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Trouble-Shooting Assistance -- MTH DCS HO Problem.

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Trouble-Shooting Assistance -- MTH DCS HO Problem.
Posted by rallison on Friday, September 5, 2014 11:30 AM

Hi, folks -- I’m looking for assistance from users of MTH’s two-rail DCS (HO scale) – if there are any here! My apologies in advance for the long post, but bear with me:

 
After 40+ years away from the hobby, I am in the process of building out a 5x9 model railroad layout. To keep it simple (or so I thought) I’m using MTH’s Z-1000 power supply, DCS Commander, and two of their HO engines.  But I’m having two electrical problems, one of which is absolutely critical, and the other problematic. Help with either or both would be much appreciated.

The layout is fairly straightforward – outer & inner loops with a double crossover between, and a figure 8 inside them, with a small yard and a couple of spurs hanging off of it, and a pair of double crossovers (one to each of the loops). Crossing over to both loops enables changing a train’s direction, but it requires a reversing section--the only real complication, or so I thought. But it turns out I have two electical problems:

 

PROBLEM 1: Critical engine failure at insulated track joint (See linked pic at “FIG 1 – Engine Short Problem”)

 

Before completing the reverse loop portion of the figure 8, I laid down a portion of the track figure 8 track to confirm that the yard and spur arrangement would be satisfactory, and to test the function of the turnouts and motors, etc. I included the insulators between the (future) reversing portion and the regular section, and then temporarily hard-wired the portion of the (future) reversing section with jumpers to the regular track, ensuring correct polarity. I did not wire up any turnout or crossover frogs – they’re all stock/insulated.
 
During a test operating session a few weeks back, I had one engine running on the regularly-powered section of the figure 8, heading from upper left downstream though the 3-way Walthers/Shinohara turnout. I changed the engine direction (DCS Commander ‘DIR’ button) to stop the engine, intending to reverse back up one of the spurs. When the engine came to a halt, it had one of the wheels of the rear truck stopped on the insulated junction between the hard-wired track and the (matched polarity) temporarily hard-wired future reversing section. There was a spark at the wheel, and the engine died. It did NOT trigger the breaker built into the DCS Commander or the one in the Z-1000 power brick. Afterwards, the engine would not power up in either DCS or DC mode, the DCS Commander would not ‘see’ the engine when power was applied, and attempting to ‘add’ it again resulted in an ‘Er’ message. After contacting MTH, I sent it in for repair; they replaced the PS3 diesel board and returned it to me.

 

While waiting for the repair on that engine I used my second engine—CAREFULLY, so as not to stop with a wheel on the insulated joint again--on the same section of track, and all seemed well. But at some point a car derailed and hit an obstacle near the track, halting the engine with one truck completely on the regular track and one on the insulated (and temporarily hard-wired) section of track. Again, the engine went dark, though this time the DCS Commander’s breaker did trip before I had a chance to hit the ‘Emergency Stop’ button on the DCS. And again this second engine will not power up in DCS or DC mode, is not seen by and cannot be added via the DCS Commander (‘Er’ again). I assume its PS3 board is dead, but haven’t yet sent it back for repair.

 

I’ve checked and re-checked the turnout for polarity problems, voltage issues, or shorts--but found nothing. There must be some problem related to the juncture of the two sections of track that I am missing. Suggestions that allow me to preserve the layout (and ideally, the future reversing function) would be most welcome--or an explanation of what I missed/why that’s not possible. Thanks in advance for your replies…

 

PROBLEM 2: Engine/Auto-Reverse failure/engine power outage at DXO from figure 8 to outer loop.

 

After I received the first engine back from MTH, I completed the track sections for the rest of the figure 8, and added Bachmann’s Auto-Reversing unit (#44912) to the reversing section--thinking that it should prevent any shorts at the problem juncture. See linked pic at "FIG 2 -- Engine Auto-Reverse Problem" for the current track configuration.

 

I was able to run the engine successfully across the track juncture described above, in either direction. I found that the Bachmann auto-reverse unit works very well when I traverse the insulated joints to or from the reversing section, EXCEPT when using the double crossover shown at the upper right to transition from the figure 8 to the outer loop. It works fine as long as the engine enters the DXO from the outer loop.  But if the engine is transitioning from the figure 8 to the outer loop the engine loses power in the middle of the crossover. Gaaarrrrhhh!

 

THEN, to add injury to insult, another derailment stopped the repaired engine at the same point on the track as in Problem 1 above, and once again, it’s dead as a doornail. But a bit more expensive.

 

 Anyway, yikes!

 

So that’s three engine failures now, making the fix on that section of track absolutely critical. I really would appreciate any and all help troubleshooting the problem.
 
Assuming I can correct Problem 1, I suppose I can operate so as to avoid the auto-reverse/engine power problem (by always hitting the figure 8/outerloop DXO from the outer loop), but I also welcome any suggestions to eliminate Problem 2 and enable full operation in either direction.
 
Sorry for the long post, but I figured giving all that information up front might answer/head off a number of basic trouble-shooting questions.
 
Desperate, with thanks in advance…
 
R. Allison
Mars, PA

 

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Posted by peahrens on Saturday, September 6, 2014 8:15 AM

Rick, welcome to the forum, in any event.  Sorry you've not got a good analysis of your problems yet but it's less than 24 hrs and the weekend allows more time for many to peruse the forum so I hope you get the needed help, or a start on same, today.  I've got an NCE system with DCC Specialties auto reversers so I can't compute the MTH and Bachmann related issues, sorry.  And I'm not the best at analyzing reversing sections nested within complex track (mine are very simple).  I would just add confusion if I speculated about root causes and solutions.

But I do want to add encouragement.  Firstly, surely your track plan can be made workable; i.e., don't plan to tear it up.  Secondly, I'll bet someone here will engage on your issues who has the expertise to help troubleshoot these issues. Maybe you said, but have you got on the phone with an MTH tech person, emailing your track plan, and asked them to troubleshoot this with you.  Given you have their system and locos I'd think they would be able and willing to stepwise diagnose and troubleshoot the issues with you.  I've found that many MRR vendors have been as helpful as they can be.

Hang in there!

Paul

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Posted by rallison on Saturday, September 6, 2014 9:02 AM

Thank you, Paul. The forum has been a GREAT source of information for planning and executing my layout. I'm in this for the long haul, so (while I'm eager to figure out a solution) am happy for any replies I get, no matter the timing. I also appreciate your encouragement--I've sunk a good bit of time and money into this, so I don't want to grow frustrated with a couple of flaws that I hope can be worked out--it's very dispiriting when the PS3 boards fry/fail.

I haven't engaged MTH directly; I wasn't really aware they would offer that kind of guidance, but that would be ideal. (I've corresponded directly with one forum participant who has a good bit of experience with MTH, but no luck yet. And though my LHS sells a lot of MTH, they seem to frown on DCS itself, so I haven't gone to them for help.) So I will try MTH's service line, as you suggested. Thanks again!

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Posted by maxman on Saturday, September 6, 2014 11:03 AM

One thing that I see is that you have the gaps at that death-zone 3-way in the wrong location.  The gaps should never be at the point end of a turnout.  I would remove them and then install 6 insulators on the three pairs of rails leaving the 3-way.

 

You should check for phase across all suspect insulators.  Get a volt meter and set it to whatever scale allows you to read at least 20 volts.  Read from one side of the joiner to the other.  If you read a voltage, then you have a phase issue across the joint that will result in a short as the loco crosses.

Regarding the double cross-over how are you operating the turnouts?  Are all four sets of points moving at the same time?  You didn't say what code rail you are using, but down at the club we have a couple of code 100 Shinohara cross-overs and the only way we are able to get then to allow a loco to run all routes smoothly is to have all the points move at the same time.  I think I've read on this forum that others have the same issue.  I'm sure it has something to do with gapping beyond the gaps that are already installed in the assembly.  But no matter how we configure the thing with additional gaps or additional feeds, we either introduce a short or a dead spot unless all points move together.  Anyway, even the one individual who had a chance of sorting this out at our place never got it to work any other way.

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Posted by zstripe on Saturday, September 6, 2014 3:42 PM

Rick,

It might be a good idea to review this site that I will link to. It talks about wiring Walthers Shinohara 3-way/double crossovers, just to make sure they are wired properly before installing any reverse sections. Has diagrams, one of the best wiring sites around.

Good Luck!

Frank:

http://www.webring.org/l/rd?ring=modelrailroading;id=13;url=http%3A%2F%2Fwww%2Ewiringfordcc%2Ecom%2Fswitches_walthers%2Ehtm

 

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Posted by richhotrain on Saturday, September 6, 2014 5:51 PM

My wife and I are baby sitting for our grandkids tonight at our daughter's house, so I have only given this thread a quick read.

But, I will make three observations.

One, that "death zone" should not be such unless you crossed some feeders.

Two, the double crossover on the upper left is not a reversing section, so there should be no problem there.

Three, the double crossover on the upper right is a reversing section, so you will need a series of gaps to resolve the reverse polarity on the crossover routes.  It appears to me, at first glance, that you do not have sufficient feeders in all of the right places.

I will check in later when I get back home.

Rich

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Posted by rallison on Saturday, September 6, 2014 6:20 PM

Maxman -- thank you for your reply. I absolutly will move the gaps. I'm wondering, though: Would moving them the other direction, to the non-point side of the turnout controlling the spur on the reversing section, do the trick, too? For a variety of reasons, that location will be easier to modify, and I really don't run any long trains due to the small size of the layout... but please let me know what you think.

The digital voltmeter reads 0.00v to 0.01v across the insulated joint on either rail. Is 0.01v really enough to cause the problem? If so, is there an easy electical fix? (The Bachmann Auto Reverse unit is fed by the same power source as the other drops.)

The layout is Code 83. The Walthers/Shinohara DXO between the outer and inner loops uses manual Caboose Industries throws. The DXOs between the figure 8 and the outer and the inner loops will each be run by two switches (until I can afford Snappers) controlling either end of one crossover -- upper left and lower right are paired, lower left and upper right are paired. So I currently have two sets moving at the same time. But during my test operations all four turnouts on the DXO between the outer loop and the reversing section of the fig.8 8 were manually set for crossover in both directions. It's certainly possible that some combination of pickup wheels is hitting the dead XO frogs at the same time another set is hitting the dead turnout frogs, but it seems to me--without making my brain hurt too much--that then it would cause a problem in both directions; and per the pic it only occurs when going from the fig. 8 to the outer loop... but I will invest in at least one Snapper, I guess, and give it a try.

Again, thank you for your guidance--much appreciated!

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Posted by rallison on Saturday, September 6, 2014 6:27 PM

Frank -- Thank you for your reply, too. I'd read most of the material at that site while planning my layout, and did ensure I got the 'DCC Friendly' version of the Shinohara Code 83 3WT. I did not wire the frog, however, as I expected (perhaps incorrectly) that the signal issue that can trip up DCC on insulated frogs would not be a problem with DCS. Do you believe that it's worth re-wiring to juice/polarize/enliven (?) the frog? How would a dead frog lead to a short...?

If you folks think it makes sense to wire up the frog, I will use that diagram. Again, my thanks--I'm grateful for any and all assistance.

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Posted by rallison on Saturday, September 6, 2014 6:41 PM

Rich -- My thanks for your post. I have checked and double-checked my feeder polarity (both when I only had the jumpers in, before I completed the reversing section; and afterwards, with the Bachmann Auto Reversing unit) and am sure  the polarity is correct. That's exactly why I'm finding this so frustrating; while my experience is limited, I read up fairly thoroughly before starting the layout, and also ran my track/polarity plan it past folks in another forum before I put it together. Per my understanding of the plan, it should work. But clearly I've messed up or my understanding is incorrect.

I don't know if you saw the pictures I linked, but there are green dots shown where there are insulating joiners; so the DXO on the upper right is gapped between the 'x' and each of the turnouts that are in the reversing section. What additional gaps do you think it would need, if any?

I have fewer feeders than DCC would normally use--on the advice of another DCS users who tells me DCS does not like frequent feeders or power loops...

Your reply and any additional thoughts are welcome. 

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Posted by richhotrain on Saturday, September 6, 2014 9:57 PM

As I look at your track diagrams and re-read your initial post, a few questions come to mind.

One question relates to your turnouts.  Are the 3-way and the double crossovers all Walthers/Shinohara?  Code 83?

What about your RH and LH turnouts?  What brand are they?  Are the frogs all fully isolated?

My other question relates to all the gaps. Many seem unnecessary.

Also, the two gaps at the top of the diagram just to the left of the upper right double crossover.  Why is only one on each track?

Regarding the "death zone", I see no reason for a short unless you crossed feeders.  Also, you show only one pair of feeders to the reversing section from the auto-reverser. Is that the only pair of feeders inside the reversing section.

As I look at that second track diagram, it looks like you chose to isolate the bottom half of the double crossover on the right side of the track diagram as part of a reversing section.  On close examination, it appears that you have sufficiently gapped the reversing section with those additional gaps placed in the "death zone" and on the LH turnout on the left side of the track diagram.  

So, we are going to need more information to understand and diagnose why this is not working.

It could be misplaced or crossed feeders.  Or, it could be insufficient gaps, improperly placed gaps, or partially closed gaps.

Rich

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Posted by rallison on Sunday, September 7, 2014 5:33 AM
Rich, thanks again. To answer your questions:
 
The layout is code 83; it's all Atlas snap track except for the two curved turnouts at top left and top right, the 3-way, and the DXO at center/bottom, which are "DCC-Friendly" Walthers/Shinohara.
The frogs are all isolated.
 
The gaps:
--Four pairs of insulated gaps are there to isolate the reversing section.
--The two pairs at the upper left DXO isolate the inner loop from the spurs and yard, as I was advised to do as the latter are prone to derailments and shorts.
--The two pairs on the parallel spurs left of center near the top are for the engine house, and will allow me to power off either track when an engine is parked.
--The two gaps at center bottom are built in to the Wathers/Shinohara DXO, and the two odd ones at the top mirror those gaps on the opposite rail at the top. Granted, it's an odd arrangement; but, along with the built-in ones in the DXO at bottom, it prevents each of the outer and inner tracks from forming a complete uninterrupted electrical loop because I've been told that DCS engines do not like loops.
 
I've confirmed matching polarity with my voltmeter, and have checked and double checked my feeders. I agree there's no apparent reason for the shorts—that’s why I’m stumped!
Yes, that is the only pair of feeders in the reversing section. I used very few feeders because my understanding is that, for DCS on a small layout, only one per section is needed.
I’m happy to provide more information, though I’m not sure what else is important to tell.
 
Sorry for the slow responses, but as a newbie on this forum my posts have to go into moderation first…
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Posted by richhotrain on Sunday, September 7, 2014 6:06 AM

A new morning, a fresh look.

OK, I read your initial post for a third time.

My real concern is that the MTH Z-1000 did not cut power at the time of the short with its built-in circuit breaker.  If you are frying the circuit boards in the locos, that is the real problem.

As far as taking the route you described, from the upper left portion of the figure 8 down through the 3-way without the auto-reverser attached, there should not even be a short - - - unless you have crossed feeders somewhere.  In that Figure 1 diagram that you show, all of the rail polarities appear matched, so no short should occur.

Waiting at this point to hear back from you.

Rich

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Posted by rallison on Monday, September 8, 2014 7:59 AM

Rich --

 

Thanks for the follow-up reply. I've been replying to thread responders since late last week, but as I'm new to the forum my posts go into moderation, so (per the site) it can take "24 business hours" for my replies to appear. In any case:

There are breakers in the Z-1000 and in the DCS Commander unit. The Z-1000 breaker has never tripped; but the one in the DCS Commander has (in one or two instances). I'm told that it trips at 5A, but that it takes only 2A or so to fry the board. So, I'm thinking about adding 1.5A breakers between the power distribution block and the feeders to each of the track sections; my only hesitation (aside from $) is that they would trip unnecessarily when an engine is under load...

Again, I agree that the plan as built and as tested SHOULD work. But it sure seems like I'm going to have to chat with someone at MTH to figure it out, or find a local MRR expert to come over and have a look.

Thanks again,

-Rick

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Posted by richhotrain on Monday, September 8, 2014 9:56 AM

Rick, I think that the first thing you should do is contact MTH about the circuit breaker issue.

My understanding is that the Z-1000 has a 6 amp circuit breaker, and if that is accurate, that would explain its failure to trip before the DCS Commander trips at 5 amps.  But, if it only takes 2 amps to fry the loco board, you need some sort of additional protection.  I have read where you can place an in-line fuse on the positive wire on the Z-1000, and that ought to be something you discuss with MTH.

The other issue, of course, is why the layout is shorting in the first place.  It still seems to me that some feeder wires must be crossed based upon your track diagram.  And, not that this would cause shorts, but there seem to be way too many rail gaps, most of which are not necessary to isolate that single reversing section.

So, you have two critical issues to resolve here.

Rich

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Posted by NeO6874 on Monday, September 8, 2014 11:17 AM

I'm doing this in my head and trying to simplify it as much as possible (no picture tools here @ work, sorry).

You have TWO separate reversing loop possibilities shown.  Assuming the top of the image is North ... 

 - the first is heading Eastbound, you can take the turnout right, and pass southeast through the yard and under the trestle. As you're coming back around the curve (northwest), you end up going westbound on the outer track.

- the second is heading westbound on the outer track, you take the crossover LEFT, and end up going over the trestle and then out onto the center loop heading eastbound.

- (Both of these loops can also be traversed the other way)

To solve this, you only need to cut gaps in the crossovers along the north edge of the layout -- no gaps in the entire centre section are necessary.  What looks to be happening is that you're trying to set two (or even three?) sub-sections in that fig-8 section, and you're confusing the auto-reverser (or don't have it wired in at all).

 

Best way I've figured out how to check "is this a reversing loop" is to take two differently colored pens/markers and a printout of that section.  Pen 1 is the "outside" rail, and pen 2 is the "inside".  Trace the loop with both pens in turn, and cut gaps ONLY at the places they cross, except in cases where

- they're crossing at an X crossing (since that's insulated anyway)

- loops made from one leg of a turnout to the other leg of that same turnout - in which case, the gaps are ready-made at the ends of the through and diverging route already

- a turntable (which always gets a reverser, no questions asked, because I'm bad with remembering to throw a DPDT, or throw it when I don't need to).

-Dan

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Posted by richhotrain on Monday, September 8, 2014 4:44 PM

rallison

Rich --

 

Thanks for the follow-up reply. I've been replying to thread responders since late last week, but as I'm new to the forum my posts go into moderation, so (per the site) it can take "24 business hours" for my replies to appear. 

Fortunately, you are now off moderation as of this morning.  I had to re-read the entire thread just now to pick up your replies which only recently appeared although you wrote them much earlier.

Let's deal with the reversing section first.  There is only one, and it is at the location of the double crossover on the upper right.  The double crossover on the upper left is not a reversing section because all four turnouts making up the double crossover have matching polarities.  The double crossover at the bottom is not a reversing section for the same reason.  So, only the double crossover on the upper right is a reversing section.  You have correctly placed gaps on the divergent ends of the two lower turnouts on that DXO.   To completely isolate the reversing section, you have correctly placed gaps on the tail end of the 3-way and on the divergent end of the LH turnout on the left side of the figure 8.  Since the input side of the A-R unit is wired to the bus, and the output side of the A-R unit is wired only inside the reversing section, the reversing section should work without a short.  If it isn't working correctly, then something is wrong with the A-R unit.  Three questions.  One, are you sure that the gaps are completely open?  Two, is the entire train length shorter than the length of the reversing section?   Three, is there any simultaneous entering and exiting of the reversing section.

Now lets deal with the "death zone" issue.  The short is occurring at the location of the gaps on the tail of the 3-way turnout.  Because those gaps separate the reversing section from the non-reversing section, it seems clear at this point that the polarities are mismatched.  This could be caused by several factors.  One, the AR-unit may not be working properly; either it is faulty, or it is not reacting fast enough to the short.  Two, the gaps may need to be slightly staggered instead of directly parallel across from one another.  But, what bothers me is that you initially said that the short occurred before you wired up the AR-unit, correct?  If that is true, where did the figure 8 section get power beyond the tail of the 3-way turnout?

One last thing.  You don't need more gaps.  I was suggesting fewer gaps.  You shouldn't need any gaps on the other two double crossovers.  The gaps in the spurs are fine since they are there to cut off power.  Do you have uninterrupted power on both the outer oval and the inner oval with all of those gaps?    Apparently you do.

Rich

 

 

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Posted by rallison on Monday, September 8, 2014 5:50 PM

Dan -- thank you too, for your reply.

 

I'd originally expected to make the whole figure 8 a reversing section, but was advised that only a portion long enough to handle a train either direction from the upper-right/North-East DXO would be needed. I did do what you've suggested, but using a paint program instead of a highlighter on line art of my layout. If you look closely at FIG 2 linked in my original post, you'll see that, rather than red and black as with the two outer loops, yard, and spurs/engine house section, the reversing section is shown in purple and blue. The gaps at that NE DXO, and at the 3WT, and at the East lobe of the figure 8 where it meets the yard turnout are what isolates the reversing section. I can move the gaps 'inward' at either end of the reversing section, but not too far on the East end as it would require much shorter trains...

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Posted by maxman on Monday, September 8, 2014 6:04 PM

richhotrain
To completely isolate the reversing section, you have correctly placed gaps on the tail end of the 3-way

I am still of the opinion that the gaps at the three-way should be at the three frog end tracks, not at the point end.

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Posted by rallison on Monday, September 8, 2014 6:28 PM

richhotrain

 

 [...] Three questions.  One, are you sure that the gaps are completely open?  Two, is the entire train length shorter than the length of the reversing section?   Three, is there any simultaneous entering and exiting of the reversing section.

[...] But, what bothers me is that you initially said that the short occurred before you wired up the AR-unit, correct?  If that is true, where did the figure 8 section get power beyond the tail of the 3-way turnout?

[...] You shouldn't need any gaps on the other two double crossovers.  The gaps in the spurs are fine since they are there to cut off power.  Do you have uninterrupted power on both the outer oval and the inner oval with all of those gaps?  

Rich,

Re: your three questions--

1. Yes, as sure as I can be; as a newbie I used Atlas' nylon insulated rail joiners at the gaps.

2. Yes, at no point have I run a train in the reversing section that is longer than either portion East or West of the upper -right/Northeast DXO.

3. No, by the time I built and activated the reversing section I'd already fried one engine board; so I've never run two engines/trains on the reversing section.

 

Yes, when the first board turned to toast I had only a small portion of the reversing section in place; it was insulated at the bottom end of the 3WT in expectation of building out the rest, and temporarily hard-wired to match the polarity of the 3WT because it did not yet extend up to the NE DXO and so did not need to reverse. THAT's what's weird about it. The first engine ran just fine back and forth over that portion of track many times while I was testing the set-up of the 3WT and the spurs. Only when the engine stopped with one if its wheel sets ON the gap did it short (badly enough to fry the insulation off a wire inside the engine!). Before I completed the AR section, power was supplied to that small isolated portion by alligator clip jumpers wired from one of the yard ends to the isolated section, and was not reversing. Of course, after that first engine died I triple-checked that I had the polarity correct. Then, once the AR unit was installed and the rest of the reversing section put in place, the second engine ran back and forth successfully (per the green arrows, anyway) many times, often engaging the AR unit with no issues, before it shorted out at the 3WT/reversing juncture. After I got the first engine back again it did the same, working correctly for a couple of hours' run time, until it too shorted out at that point. Again, you can see why I'm stumped as to the cause...

 

The gaps on the NW/upper-left DXO are there to isolate the inner loop from the yard/spurs section; I agree they're not strictly needed, but I wanted to isolate the main sections of track (aside from the reversing section) in part because I planned to eventually be able to feed power to each section separately--so that somewhere down the line I could run DCS, DCC, and DC at will on any of the main sections of track, or set them up with ciruit breakers so a short on one track didn't take out the whole layout: Also: I didn't place the gaps on the DXO at S/bottom center; they are built in to the Walthers/Shinohara DXO track. Anyway--on the outer and inner loops there is one interruption on each rail; again, per advice I was given from a professional layout designer/builder with much MTH/DCS experience who told me that DCS engines do not like complete electrical loops.

 

I very much appreciate all the time you've taken to analyze my layout and try to troubleshoot my issues. 

 

At this stage I think I will relocate and/or stagger the gaps by the 3WT/reversing joint. Can't hurt as long as I'm not running big trains. I will also look into lower amperage circuit breakers or bulbs to prevent the engines from experiencing 5A for as long as it takes the DCS Commander breaker to trip. And at this point a call to MTH seems in order, as I have to talk to them about repairing both engines--hopefully under warranty, as pretty much everyone seems to agree that the design of the layout, if executed correctly, should NOT result in a short at the 'death zone'.

 

*Sigh*

 

Thanks again, everyone. I am so grateful for this forum as a resource, and for the kind of fellow hobbyists who are willing to share their expertise. Much, much appreciated.

 

- Rick

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Posted by richhotrain on Monday, September 8, 2014 7:11 PM

maxman

 I am still of the opinion that the gaps at the three-way should be at the three frog end tracks, not at the point end.

 

How would that make any difference?

Rich

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Posted by richhotrain on Monday, September 8, 2014 7:24 PM

rallison

Yes, when the first board turned to toast I had only a small portion of the reversing section in place; it was insulated at the bottom end of the 3WT in expectation of building out the rest, and temporarily hard-wired to match the polarity of the 3WT because it did not yet extend up to the NE DXO and so did not need to reverse. THAT's what's weird about it. The first engine ran just fine back and forth over that portion of track many times while I was testing the set-up of the 3WT and the spurs. Only when the engine stopped with one if its wheel sets ON the gap did it short (badly enough to fry the insulation off a wire inside the engine!). Before I completed the AR section, power was supplied to that small isolated portion by alligator clip jumpers wired from one of the yard ends to the isolated section, and was not reversing. Of course, after that first engine died I triple-checked that I had the polarity correct. Then, once the AR unit was installed and the rest of the reversing section put in place, the second engine ran back and forth successfully (per the green arrows, anyway) many times, often engaging the AR unit with no issues, before it shorted out at the 3WT/reversing juncture. After I got the first engine back again it did the same, working correctly for a couple of hours' run time, until it too shorted out at that point. Again, you can see why I'm stumped as to the cause...

 

I highlighted two sections of your response.  For what it's worth, I note that after running repeating over those gaps without a short, the loco eventually shorted, first with matching polarities and no A-R in place and later with the A-R in place.  So, that would seem to rule out the A-R as the culprit since shorts occurred without the A-R in place.  

This is a shot in the dark, but the only commonality here is the 3-way turnout.  So, how about this.  Remove the 3-way and install a short section of straight track in its place with the insulated gaps in place and then see if the loco shorts out.  If it does, grab it off the layout right away before you fry the board.  

Beyond that, I am stumped.

Rich

Alton Junction

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Posted by rallison on Monday, September 8, 2014 8:13 PM

Rich, thanks again. I agree the Bachmann AR is not the likely cause, as problems occured when the partial section was hard-wired. I may try your suggestion about pulling the 3-way to see if that changes things, or move the insulators from that juncture a bit further East, to the other end of that curve between the 3WT and the next turnout counter-clockwise...

 

Speaking of which: I am starting to wonder if there might be a short or other problem with the turnout at the lone spur toward the bottom of the East lobe of the figure 8--given that in both scenarios--both before and after the AR installation--power on the curve that meets up with the lower end of the 3WT passed through that section... do Atlas code 83 540/541 turnouts have known issues of that type? I did have to take one back to the LHS due to a complete short, fresh out of the package; luckily discovered before it was added to the layout... could this one have an intermittent short? Has anyone seen anything like that with the 540/541 turnouts?

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Posted by richhotrain on Monday, September 8, 2014 8:38 PM

rallison

I am starting to wonder if there might be a short or other problem with the turnout at the lone spur toward the bottom of the East lobe of the figure 8--given that in both scenarios--both before and after the AR installation--power on the curve that meets up with the lower end of the 3WT passed through that section... do Atlas code 83 540/541 turnouts have known issues of that type? I did have to take one back to the LHS due to a complete short, fresh out of the package; luckily discovered before it was added to the layout... could this one have an intermittent short? Has anyone seen anything like that with the 540/541 turnouts?

 

Well, the fact that the loco is shorting when a wheelset is stopped right on the gaps makes the 3-way suspect since everything else seems to be in order.

Just out of curiosity, that turnout that shorted fresh out of the package, where on the turnout was the short occurring and what caused the short?

Rich

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Posted by maxman on Monday, September 8, 2014 8:43 PM

How would that make a difference?  (I wish I could have quoted entire post, but somehow the quote thing has suddenly changed format)

I have always been told that turnouts should be fed from the point end, and gaps should be at the frog end.  In this case, if I am understanding the diagram correctly, there is no power feed to the points.  So the points are being backfed by the pair of feeders beyond the 3-way.  I asked previously if that 3-way was a code 100 or a dcc friendly code 83.  That question was ignored.  If the 3-way is not dcc friendly, who knows what effect that might have at the point end.

It was my understanding that feeding from the point end was always good practice, no matter dc or dcc.

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Posted by rallison on Monday, September 8, 2014 8:47 PM

The short on the unused turnout was complete, left rail to right rail on the straight route. No apparent cause--it looked normal underneath, etc., but there was zero resistance when tested with the voltmeter, one probe on each rail...

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Posted by richhotrain on Monday, September 8, 2014 8:55 PM

maxman

How would that make a difference?  (I wish I could have quoted entire post, but somehow the quote thing has suddenly changed format)

I have always been told that turnouts should be fed from the point end, and gaps should be at the frog end.  In this case, if I am understanding the diagram correctly, there is no power feed to the points.  So the points are being backfed by the pair of feeders beyond the 3-way.  I asked previously if that 3-way was a code 100 or a dcc friendly code 83.  That question was ignored.  If the 3-way is not dcc friendly, who knows what effect that might have at the point end.

It was my understanding that feeding from the point end was always good practice, no matter dc or dcc.

 

The OP wasn't ignoring your question. His posts were being moderated, so they took over 24 hours to appear. 

The 3-way turnout is a DCC Friendly Code 83.   Read back through the thread and you will see his replies.

Rich

Alton Junction

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Posted by richhotrain on Monday, September 8, 2014 8:57 PM

rallison

The short on the unused turnout was complete, left rail to right rail on the straight route. No apparent cause--it looked normal underneath, etc., but there was zero resistance when tested with the voltmeter, one probe on each rail...

 

Hmm, I suppose that Atlas turnout that you mentioned could be faulty.  Pull it out as well and replace it with a regular section of track for testing purposes.

Rich

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Posted by rallison on Monday, September 8, 2014 9:31 PM

Maxman -- apologies if it seemed like your reply was ignored. As a newb, my posts were sitting in moderation queue all weekend. But if you look above you'll see I replied to you on Saturday, September 06, 2014 6:20 PM. As noted above, the 3WT is an unmodified 'DCC-Friendly" Walthers Shinohara code 83. I gather I'm no longer filtered through the mod queue.

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Posted by rallison on Monday, September 8, 2014 9:33 PM

Thanks again -- off to catch some zzzzzz... and to think on all the suggestions. 

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Posted by richhotrain on Tuesday, September 9, 2014 4:43 AM

maxman

I have always been told that turnouts should be fed from the point end, and gaps should be at the frog end.  In this case, if I am understanding the diagram correctly, there is no power feed to the points.  So the points are being backfed by the pair of feeders beyond the 3-way.  

It was my understanding that feeding from the point end was always good practice, no matter dc or dcc.

 

I never like the idea of gapping the ends of any turnout unless it is absolutely unavoidable.  My preference is to add power feeds on every end of every turnout.  

So, in the present case, I would add feeders on the three pairs of frog rails on that 3-way turnout and then place the gaps a little further east of the tail end of the 3-way turnout.  That way, power feeds can also be added on the tail end of the 3-way turnout.  Why?  Because a turnout with an isolated frog raises the possibility of disruption in the electrical continuity of the turnout if any of the turnout's jumpers fail.

That said, the lack of power feeds and/or the presence of gaps should in no way cause a short on a turnout with an isolated frog.

Rich

Alton Junction

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