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Problem with Reverse Loop

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Problem with Reverse Loop
Posted by trainwrek on Friday, April 10, 2015 4:45 PM

Hello guys.  I'm new here and looking help from all you guys who I can see from reading here you know a whole lot more about this than I do.  Can you give me some help sorting out an issue with my reverse loop? I have a small 4 X 8  N-Scale (DCC) layout. Recently upgraded from Bachmann E-Z Command system to NCE PowerCab.  Upgraded the wiring which is a bus panel for the main tracks (4 divisions) and a separate bus for the single reverse loop.  I have a problem now that my PowerCab powers up and immediately shuts down whenever the reverse module is connected.  It worked fine before the wiring upgrade, which involved just adding more track feeder wires and upgrading the bus wires from 20 ga to  16 ga.  Also put the reverse loop on a bus.  I replaced the Bachmann auto reverse loop mod with a Digitrax AR-1.  I've checked and rechecked all wiring for shorts countless times, and resolved all of that.  A DC powerpack works great over the entire layout (as long as I don't cross from main track to reverse loop). If I place a loco on the reverse loop it runs like a champ. So no apparent shorts anywhere.  But PowerCab will not remain powered up when the reverse loop is in the circuit, unless I disconnect the auto reverse mod, power up the PowerCab, and then connect the reverse loop mod, everytime I power up the layout. Had the same issue with the Bachmann reverse module also.  I sure hope you gurus can tell me what I'm missing here.  Thanks,

Trainwrek

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Posted by mlehman on Saturday, April 11, 2015 12:06 PM

You didn't say much about gaps. More info there may help. Also, describe how the reversing section is configured as far as the track arrangement.

 

Mike Lehman

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Posted by rrinker on Saturday, April 11, 2015 12:45 PM

 All feeds to that reverse loop must come from after the autoreverser, so if you have a bus running to the loop feeders, it needs to come from the output of the AR1. The input of the AR1 would connect to the bus that feeds the rest of the layout. And you need the proper gaps, if it's a diagonal that cuts across a basic oval, both rails of both diverging sides of both turnouts need gaps - 4 gaps total. All feeds between the gaps must come from the loop bus and not the main bus.

                                 --Randy


Modeling the Reading Railroad in the 1950's

 

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Posted by skagitrailbird on Saturday, April 11, 2015 12:45 PM

The separate power bus you mentioned must feed its power into the reversing module ONLY. The reverse loop track should get its power ONLY from the reversing module.

Be sure the reverse loop track is fully insulated from your remaining track--both rails at both the loop entry and exit points--that is four gaps. If it still does not work, there are crossed wires. Try switching the AR-1's out put wires and see what happens. (May we assume the loop track is long enough to accomodate your longest train?)

Roger Johnson
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Posted by richhotrain on Sunday, April 12, 2015 9:23 AM

I think that it has all been said in the first three replies, so I will only reiterate it all here.

A reverse loop (or reversing section) must be completely isolated from the rest of the layout by creating gaps or insulated rail joiners in the rails.

The auto-reverser must be powered on the input side from the main bus or from a sub-bus powered independently from the reversing section.

All feeder wires inside the reversing section must be connected to the output side of the auto-reverser.

No feeder wires from outside the reversing section can be connected to the auto-reverser.

No feeder wires from inside the reversing section can be connected to the main bus or sub-bus.

So, apparently, you have insufficient gaps, crossed feeder wires, or misconnected feeder wires.

Rich

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Posted by trainwrek on Monday, April 13, 2015 7:47 PM

I got the problem fixed! Reversed the 2 input wires from the main bus to the AR-1 and the short was eliminated.  Thanks everyone, for all your feedback.

Trainwrek

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Posted by richhotrain on Tuesday, April 14, 2015 7:42 PM

That's rather curious because it shouldn't matter which way the two wires from the main bus are connected to the input side of the AR-1. Flipping them should make no difference.

Rich

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Posted by rrinker on Tuesday, April 14, 2015 7:49 PM

 Yes, that is rather odd, since all the AR-1 is really doing is flipping the order of those connections as needed. Powering up with nothing across the reverse loop gaps, it won;t matter which way it's connected. When the first train enters the loop, either you "luck out" and it's already matching polarity, or the AR-1 flips connection. Then when you exit the loop, it flips again to match at the exit side.

 Now if the input and output lines were mixed up, that's a different story.

                  --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by trainwrek on Tuesday, April 14, 2015 10:42 PM

I completely agree. After all it is AC. But that is exactly  what I did and it is working now...Not sure what to think about this.  Any thoughts from you gurus?  I'm perplexed and expect to find a problem somewhere else related to it at some point. 

Trainwrek

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Posted by richhotrain on Wednesday, April 15, 2015 6:40 AM

rrinker

 Yes, that is rather odd, since all the AR-1 is really doing is flipping the order of those connections as needed. Powering up with nothing across the reverse loop gaps, it won;t matter which way it's connected. When the first train enters the loop, either you "luck out" and it's already matching polarity, or the AR-1 flips connection. Then when you exit the loop, it flips again to match at the exit side.

And, of course, it is more than luck.  Whenever you have a reversing section (or loop), once reverse polarity is encountered and corrected by the auto-reverser, the polarity will change once again after a train enters the reversing section from the opposite end.  As it exits the reversing section, the polarities will now be mismatched, causing the auto-reverser to flip the polarities once again.

Rich

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Posted by rrinker on Wednesday, April 15, 2015 6:52 AM

 Well, by 'luck' I mean if you happened to get it wired correctly, the very first time you entered the reversing section nothing would happen, because it would already match. After that it depends on which way the trains enter and exit. If you exit the diverging side and the next train enters the diverging side, it will have already been set correctly by the exiting train and again nothing happens, but if you always go the same way around, it will have to flip every time a train enters and leaves.

                        --Randy


Modeling the Reading Railroad in the 1950's

 

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Posted by MisterBeasley on Wednesday, April 15, 2015 8:43 AM

So, how has it been working?  Have you tested it, running trains in every direction over every possible path?

I'm concerned about your statement that you upgraded the track bus.  That was a good thing to do, of course, but you have to be careful because every wire gives Mr. Murphy another opportunity under your layout.  A wrong feeder to an industrial siding, for example, might not show up for a while until you run a switcher down there to pick up a box car.

It takes an iron man to play with a toy iron horse. 

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Posted by richhotrain on Wednesday, April 15, 2015 2:27 PM

trainwrek

I completely agree. After all it is AC. But that is exactly  what I did and it is working now...Not sure what to think about this.  Any thoughts from you gurus?  I'm perplexed and expect to find a problem somewhere else related to it at some point. 

 

If it works now where it didn't work before, whatever you did apparently fixed the problem.  Who knows, maybe one of the wires on the input side was not solidly connected.  That would do it.  Let us know if future problems develop.

Rich

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Posted by trainwrek on Thursday, April 16, 2015 12:20 PM

You guys were all over it.  I guess I spoke too soon.  I must have just run a train into and out of the reverse loop from one direction, because last night I attempted to enter and exit from the opposite end of the loop and hit an immediate shut down (short) every way I attempted it.  Checked everything, even checked to see if a cut lever on the locos might be dragging of the turnout frogs or something like that.  No luck.  No adjustment of the AR-1 resolved the problem, and another look at the wiring orientation and rail gaps in all the required places turned up nothing.  So I am at a total loss right now...  Totally odd how reversing 2 wires on the AR-1 input leads would suddenly allow a loco to enter from one end when it wouldn't before.  Somehow that must have fixed a local short, but something is preventing the AR-1 from tripping at all.  What is your take? The up side - maybe I've made a little progress; the down side - I still haven't gotten anywhere..

Trainwrek

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Posted by rrinker on Friday, April 17, 2015 7:11 AM

If reversing the two wires allowed a train to go in - that tells me you only have 1 rail gapped, or there are main line feeders connected to the loop. Can you post a track diagram and show where your gaps are?

                       --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Friday, April 17, 2015 7:36 AM

trainwrek

So I am at a total loss right now...  Totally odd how reversing 2 wires on the AR-1 input leads would suddenly allow a loco to enter from one end when it wouldn't before.  Somehow that must have fixed a local short, but something is preventing the AR-1 from tripping at all.  What is your take?  

It's not odd at all.  Flipping the two wires wasn't the issue.  The issue was that matched polarites occurred on the entry into the reversing section but mismatched polarities occurred upon exit out of the reversing section.  And, of course, entry and exit are defined by the direction of the locomotive.

As Randy just said, either your feeder wires are screwed up or your rail gaps are wrong.  Insufficient gaps or misplaced gaps will do it.  Feeder wires will either be crossed, sourced wrong, or connected in the wrong place.

How about posting a track diagram?

Rich

Edit Note:  Here is a repeat of my earlier reply.

A reverse loop (or reversing section) must be completely isolated from the rest of the layout by creating gaps or insulated rail joiners in the rails.

The auto-reverser must be powered on the input side from the main bus or from a sub-bus powered independently from the reversing section.

All feeder wires inside the reversing section must be connected to the output side of the auto-reverser.

No feeder wires from outside the reversing section can be connected to the auto-reverser.

No feeder wires from inside the reversing section can be connected to the main bus or sub-bus.

So, apparently, you have insufficient gaps, crossed feeder wires, or misconnected feeder wires.

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Posted by richhotrain on Friday, April 17, 2015 7:54 AM

Trainwrek, here are some further thoughts for you to consider.

1. Rail Gaps.  A reversing section must be completely isolated from the main layout.  That means that there must be sufficient rail gaps, and the gaps must be located in the proper places.  So, do you have sufficient gaps and are they appropriately placed?

2.  Feeder Wires.  The AR-1 is powered by a pair of feeder wires from the main bus so that power to the input side of the AR-1 is from outside the reversing section.  Any all feeders connected to track inside the reversing section must be connected on the other end at the output side of the AR-1. No feeders from track outside of the reversing section should be connected to the AR-1.  How many pairs of feeder wires are connected to track inside the reversing section?

3.  AR-1.  While not a likely culprit, it is always possible that the AR-1 is not adjusted correctly or that it is defective.  Once you confirm that the gaps and feeder wires are installed correctly, it will be time to hone in on the operation of the AR-1, but not before.

Rich

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Posted by trainwrek on Friday, April 17, 2015 4:40 PM

Randy, I will attempt to upload a track diagram.  This will be my first attempt so give me a little while to see if the file I have can be uploaded here.  Be right back to you. 

Ken

(Trainwrek)

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Posted by trainwrek on Saturday, April 18, 2015 1:36 PM
Rich, I am using email to reply because I can't figure out how to attach the file one the forum.  I have attached a copy of my layout map showing the rail isolators.  Keep in ind my earlier post in which I said I had used the Bachmann EZ Conmmand system with this layout without a hitch, before I added more feeders and upgraded the bus wires. So rails were already gapped and worked without a problem before.  There are now 11 sets of feeders to the reverse loop.  Loco will enter or exit the loop from the point where it intersects the mail (Div 2) and the front of the layout, but shorts where attempting to enter or exit from either of the 2 points in the rear.of the layout (switches 6/8 or 7/9)
I was thinking the AR-1 was not sensitive enough because a two loco consist was only drawing about .21 - .23 amps and the info sheet with the AR-2 says the lowest trip setting is about .25 amps.  I ran the consist through switches 6/8 and they stalled over the rail gap - one loco on each side (not surprising).  What was surprising was the system did NOT short out, but the lead loco still had the headlight on, the rear loco back-up light came on.  In other words they seemed to be showing opposite polarities.  I'm guessing the lead loco was pushed far enough to get past the gap before they stalled, but why no short if they were picking up opposing polarities?  They would not respond to any input but NO short.  PowerCab did not shut down!!  I'm thinking a short still exists back there some where but for the life of me I cannot find it  Really perplexed by the fact that the system did not short out and shut down.  My patience with it IS starting to short circuit, though. I will try to post this with the track diagram (attached) for the sake of everyone following this post.  Thanks for any ideas you can come up with.
Ken
 
I haven't figured out how to attach the track digram here on the forum.  If anyone can tell me in laymens terms I would appreciate it.
 
 
Attachments area

Trainwrek

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Posted by trainwrek on Saturday, April 18, 2015 4:21 PM

One last post before I put this thing to rest while I try to raplace my reserve of patience, which is completely depleted now.  I have run this layout wired just like it is now on another DCC system without these problems for over a year.  I just installed bus wires (and a few more track feeders) to improve the way trains run and more safely accomodate the more powerful NCE DCC system (PowerCab).  Wherever I put new track feeders I have checked and re-checked countless times to make sure the po;arity is consistent throughout.  It is. I've rechecked ALL the  wiring and it is still as it should be.  I've now disconnected feeders that I thought might be suspicious in any way.  No change.  Every wire on this layout is connected as it should be and every gap or insulator is where it should be (has been for almost 2 years).  But the AR-1 is simply not tripping, regardless of how it is adjusted.  I have reinstalled the old Bachmann EZ Command reverse module, and it is not tripping either.  I am abdolutely certain the reverse loop power distribution panel is wired correctly and isolated completely from the rest of the layout.  So I'm near the point after spending almost another entire day on this problem of relegating this layout to a static display.  That won't last long because I don't have the space for an 8'X10' museum piece.  I will either find a solution or dismantle and sell this thing, soon.  But now that I have vented a bit, I will think on it for another day or 2 (and await some breakthrough idea from one of you guru's).  Then I'll give it one more try before I start donating stuff.  One thought of clarification - the entire reverse loop is wire to separate power distribution panel, with bus wires to each of the track feeders.  The Input side of the AR-1 powers the reverse loop power distribution panel.  For what it's worth...

Trainwrek

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Posted by floridaflyer on Monday, April 20, 2015 8:08 PM

I would suggest that you reinstall the EZ command unit and the Bachman reversing unit. this would be your original setup except for the upgrade in wiring. If the system works there is a problem with either of the new units. If it doesn't work then the rewire is suspect. 

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Posted by trainwrek on Monday, April 20, 2015 8:18 PM

Thanks for the feedback. I did reinstall the Bachmann EZ Command and it didn't work either. So there is, I think, an issue somewhere with the wiring, OR, the Kato power routing turnout is the problem.   I'm skeptical about the turnout being the issue because, as I said before, I never had this problem with that switch when I was using the EZ Command system back before the wiring upgrade. Any of you guys want to come help search for the needle in a haystack (short in this layout)?

Trainwrek

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Posted by richhotrain on Monday, April 20, 2015 8:30 PM

I am afraid that, on the basis of your descriptions alone, we are all speculating as to the cause of the problem.  

If the gapping and wiring is correct, as you say, then it could be the AR-1, but that is doubtful since you mention that your old auto-reverser is not tripping either.  

If I read your initial post correctly, you added a separate bus for the reverse loop when you installed the AR-1.  Not sure why you added a separate bus unless you were trying to treat the reversing section as a separate power district.  Depending upon how that separate bus is wired, that could be your problem.

One last thought.  Do you have any solid state circuit breakers on the layout?  The AR-1 has a mechancal relay, and it is incompatible with solid state components like circuit breakers.  However, since the AR-1 is not tripping at all, that doesn't seem to be the problem.  Since the AR-1 is not detecting the mismatched polarities, it sure seems like a wiring issue, either the sub bus or the feeders.

Rich

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Posted by trainwrek on Monday, April 20, 2015 9:18 PM

To answer your question, my layout is Kato Unitrack. All original wiring was the basic Kato wiring system (all 20 ga) from the bus panel to the track feeders. In numerous places 3 track feeders were fed through a Kato 3 outlet splitter. The reverse loop (about 20 feet of track) was fed by a total of 3 feeders from one splitter.  So the EZ Command auto reverser output was wired directly to the one splitter that fed the entire reverse loop. Needless to say trains didn't run very smoothly, especially on the reverse loop.  When I upgraded to the 2 amp PowerCab I decided for the sake of better performance and safety to add 16 ga bus wires to the entire layout, and add approximately 15 more track feeders to the entire layout (6 of them to the reverse loop).  So I removed all the Kato wiring except for 6" track feeders (20 ga) and brought power from a bus panel via 16 ga bus wires. Now the reverse loop has 9 separate bus wires so I put them on a separate bus panel supplied by the AR-1.  Trains run perfectly around the entire layout.  But they enter and exit the reverse loop only from the "front end".  Entering or.exiting the opposite end (where the AR-1 has to trip) does not work. I hope that explanation  make some sense. 

Trainwrek

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Posted by Anonymous on Monday, April 20, 2015 9:50 PM

Hello Trainwreck,

EDIT: Skip to my next post, then come back and read this one.

First, you will be unable to post pictures to the forums until you have hit a certain minimum number of posts.  My workaround was to create a photobucket account and link the urls in my post, which others have done as well.

Second,

Pictures of the Auto-Reverser installed and the track plan, the location of your gaps indicated on track plan, and location of all feeders in the associated reversing section and feeders in neighboring track sections will be most helpful in diagnosing your problem.  Dont give up.  This can get frustrating at times, but a little deductive reasoning and detective work will win out in the end.

Third,

The Bachmann System worked before the wiring changes.  It now does not work, is that correct? 

You also stated that the NCE system would not start up until your auto reverser was removed from the circuit, which was temporarily corrected later by swapping the imput wires.  Your NCE system started up and you ran a locomotive though the section, but upon further testing you found that you had a short. 

QUESTION:

Did the NCE system restart after you moved the loco off of the short?

How many feeders in the reversing section? How long is the reversing section?

Also a note about auto reversers:  Your gaps must be EXACTLY parallel on both sides of the reverser for it to work.  A friend of mine has a HO scale layout that had that problem, which is corrected by moving the gaps.

 

Also a little tip, when installing new feeder wires, put a car on the track that has wheelsets painted to match the colors of your feeder wires (ex: RED wheel one side/ WHITE wheel opposite side) when you go to drop the feeders, match the colors. 

On my AR-1 I used the following wiring setup: from right to left with the terminal strip down Red-input, black-input, middle screw not used, red-output, black-output.

 I hope this helps.

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Posted by Anonymous on Monday, April 20, 2015 9:53 PM

trainwrek
The Input side of the AR-1 powers the reverse loop power distribution panel.

What do you mean by this?  While holding AR-1 in hand with the terminal strip pointed at your feet and the 5 terminal screws heads toward you, your two wires from the power source should attach to the AR-1 on the right side most 2 terminal screws.  The middle screw should have nothing.  The left side should go to only the feeders that are in the reversing section.

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Posted by rrinker on Tuesday, April 21, 2015 6:27 AM

 It sounds like you are saying that the trains can go around the looop one way, but not the other? The AR-1 has to trip at least once no matter which way you run around a reverse loop - if you enter the loop on the side that just happens to already match up, there's no tripping of the AR-1 and the train enters the loop, but if the polarity was matched on entry, it definitely will not on exiting, and the AR-1 would have to trip. So if you cna both enter and exit the loop in one direction without the AR-1 tripping at all, you most definitely have something not wired correctly or have gaps missing.

                  --Randy

 


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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Posted by richhotrain on Tuesday, April 21, 2015 6:31 AM

Just a follow up to Randy's comments.  With that mechanical relay, you can hear the AR-1 trip.  It is an audible click.

Rich

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Posted by trainwrek on Friday, April 24, 2015 9:27 AM

I want to make sure you guys that have been so eager to help know that I really appreciate it.  We will get this sorted out.  It has to be one of those things that is so obvious you just don't see it.  I haven't been able to work on it for a couple of days though 'cause things just get in the  way some times (chemo).  I'm back and going to start disconnecting one set of feeders at a time and checking the problem till I find where Murphy is hiding.  meanwhile, Rich, to answer your question, I do not have any circuit breakers, solid state or otherwise, installed.  Layout is so small and simple I didn't see the need for them, especially since the PowerCab has a pretty sensitive CB built in.  I'm thinking of installing a light bulb across the switch where the short keeps occurring to see if that will help.  Any thoughts on that?  I tend to agree that it seems to be a wiring issue, sub-bus or feeder (more likely a feeder).  But where... Anyway - I'm going after it now.

Trainwrek

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Posted by rrinker on Friday, April 24, 2015 6:46 PM

 Even if you just draw it on a piece of paper and take a picture, or make a crude drawing using Paint - please, post a track plan and we can probably get this figured out very quickly. All you need is a free account on one of the photo sites like Photobucket. Or just PM me, I'll give you my email and I can post the picture on my personal web site.

                       

                    --Randy


Modeling the Reading Railroad in the 1950's

 

Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.

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