Please bare with me as I try to explain my situation. I have a DSC layout using Fastrack track and switches. I have 3 transformers: one each for track, switches and accessories. All seemed ok until I decided to try to isolate a “yard” via a toggle switch. I am using a short piece of track for isolation by cutting the rail. I first tried to isolate by cutting the outer rail and leaving the center rail uncut. This piece of track is just before a switch to the yard. The outer power was wired thru the toggle switch with center rail power left uncut if you will. I found that in this case the engines were always powered “on”regardless of the position of the toggle switch. Intially I thought I had a bad switch Further investigation has revealed the following . I turned all three transformers off. I disconnected the switch from all the other three pieces of track typically connected to it, also disconnected the three control wires from the IAU, but left the two power leads connected to the switch. I accidentally discovered that if I jumpered the center rail of the switch to the center rail of the “main line” track and then powered on the “track” transformer, that the switch rails were all “hot” without any jumper on the outside rail. I connected a couple pieces of track and put a engine on it and the engine would power up under these circumstances. Maybe to clarify, I had no power to the switch except thru the jumper on the center rail. All this with the switch power transformer off and even disconnected from the terminal board I use for distributing power to the switches. I then disconnected the two power leads to the switch. This did kill both the center and outside rail power. I then found that removing the red wire of the switch power had no effect, but it was the black lead to the ground terminal on the switch that created the “hot” rails. In summary with track on and power to only the center rail of the switch and the non-powered switch power ground wire attached, I get “hot” rails, but if I just remove the ground wire from the switch, the rails go dead. So how is the outer rail getting power from the black ground wire connected to the switch power terminal. Faulty switch? I did the same test with two spare switches with the same results! Any thoughts as to why this is happening.
Thanks in advance for your input.
