[OceanIsSoPlane]

So I've been an avid model train enthusiast for about 10 years now, and I decided to bust out and put together everything I owned yesterday. However, there is a section on the second track (the one with the CSX diesel on it) that appears to not have power supply. The only places where it won't run is between the CSX loco and the V7 double cross interchange (not sure what its called, but the switch from the second track to the third track (the track with the bridge)). The power is supplied through the blue cable hooked up to the tandem rail. Any ideas why this area doesn't run?

 

[DonR]

Use your multimeter to determine exactly where
you are losing power. Some times the joiners are
not making proper contact.

If you have special power jacks in the track system,
sometimes these have been known to need attention
to correct a bad connection. On some track systems
it's possible in accidentally reverse the polarity at the
jacks.

Let us know what you find.

Don

 

[CTValleyRR]

Your train won't run for one of two reasons: either no power is getting to the loco, or you have a polarity conflict. I would guess it isn't the latter, because that would take out a much larger section of track (although I admit that in your photos I can't tell for sure which loco is the CSX one).

So you probably don't have power to the loco. That's the easy part. The hard part is figuring out why.
Some questions to answer:
1) Are you sure the loco runs (not when you put it away, but now).
2) You have 3 power packs. Do you have track sections insulated somehow so that each powerpack powers a section of track? Have you accidentally installed an isolated section in that spot?
3) Are the power contacts in the Unitrack clean? Especially from carpet fuzz?
4) Is the sponginess of the carpet causing a slight misalignment in your track joints, preventing good electrical contact?

BTW, if you don't have a multimeter, you can substitute a 12V auto or flashlight bulb with test leads attached to it. Set your power pack(s) for about 70% and that should be a little less than 12V DC.

You probably noticed something of a theme above: model trains and shag carpets don't go together very well. I'd strongly recommend getting those trains up off the floor before something gets permanently wrecked, either by being stepped on or by picking up dirt or fuzz from the floor.

 

[OceanIsSoPlane]

So based off of my findings from the two suggestions given, I got a positive reading on all parts of the track except between the middle of the double crossover and the CSX loco (the one on the second track) where I got a reading of 0 with a multimeter. Upon removal of the double cross, the entire loop ran smoothly, as tested with the CSX loco and other engines I had on hand. I suspect the issue is with the double cross (V7). Any ideas as to what's faulty about it? I've used the double crossover in the past, and have never had an issue with it. I'm currently in the works of building a new table for this set, but got to desperate to lay it out since I am on winter break.

 

[CTValleyRR]

Look underneath the double crossover. Something may be shorting across the rails underneath. It could also be something in the carpet. Some of these have a jumper to provide power to the adjacent rails; this may have become bent or gotten moved, and is touching something it shouldn't.