DC short circuit


SilverBlade

Member
I am stumped by this short circuit. It makes no sense to me at all. If you guys can help me out here I'll give you a big sloppy kiss. Here is my layout so far:

ShortCircuit.jpg


I'm using Peco Insulfrog turnouts.

OK here's my problem: I wired up P-1, P-2, and P-4 without any trouble. I can move trains between the main line and the yard normally. But as soon as I hook up P-3 I get a short on the main line. I can still run through the yard, but if I switch either turnout S-1 or S-2 to the main line my loco slows to a crawl. Switch both S-1 & S-2 and it dies completely. But here is what really stumps me: Disconnect P-3 and the problem still exists! I've gone through this several times. P-1, 2, & 4 don't cause a problem but once P-3 is wired in the main line shorts and the short doesn't go away when P-3 is disconnected. Then a few days later the short circuit fairy comes and waves a magic wand and the main line just starts working again.

WTF!!!

None of the electrical leads above P-4 are connected right now and none of the turnouts are powered yet. Because of computer issues I can't post a pic of the wiring but I've traced all the wires a dozen times and absolutely nothing is crossed. It's all above table right now anyway so it's fairly easy for me to be sure. P-1 is close to the power supply but P-2, 3, & 4 have to be spliced together into 1 wire before I run them to the power supply. But again I am certain the polarities are separate so why should that be a problem?

Peco turnouts are power routing (which I've decided I really don't like) but surely they don't reverse polarity, right?!

I've been studying this for 2 weeks and it just doesn't make a bit of sense to me. Please help!
 
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I'm wondering if this insulator is on the wrong side as it seems to be insulating a positive and negative track, check and make sure it's on the right track
 
Are you using electrofrog turnouts? What brand are you using?
I had a similar problem with my PECO turnouts last year. I had bought insulfrog units but one of the boxes had the wrong turnout in it (electrofrog) causing my Short.
Can you run on P3 without hooking it up?
 
Just fixed my computer issue so I can upload pics.
UPBigBoy - That's just the limitations of Right Track software. Here is the actual insulator you are pointing to:

ShortCircuit3.jpg


hamltnblue - There is one Atlas turnout (upper right corner and doesn't appear related to the short) and the rest are Peco. Just put my finger on every single frog. All Insulfrogs.

Yes, I suppose I could live without P-3 all together. But I want a lot of power feeds because with the power routing turnouts it's not hard to turn off a block of track while a train is still on it by switching turnouts well in advance (and who doesn't do that?). Also it just irritates the BeJesus out of me that this makes absolutely NO SENSE! There is nothing here that should be causing a short. Now I just want to know what in the crap is happening.

This is the terminal block where the wires are tied in to go to the power supply:

ShortCircuit4.jpg


The electrical leads from P-3:

ShortCircuit2.jpg


The splice where P-2 & P-4 are joined and wired to the terminal block:

ShortCircuit5.jpg


If any other pictures might help I be happy to post them.
 
I'm wondering if these turnouts are acting like Shinohara turnouts - The frog polarity is changed by which point rail is touching which stock rail. The polarity of the frog also makes BOTH the short rails extending from the frog the same polarity. The only way to correct this is to put an insulating rail joiner on BOTH of the rails coming from the frog.

Not sure how the power routing works on your Peco turnouts, but your symptoms sound exactly the same.


Mark.
 
To the left of P3, is that a crossing and not a double slip? Interesting problem but I sure don't see a reason.
 
Both main types of Peco turnouts, electrofrog and insulfrog, are power routing. That means you must gap the rails meeting each of the two routes beyond the frog. Both rails. You have a choice of gapping it right where the turnout's diverging routes end or using metal joiners there and gapping it at the next turnout on the other end of the length of rail....but gapped they must be. Means lots of soldered feeder wires, but that is how I got my yard to work so well.

Your short is an indication that you have points thrown that 'contradict' each other somewhere on your track system. I would suspect the next turnout in line beyond your sequence of power hookup to this point. If throwing those points doesn't cure the problem, then it's the one next, and so on and so on....

Try gaps.
 
I'm wondering if these turnouts are acting like Shinohara turnouts - The frog polarity is changed by which point rail is touching which stock rail. The polarity of the frog also makes BOTH the short rails extending from the frog the same polarity. The only way to correct this is to put an insulating rail joiner on BOTH of the rails coming from the frog.

Not sure how the power routing works on your Peco turnouts, but your symptoms sound exactly the same.


Mark.

I believe that Mark has the answer. The rule for DC wiring in power routing turnouts, which you say you have, is that: All rails should be gapped to completely avoid an occurrence of a short. Although, as Mark says, you can get by with gaps in the frog rails only. You also feed rail power to the turnouts from the point end only! Common rail wiring doesn't work well with power routing turnouts. Without individual gaps in either all rails, or just the frog rails, with power routing turnouts, then a short will occur!

I use DCC, but all my turnouts are power routing. But because of my use of the DC wiring rule for power routing turnouts, (I go ahead put gaps in all 4 rails, and feed rail power to the turnouts only from the point end), the only time I get a short is when a loco/car derails or an engineer forgets to check turnout position & runs against it. These can occur anywhere/time, (although the engineer's mistake occurs most of the time, a derailment is an extremely rare event on my layout).

PS-Selector says it as well.
 
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If that is a double-slip, whose make is it? If it is one of the old Atlas, that is one thing; a Shinohara or other brand may be something else. In any even, you definitely need another insulated rail joiner in the downstream leg of the diverging frog rail of the Atlas turnout (S2). Without seeing the exact electrical type of the double-slip or crossing, I can't tell where the short may be, but if you don't need P3, I'd leave it out. You may need to feed power to the inner track from somewhere else, but these things can get tricky. I had similar problem in one area of a spagetti bowl, and it about drove me nuts until I figured out that an old Atlas Double-slip was shorting internally. I replaced it with a crossing, since I was able to reroute the track in a different location. Hope this helps.
 
It's an Atlas crossing not a double slip. So double insulators all the way around then. That's tiresome. I went to Peco because I was getting derailments with Atlas. But, I really don't see the value of a power routing turnout.

Anyway, thanks for the feedback.
 
You don't need any insulated joiners on the Atlas crossing. All you need is insulated joiners on the two rails beyond the frog of your power-routed turnouts.

Powered turnouts such as these can help save on some wiring if they head into a stub-ended track like a siding. By throwing the turnout against the siding, the power is essentially turned off - so you don't need a separate block switch to turn the power off.


Mark.
 
Any two Power Routing Turnouts (PRT's) that have the frogs facing each other must have gaps in the rail that connect the frogs. Feed power to the continuous rails of one or the other of the turnouts (the non-frog rails). When the points are thrown for straight route, the diverging route will have both rails the same polarity and will be dead. If the turnouts are thrown with one straight and the other diverging, the diverging route will be live up to the gaps, and the turnout thrown against the flow of traffic will stop the locomotive. (You may have a short if a long wheelbase locomotive bridges the gap, but usually you'll want to throw the other turnout toward the locomotive anyway.

Specifically, you need a gap between S1 and S2 frog rails. Rewire P6 to the outside rails (P2 may feed that siding anyway). Get rid of P3. P1 is feeding S2. You don't really need to feed both rails of the P6 through P9. If those stub sidings are gapped on one rail, you only need on-off switches, and if the main turnout that leads to that siding is a PRT, when the turnout is thrown to the other route, all power will be cut to that whole siding. The only reason I can see for all the gaps in that siding is if that is an engine storage track and you want to start on engine at a time, leaving the others on that siding stopped.

BTW, if that is a 4' x 8' layout, the only reason for feeding all over the place is if you have poor connections between the sections of track. That can be solved by either using jumper wires soldered to both sides of a connector, or by simply soldering the connector to both sections of track that it is joining. Sometimes, as a temporary fix to a loose rail joiner, I'll take a sidecutting pliars and squeeze the joiner between the two sharp jaws into the rail. I don't solder every joint, especially if I anticipate changing the track routing or need to remove a section for some reason (scenery under a bridge for example, which I may not get around to until after the track has been laid).

Hope this helps.
 
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