# What causes switch to start causing shorts?



## tkruger (Jan 18, 2009)

OK yesterday had an issue with may layout. The 4 track yard uses all Peco #4 switches, 1 as an entrance from the main, switch #2 to enter track 1, switch #3 to enter track 2 and finally switch #4 to split between tracks 3 and 4. 

While using the yard all of a sudden everything starts shorting out and resetting. Nothing was derailed. It was occurring when I changed the points on the #4 switch. Emptied the tracks of all cars etc. and as soon as the points changed to point into track #3 the short occurred. Using track #4 no issue. So I disconnected both tracks 3 and 4 from the switch, same issue. Swap the switch for a spare I have and the short is gone. Everything looks visibly OK on the old switch. The multi-meter does show that the diverging tracks are shorting when the points are changed (and they stay shorted until they are turned back to allow a train to run straight through). It has worked fine for some time. Any ideas why this happened? Has anyone else had a Peco switch fail like this? This was a DC layout for ~3 years without issue and changed to DCC at the beginning of fall this year.

BTW to ad insult to injury while pulling out the switch I broke a wire to the outside rail on track #3. I have an wire with an alligator clip as a temporary fix for this now. hwell:


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## DonR (Oct 18, 2012)

Your problem sounds like you have PECO ELECTROFROG turnouts.

If so, you must put an insulated joiner in the frog rails where they
meet the other tracks. When the frog is changed from straight to
diver it's polarity changes and that causes a short in the divert track.
If you want to maintain power in the connected tracks you might
want to add a drop from from the frog rails.

It is odd that they worked for DC but shorted DCC. The frog
rails come together with only a tiny sliver of plastic to
separate them. Could a change in temperature have affected that
point?

I use Peco INSULFROGs and never have experienced this problem.
They are power routing but the frog is plastic so no insulated
joiner is necessary.

Don


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## tkruger (Jan 18, 2009)

DonR said:


> Your problem sounds like you have PECO ELECTROFROG turnouts.
> 
> If so, you must put an insulated joiner in the frog rails where they
> meet the other tracks. When the frog is changed from straight to
> ...


I have been running these as DCC since November without issue. The room is in the basement and only heated when in use. Maybe something just wore out while we were using it.


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## DonR (Oct 18, 2012)

Didn't you have a similar problem a few weeks ago here on
the Forum and found that
when you converted to DCC that you had inadvertently flipped
a buss feed. Could that be involved with these events.

Gotta be something of that nature, because you know the
quality of your Peco turnouts. They're not going to suddenly
fail enmasse.

I am assuming that your multimeter test showing a short when
points set to divert was while the turnout was installed in the layout.

If the diverting track were inverse phase to the straight track you
would get a short when points diverted no matter whether 
Electrofrog or Insulfrog. Insulfrog is power routing so when
diverted the power would hit the inverse track and short,
but no short when set straight.
If Electrofrog the same would occur.

You can test the divert track phase. Set meter to AC;
put one probe on the straight solid rail, while points set
to straight. Put the other probe on the frog rail of the
divert track. If you get a voltage reading the divert track
is out of phase. Flip that and you're back in business.

Don


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## gregc (Apr 25, 2015)

tkruger said:


> I have been running these as DCC since November without issue. The room is in the basement and only heated when in use. Maybe something just wore out while we were using it.


while I hand-laid my turnouts, I had a very similar problem just yesterday. Everything was working well a week ago.

Eventually I found that a short occurred with one turnout. One of the gaps closed on one of the frog rails, just as DonR described. I ultimately cut-off about a 1/16 in. of rail.

It got real cold (0 deg) here in new Jersey. I assume the dew point (humidity) got real low and the benchwork contracted. Wonder what's going to happen tomorrow when we have rain and it's nearly 50 deg.


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## tkruger (Jan 18, 2009)

DonR said:


> Didn't you have a similar problem a few weeks ago here on
> the Forum and found that
> when you converted to DCC that you had inadvertently flipped
> a buss feed. Could that be involved with these events.
> ...


This was a different location than the prior incident. The switch was working fine earlier in the day. The multi-meter shows that the diverging track is shorting when it is not connected to the layout, i.e. completely removed, thus why I am confused. Both rails on the diverging side show connectivity to one-another. Thus power must be able to flow between them. Prior to the frog this is not the case. This is the only switch I have had fail ever in this manor of any kind.

To fix the issue (after much testing) all I did was swap out a spare I had and placed it back in place. Everything now worked again. Another reason to believe something is up with that switch. I just wich I kew the cause since this is so out of the ordinary.


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## DonR (Oct 18, 2012)

I agree. It sounds like something in the turnout's internals has
gone wrong. You should be able to see some of the connections
on the bottom of the turnout. Maybe you can trace the problem
that way.

Look where the two frog rails come together top and underneath
that where the two sides of the circuit are very close together.
Is there, maybe, a sliver of metal that has wedged into the
plastic insulation between the frog rails?

Don


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## tkruger (Jan 18, 2009)

Something is loose but not sure what. Retested when the room was cold and no short. Have heat on a while and guess what, there is a short. 

I am just going to let the switch be and not use it again. It has been replaced on the layout with a working one. Might use it in the scenery line if one is needed there, I have a spur that goes into the background behind a building with a few cars stored on it.

Thanks for everything.


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## DonR (Oct 18, 2012)

Dog gone...hate to give up on a problem. Since temperature
affects the short, you have an expansion and contraction
issue, and I still say it's gotta be related to those frog rails.

Don


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## tkruger (Jan 18, 2009)

DonR said:


> Dog gone...hate to give up on a problem. Since temperature
> affects the short, you have an expansion and contraction
> issue, and I still say it's gotta be related to those frog rails.
> 
> Don


I agree but since the layout is up and running I have other things I have to fix a switch that will not be put back on the layout or one of a million other task, or just watch the trains roll by. I am thinking the last one is the most satisfying at this point.


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