Dear Scott,

Any chance of a track diagram/schematic, with indicated positions of feeder locations? Without such basic info, I doubtanyone would even hazard a guess.

7x13 is actually quite a decent sized layout when it comes to wiring, I personally rarely exceed 2x4 without introducing some form of "sanity check" isolation system. (Ask me about the 2x4 On30 curve module, with _one-only_ turnout, which prompted over 4-hours of head-scratching... the "fault" ended up being 1 single gap which I had forgotten to cut... my excuse is that the phone rang just as I was about to cut it, and thus forgot... :-) )

In direct answer to your question, yes, there are tools which will detect "short circuits" in simple circuits. These can be had for around $100, and are sold as Audio cable testers. They use basic resistor/capacitor network theory to detect within a foot or so where the issue is. However, they are designed for use with simple copper end-to-end cables. As such, a _complex_ wiring situation such as an entire layout may present multiple points-of-failure, or simply too-ambiguous a test result.

There are also much more expensive units available, desugned for use in the electronics mamufacturing industry. These units inject a pulse-coded signal into the GND plane of multi-layer pcb circuit boards, which can then be detected and localised using a probe also connected to the test unit. Using these in the context of a fully wired layout will require the operator to have a pretty solid understanding of the test unit, how it works, and the layout wiring they are testing.... (no point connecting both the injection signal and the probe to the layout "GND", and wondering why the unit registers shorts _everywhere_... :-) )

In short, I fear that this one will be brought home by basic diagnostic work. If that requires de-soldering some existing jumpers or feeders, then so be it...
(Would you rather tackle un-and-resoldering some feeders on the way to a working layout,
Or leave the feeders as-is and not-resolve the problem?)

Happy Modelling,
Aim to Improve,
Prof Klyzlr

PS there's a morale to this story, even "small" layouts need provision for diagnostics, because no matter how "small" or "simple" a layout is, Murphy's Law has not yet been repealed... :-)

Scott - you may want to check out this thread:

http://model-railroad-hobbyist.com/node/8596

I agree with Professor Klyzir about a schematic being necessary.

One other quick thought:  You may have soldered red to red and black to black, but did you solder all the reds to the same rail of the track and all the blacks to the same rail, electrically speaking?  If you're lucky, you might quickly find a misplaced feeder.

Dante 

I will work on a drawing tomorrow and I will double check on the orientation of the feeder wires.  Unfortunately, I insulated all the feeder to buss connections after I confirmed continuity of each connection to its appropriate rail.         I am dreading having to get under the layout to start cutting loose feeders.  Doing it the first time was quite painful.  It promises to be doubly so the second time.  Not looking for sympathy, just verbalizing the dread.

Scott Groff

  Is it flex or sectional or hand built?  I'd start first by double checking all the top to make sure there is not a scrap piece of metal or a tool somewhere between the rails. Next I'd eyeball all the rail to bus connectors again to double check that they are not crossed somewhere. Then unhook the DCC and check the track with an ohm meter to make sure the short is actually in the track work.  If everything checks out then I'd cut the layout into 2 blocks by dremeling gaps across the rails and cutting the bus. Once I knew which half was the problem I'd cut it into 2 parts to narrow it down further. Once it gets confined to a small area then it should be easy to find the ultimate culprit. Put it back together by splicing the bus back together with wire nuts or terminal blocks and it will be easier to trouble shoot next time :>) ....DaveBranum

When I do ANY wiring on my layout or any other project for that matter, I "test as I go".  This way you have a much more likely chance of catching a mistake or issue BEFORE it becomes the 800lb gorilla in the room!  I would suggest starting with one set of feeders at a time and start with the last ones you soldered and work your way back to the first until you find the short.  Not going to be easy but just take your time.  Do one wire at a time and TEST!! Then test it again and just to be sure test it a third time before moving on.  I learned this through experience as a full time marine technician.  In my line of work you usually only get one shot to get it right! Otherwise you get to fix it for free!

Dear Nelson,

Sounds like an sawby I heard from an old Audio Technician,

"...there's never enough time to do it right the first time,

there's always time to do it right the second..."
(NB he said this as he started into tearing apart an entire 6' rack of freshly-wired patchbays and Dsub 25 connectors,
having realised that the previous tech had followed Dsub 25 "Digi Spec" pin-outs,
and the devices in question used Dsub 25 "Yamaha-Spec" pin-outs... :-( )

Happy Modelling,
Aim to Improve,
Prof Klyzlr

Suggest you build one of these testers documented on http://www.wiringfordcc.com/track.htm

Scroll down to the testing section.

This has saved me a lot of time, it's cheap and you can build this in 5-minutes.

Like you, I had all my feeders and track busses color coded.  It was red to red, white to white.  What could go wrong?  Well, I wound up with a short.  Of course, wouldn't you know that I had still managed to connect a red feeder to the white track buss.  I have no idea how I managed to do that, but I did.  

Since then, I test for shorts after every couple of feeders.  The other day, I attached two feeders and wound up with a short.  Disconnected the two feeders and still had the short!  Now I was perplexed.  Careful inspection revealed that I had left a small spool of soldering wire sitting perfectly across two rails.  Lesson learned.  Keep stuff off the tracks.

Please let us know what you find.  We can add it to the considerably lengthy list of troubleshooting ideas for shorts.

John C

Since I am in the track laying and wiring phase on my layout a couple of techniques I use to keep from causing shorts. I am using the Tim Warris switch building pattern and every time I file a gap on any PC tie, I get out my trusty, cheap digital multimeter to make sure the gaps are complete.  So I am strong follower of the test, test, test philosophy exhorted in all the previous responses.  Yes, everything is color coded, in my case the inner rails are all red, the outers are black.  Frog connections are all green.  To help during the wiring hook up efforts I set my trusty, cheap digital multimeter to The Continuity Check with the red test lead to the VOMA terminal and the Black test lead to the COM terminal.  The Range switch is set to the hFE )))) position.  The buzzer sounds when you hook up a short connection and is really handy while under the layout to know you did a no-no.

I find the audio alert is really hand when working in the underworld and it save a lot of future embarrassment and agony.  To ensure good connectivity for the test leads, I picked up an extra set of test leads which I fitted with alligator clamps to allow solid connections with the rails in the area I am connecting.