCC user does that? Me.
richhotrain Now what DCC user does that?
I am not trying to brag when I say this, but I successfully set up a complex set of four reversing sections on a double mainline on my current layout in which four turnouts and four double slips are involved, all controlled by four ARs, without so much as a single failure. No DPDT involved.
CSX Robert If it doesn't work with a DPDT switch, then you know there is a problem in the wiring.
If it doesn't work with a DPDT switch, then you know there is a problem in the wiring.
BNSFWillI'm trying to wire a loop that goes around my railyard. I'm using a Digitrax AR1 for this reverse loop but I'm having problems. My train can enter the loop but it will short out when it exits the loop.
Have you tried it with just a single locomotive and no other train cars?
-Kevin
Living the dream.
Lastspikemike You can build as many reversing sections as you wish but it's hard to understand why you would.
You can build as many reversing sections as you wish but it's hard to understand why you would.
gregc richhotrain Imagine a reverse loop with one ... feeder ... wired to the main bus. your observation could explain the problem trying to get more info from the OP
richhotrain Imagine a reverse loop with one ... feeder ... wired to the main bus.
your observation could explain the problem
Lastspikemike richhotrain Lastspikemike You can build as many reversing sections as you wish but it's hard to understand why you would. It might be hard to understand if one is building a small, say, 4 x 8 layout, but on larger, more complex layouts it's not hard to understand at all. Think about a dogbone layout with two reversing sections, one on each end. Then think about a double mainline dogbone layout. Now, it's easy to understand why someone, like me, would have four reversing sections. Well, depends on your control and power systems. I can see the advantage to treating a full double track layout as two independent single track layouts. Then you'd have 6 sections to deal with. Only one section in each track would need to be a reversing section so it would be feasible with DCC to build your suggested layout of a twin track dogbone with only two reversing sections in fact. For DC you'd have better control with four reversing sections but strictly speaking it would not be necessary. A set of SPDT on off block power switches downstream from the DPDT block power connectors would achieve much the same operating options even in DC.
richhotrain Lastspikemike You can build as many reversing sections as you wish but it's hard to understand why you would. It might be hard to understand if one is building a small, say, 4 x 8 layout, but on larger, more complex layouts it's not hard to understand at all. Think about a dogbone layout with two reversing sections, one on each end. Then think about a double mainline dogbone layout. Now, it's easy to understand why someone, like me, would have four reversing sections.
It might be hard to understand if one is building a small, say, 4 x 8 layout, but on larger, more complex layouts it's not hard to understand at all. Think about a dogbone layout with two reversing sections, one on each end. Then think about a double mainline dogbone layout. Now, it's easy to understand why someone, like me, would have four reversing sections.
Well, depends on your control and power systems. I can see the advantage to treating a full double track layout as two independent single track layouts. Then you'd have 6 sections to deal with. Only one section in each track would need to be a reversing section so it would be feasible with DCC to build your suggested layout of a twin track dogbone with only two reversing sections in fact. For DC you'd have better control with four reversing sections but strictly speaking it would not be necessary. A set of SPDT on off block power switches downstream from the DPDT block power connectors would achieve much the same operating options even in DC.
My layout is not a suggested layout but rather an actual layout. The two reversing end loops connect to a 4-track complex in the middle of the layout in which the two mainlines run parallel to each other, forming four parallel tracks. All four tracks connext through a series of four turnouts and four double slips, permitting trains to change directions from any track.
Lots of luck wiring that up with two auto-reversers.
gregc rrebell The AR1 is hard to set up right and speed of train will affect how well it works. The length of track dose not seem to be as important and metal whells on boxcars don't seem to trip it as long as train is moving fast enough. that's not how an auto-reverser should work. looks like the AR1 can be set to handle a train drawing 6A and would suggest the trip current needs to be higher. what if the booster can't supply 6A or a circuit breaker limits the current? sounds like the AR1 needs to trip at a lower current by adjusting the Trip Current Adjuster (TTC), turn counter-clockwise. 2A would probably be more than enough 928
rrebell The AR1 is hard to set up right and speed of train will affect how well it works. The length of track dose not seem to be as important and metal whells on boxcars don't seem to trip it as long as train is moving fast enough.
In my experience, if the AR1 doesn't work no matter how you adjust it, it's because of an error in the wiring of the track / reverse loop. Maybe disconnect all wiring to the reverse loop, then try it make sure it isn't getting power somehow (like a track gap that has closed and is making a connection). Then connect two wires from the reverse loop to the AR1 outputs, and see if you can get it to work. Then add additional feeders and test after each change.