Setting up the trains for the grandkids for Christmas and hit a problem I have not experienced before. Before I screwed the tracks down I ran a motorized car on the main line. It’s about 35 tracks long. It went around a few times then died, with the red light on the transformer going on. I did find one track where the insulation on the center rail had slipped off. I repaired it but it is still shorting out. Any other ideas to check out would be greatly appreciated. Thank you.