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I was running trains today and on my separate inside loop the train came to an abrupt halt and the red light on the transformer came on.  I took everything off of the track on the inside loop. I checked continuity with a multimeter and I got continuity between the outside rail and the middle rail. Do any of you have any suggestions on finding a short?  The train did stop in one of the switches. Any help is greatly appreciated.

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You have to break the loop down into sections and start isolating track sections to find it. Start with large sections and break down the faulty section into smaller sections or take out one section of track at a time until the faulty section is found. If you are using track with plastic or wood ties, it should be easy to find, probably a switch.

You can probably hunt it down by putting a much lower voltage on the track to generate a couple of amps of current.  Now you go around with a decent AC voltmeter and look for the place across the track that has the lowest voltage, that's near the short.

FWIW, I do this with DC as it's a bit easier to zero in with less variability than with an AC source.  I have a current limited DC power supply, I just set it to a couple of amps constant current and feed the track power and then I go hunting.  I've tracked down shorts on a loop a couple hundred feet long that way pretty quickly.

If everything was running fine and the short just came out of the blue, I'd start by a close physical inspection with a bright light, maybe a screw dropped off something and is the cause of the short.

I’m thinking the same as you John. I’m thinking something fell off of the train and caused the short. Ha! Might have known the suspected area is on the far side of the layout, very hard to get to. Heck, it’s been running great with no problems.

You violated one of the safety rules of layout construction, don't make hard to access areas!   You know that's where all the problems will occur!

Last edited by gunrunnerjohn

A few years ago I re-wired my whole layout because of a short. It turned out that the cause of the short was a wire that slipped out of a clip on a lock-on. LOL.

The re-wiring, however, was worthwhile because excess wire was removed, the wiring was simplified and organized better, and the trains run much better.  It was a good project to do during Covid. Arnold

Last edited by Arnold D. Cribari

Ok everyone, after an exhausting five hours of work this morning I think I have found the culprit. I checked the entire loop, red light still comes on. I disconnected every wire feeding the loop…red light still comes on. So I have a red and black wire from the transformer going into TIU fixed voltage line 2. I disconnected those two wires… no red light. I reconnected the two wires back to the TIU fixed voltage line 2 and I have no wire to the track. The red light on the transformer comes on. So, I’m guessing it’s the TIU?????

Yep, I know that power to operate the TIU comes through fixed input 1 and the fixed output 1 goes to my outside loop. Apparently fixed input 2 is shorted out. So can I just run my inside loop on variable input 2 set the transformer to 18 volts and run as usual?  

If you go into TIU settings for that variable channel and set it to fixed.

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