Unable to find the short

[Jay]

We have not run trains in some time and felt it would only inspire us
to move quicker on the layout if we started to run them again. So on
the freight yard leg (a section that worked previously) I connected
power to it and my Digitrax DCS100 shorted and shut down the system. I
have disconnected the rest of the layout from this area, checked for
something on the tracks and verified wiring under the layout. I can
only come up with that after ballasting and painting that a switch is
shorting. We are using Atlas snap switches and a Digitrax Super
Chief. Any ideas would be most helpful .. thanks!

[RAM]

make sure that your gaps are still gaps. 

[Jay]

Thanks RAM,

I have double then triple checked this and all gaps are still as they should be.

[r.cprmier]

If you can't find it, go backwards with respect to which way you worked.  A good idea in the future, is to check each section of track for shorts with a good multimeter.  make sure that you throw all turnouts back and forth in the process.   

Now, with what you have, you could isolate it section by section and check what is happening.  I would do it with some sort of indicator light, and when the light goes out, you will have found your problem.

I would not hook any DCC unit up to that track until you have double checked your work.  You could get past protection and create your own personal light show!

Rich

[Jay]

And so the learning continues.  I am going to break the section down to three power districts instead of the one big one that I am working with not.  Once I do this I will be able to see which of the three are causing the problem and will help very much to find the trouble spot or spots.  Thanks for the insight.

[VirginiaCentral]

You know, sometimes the short can be in the locomotive or other rolling stock.  If you are still having problems, check your cars and engines for direct shorts.  Yes, I know engines and some cars are supposed to "short" the power, but it is a short through a resistance, not a direct short.  You should check your equipmenbt for direct shorts that bypass the motors and/or lights in the cars.

Jerry

[Jay]

Thanks Jerry,

I have tried testing it with no rolling stock or engines on the layout, which leads me to believe I have a track issue.

[r.cprmier]

Jay;
Try to find a meter with a D'Arsonvalt movement (needle), and put some alligator clips on the leads.  isolate a section of track, clip on the leads, and set the resistance to "RX1".  Oh, make sure the power to the track is shut off completely. 
If there is no short in that section, the needle will not deflect to the right; if there is a short, it will.  As per Jerry, you can also see if there is a resistive short, because the needle will only partially deflect, and will probably sit on a low number.  This can also happen if you have a DC locomotive on the track, as the motor generally reads about 8-11 ohms.

As you isolate the track sector by sector, you will eventually find the culprit.  It could be something as innocuous as a finishing nail across the rails, so keep your eyes open ,and don't expect the exotic more than the mundane; My experience is that the causes are usually simple.

Rich

[JerryB]

Jay:

Maybe too obvious, but have you tried disconnecting the wires at the power supply, then turning the power up? If that is OK, then try it with the wires disconnected at the track.

This will prove that the power pack is good and also test the wiring. Sometimes the wires can be 'frayed' and shorting at the connections.

Happy RRing,

Jerry Bowers

[Jay]

I did find the short last night.  The issue was with an Atlas Snap Switch in which the the rails on the frog ended up touching.  Maybe because of soldering joints?  I am not sure.  We have replaced the switch and all is well except for now putting every thing all back together.  Thanks to everyone for their ideas and help to resolve this problem.