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The circuit breaker on one of my 2 ZWs (new in 2004, used under 5 hours a month since) keeps tripping as soon as I power it up.  I’m trying to diagnose which of the 6 blocks on the layout is causing the short circuit.  Each block is powered by its own PowerHouse, same vintage.  All track is FasTrack, and each adjacent piece of track in each block is wired together with soldered connections.

The short first appeared recently, after cleaning the track with CRC contact cleaner, one of the non-polar cleaners recommended in Model Railroader Hobbyist of May 2019, Publisher’s Musings.  Before that there was never a problem.

All cars and locos are off the track and I’ve gone over every inch of track to make sure there is nothing to cause a obvious short.

As a first step to figure out which block is causing the short, I was thinking of turning off one PowerHouse at a time, and then powering up the ZW to see whether it still trips.   Question 1:  Will this damage anything?

Question 2:  If the ZW does not trip with that PowerHouse turned off, does it pinpoint the problem to that block of track?

I’m sorry to ask such a naive question.  I’ve not used my layout in 10 years and am amazed how much I’ve forgotten in that time, even after building the layout myself.  I’d sincerely appreciate any help or direction Forum members can provide.

Last edited by Allan Miller
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Start with the first position alone as one PowerHouse Power Supply must connect to the input jack to the left of the “A-U” thumbscrew terminal pair, regardless of other PowerHouses connected, to power the controller.

Once you rule out a short on this power district, turn on the others sequentially, leaving the first one powered for the remainder of the testing.

Thanks, Rob, I'll try it later today.  And I also appreciate your rapid reply.

Bob,

Clearly you don't have a ZW, but in fact it's a ZW-C.  These are very, very different things.

Could you possibly change the title of this thread to reflect that it's a ZW-C, to avoid confusion when someone searches for problems similar to yours in the future?  They deserve to see Rob's recommendations if these might help their situation.

Mike

Mike -

Great suggestion, I'll change the thread title as soon as I can figure out how to change the thread title.  I searched several of the sub-forums with all the words in "change forum title" but nothing relevant came up.  Can you point me to instructions?

Interestingly, the Lionel manual that came with the ZW controller always refers to it as the "ZW -- maybe Lionel started using the correct model name later when they added subsequent models?

Thanks again.

Bob

Great suggestion, I'll change the thread title as soon as I can figure out how to change the thread title.

To the right of the first post, click on the link Manage Topic.  You'll see the Edit Topic link come up, click on that.

The edit window will pop up and you can edit the title.

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Last edited by gunrunnerjohn

I wonder what track are you using? Also, years ago Lionel had different inserts for some if they’re ZW-C’s transformers, a longer plug that connects the bricks together. I for one have that ZW-C transformer. That may be of no concern, just a thought. My other thought is you could have a wire crossed possibly a common, outside rails, connected to a power, middle rail…. Last, are the transformers phased properly? That’s just for consideration. Good luck, and keep us informed.

Thanks for confirming, John.  And I'm presuming the first position needs to stay connected on only 1 of the 2 ZWs.

Thanks to you too, Larry, for the suggestions on connecting the bricks together, will look into it.

My plan of attack is to figure out which of the 6 insulated blocks is causing the problem, then examine all the wiring for that power district.  But I'm not counting on finding anything since it's been working fine ever since building the layout back in 2004.   The short appeared immediately after cleaning the track.  I've been wondering how track cleaning could have caused a short -- maybe pressing down too hard on the track while cleaning it?

Best regards to both of you and thanks again for your help.

Any guidance on how to determine if the circuit breaker tripping is due to the transformer rather than a track wiring problem?

Also, is there anything I need to do to ensure the two ZWs are in phase?

Thanks,

Truthfully, it's VERY unlikely that the transformers can cause the ZW-C breaker to trip.  Now, if it's one of the bricks, maybe it has a problem.

If the input transformers are in phase, the two ZW-C's are also in phase.

Thanks very much, John.

Today I tested each of the 6 blocks by 1) turning all of them off (except for the first one powering the ZW-C, which also powers block 1), and then 2) turning each one on, one at a time, and watching for the ZW circuit breaker to trip.  To my surprise, none tripped the breaker, so I turned all 6 bricks on at the same time to see if the breaker would trip.  It didn't -- so the original problem apparently vanished, and the only thing I did was to turn each brick on and off.  The multimeter shows 16.4v on the track in each block.  I'm stumped -- how on earth could turning bricks on and off fix the short?

A schematic for the ZW and brick wiring is attached, in case it has some bearing on the curious results.  It's worked fine since the layout was built in 2004-05.  I welcome any comments or suggestions you have.  I think there's likely a good deal of overkill, but at the time I set it up this way to make sure each block had plenty of power for multiple turnouts, crossing signals and locos.

Track Power Schematic

Meanwhile, however, another problem has cropped up.  In one block, any loco in it shuts down, which I've heard to indicate a loss of the TMCC signal.  The block is the most distant one of all from the ZW, about 35-40' in total.  The wire feeding it has 3 or 4 junctions at terminal strips along its length, i.e. it is not one continuous wire from ZW to the power drop of the block. Multimeter shows 16.4v just like the track in all other blocks.

Do you think the loss of loco control is due to a weakened TMCC signal?  If so, is there a signal boosting device that could be inserted into the wire feeding the block?  Or do I just need to bite the bullet and re-wire that block with a continuous piece of wire?

Thank you very much for all your help, John.

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  • Track Power Schematic

John -

Yes, the headlight flickers and immediately the loco dies.  Holding my hand 3-4 inches above the loco does nothing to start it up again or to keep it from dying.  However, when I touch the loco, the lights come back on and the engine starts up, but only for a second or two, then everything goes out again.  I can touch it repeatedly with the same result -- the loco won't stay on.

John -

I placed a 15 ft household (lamp cord) extension cable next to the track, anywhere from 3-6" away from the track depending on scenery obstructions.  I extended it several feet on both sides of the area where the engine shuts down.  It made no difference -- the engine still dies.  The engine lights stayed on, but the loco didn't respond to any of the TMCC controls, including the throttle.  I confirmed this with a second identical loco.  The track voltage was a constant 15.6v throughout the block.

I tried to narrow down where exactly the signal is being lost, by running the train into the problem area from the opposite direction.  The problem section of track is about 30-40" long, and it's made up of several straight track sections (FasTrack) with a turnout in between.

Attached is a schematic of the layout to show where the problem section of track is located.  Also attached is a pic of the problem section of track under the SD70 and first coach, obviously taken before the problem emerged.  In case you need to see more pics, they're posted on my Flickr site, https://www.flickr.com/photos/22349380@N05/

I'd greatly appreciate any further suggestions.

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  • Layout Track Schematic
  • View of Problem Track Section (under the SD70 and first coach): 2014-08-07_042

You cannot use a 2 wire "lamp" extension cord. You need an earth grounded wire (3 prong plug and matching 3 wire cord). Using a 2 wire cord (2 prong plug) may defeat the purpose of testing.

Again, the entire purpose of this test is adding an earth grounded wire- at the same potential as your earth grounded power adapter powering your (Edit- TMCC) base, near the area of track where you are losing TMCC signal.

Last edited by Vernon Barry

You cannot use a 2 wire "lamp" extension cord. You need an earth grounded wire (3 prong plug and matching 3 wire cord). Using a 2 wire cord (2 prong plug) may defeat the purpose of testing.

Again, the entire purpose of this test is adding an earth grounded wire- at the same potential as your earth grounded power adapter powering your (Edit- TMCC) base, near the area of track where you are losing TMCC signal.

The 3-wire extension cord needs to be plugged directly into a properly wired 3-prong outlet.  Don't plug it into a surge suppressor.

John, Vernon and Vince --

First, I sincerely thank each of you for your interest and guidance in trying to figure out the problem I'm having.

With the correct 3-wire grounded extension cord in place alongside the track in the problem area, and plugged directly into a wall outlet (and not a surge suppressor), I powered everything up to run an engine through it.  The extension cord was placed within an inch of the track, and it ran approximately 10 feet so that it covered all track in the entire problem area.

I started an engine on the other side of the layout and moved it to the problem area.  It responded normally to all cab controls.  When it entered the problem area, the engine died.

However, this time I noticed that as the engine entered the problem area, its lights first flickered a couple of times, but they stayed on (as did the sound) as the engine came to a stop.  Immediately after stopping, the engine jerked forward an inch or two, and then stopped again.  Then this cycle repeated 2-3 times.  Meanwhile lights were still on.  It was if I were very quickly alternating cutting the engine's power and then throttling it up.  After the second or third time, the engine went dead.  I couldn't bring it back to life using the cab throttle.

I repeated the test, this time holding my hand directly above the engine as it entered the problem area.  Same result as before.

I did find I could bring the engine back to life momentarily by rocking it gently from side to side on the tracks.  However, it would die again immediately.

As I said in an earlier post, I get the same results with an identical engine running through the problem section of track.  In fact, looking back, multiple different locos died as soon as they entered the problem area.

In all cases, I tested the track voltage in the problem area, and it was a constant 15.6 volts, the same as track throughout the layout.

Any thoughts or suggestions on what else I could do that would help pin down the cause of the engine dying in the problem section of track?

" I tested the track voltage in the problem area, and it was a constant 15.6 volts, the same as track throughout the layout."

I have to question that testing.

Was it done, under load, the exact condition at the spot with the train weight on the joints exposing intermittent and higher resistance track joints? In other words, the meter connected to that track section, and then the train run around on top and watching that point and the voltage varying as the train passes?

Edit, even better testing would be a meter in the train engine, right from the pickups, displayed outside and continuously as the train passes around the track and specifically the problem section. Obviously not practical in some cases, but a good test engine and one of the best ways to see actual under load conditions what the engine is actually getting.

I'm worried of a lack of understanding of how resistance and intermittent track joints plays into this, and the fact the meter being high impedance and just going around a track spot measuring voltage using a typical meter, is potentially invalid and possibly misleading testing one can do without additional context and an actual load at that point.

Last edited by Vernon Barry

I’m responding to this based on reading your heading of the ZWC tripping on start up. Reprogram the ZWC so that handle A controls voltage of all 4 channels. Always power up with handle A in the zero voltage position. Instead of a full blast of 18 volt going to the tracks simply increase the A handle gradually. It eliminates the high inrush. It worked for me.

Sorry for the delay in responding - family have been visiting and I couldn't really get away until now.

Thanks to all who contributed their thoughts - John, Side Rod, Vernon, Ken and Rod.  This is a real puzzle and I can use as many ideas as I can get in trying to solve it.  Funny that when the layout was new 18 years ago there were no such problems -- so the flexing track hypothesis is certainly plausible to me.

Two additional pieces of information that may be relevant:

1)  The problem area is right above the joint between two tables.  While the tables are bolted together very securely, there may have been some very small difference in their height.  I tried pressing down on the track today to see if there any give, but couldn't feel or see any, but it was an arm's reach away and I can't say for sure one way or the other.

2)  The problem area track has a past history that may be related to John's hypothesis.  It emerged after 7-8 years of operation.  Specifically, engines lost their sound (not their lights) as they entered the problem area, but continued to run through it.  The sound came back as the engine gained distance on the problem area, or when I hit the whistle/bell button.  Before now, engines have not died in the problem area.

So could the problem could not only be power interruption -- but also TMCC signal?  Vernon, I'll try your recommendations on better testing.  However, I have to confess to being an electrical novice, so you may be throwing pearls to swine with me -- but I'm certainly game to learn.

Rod, the ZW circuit breaker has problem has gone away - although I don't see how just turning on and off each brick -- which I did to try to isolate the block causing the problem --  could have fixed it.  Once it resolved and I started running trains again, engines started dying in the problem track area.

Finally, Side Rod and Ken, I agree with your suggestion that maybe the simplest solution (or test) is to replace the track and turnout.  I groan at the thought, though, since it would mean tearing up a good deal of ballasted track and landscaping as you can see from the pic.  But I'm sure I'm not the first to have to do this.

Thanks to all again.

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