I too am having issues with EZ track #4 switches. I have at least four that were dead right out of the packaging. Customer service referred me to the forum. I tried making sure the frog was powered but so far they remain a dead short.
I am at a loss. Any help would be appreciated.

you are correct in the layout of the track, the main loop is independant. Throwing the switch causes the power outage.

I decided to take the switch out and replace it with a switch from elsewhere on the layout. This solved the problem with the yard, and when I put the switch in elsewhere on the layout the problem began again. I am sure it is a bad switch,  however I dio not know why or how it is bad.

Thank you all for your advice!

I am getting back into modele railroading after many years. I went back in using Bachmann EZ track and have had great success with it so far, it made track laying much less frustrating. As I have expanded my small layout I decided to begin to add a small classification yard. I installed three EZ track left hand #4 for the ladder. I insulated each line at the end of the switch to provide independant operation and use an atlas switch box to power each one as needed. The center #4 switch of the three when opened to allow the train to proceed straight into the line works fine, when I close the switch to move the train to the next line the power is killed to the whole line. I suspect I have insulated at the wrong spot but I am lost. Any help would be greatly apprciated!