1. Presumably you have a power source connected to the track. Please describe what you are using.
My power supplies are not traditional model railroad transformers. They consist of three 6.3V 20A transformers connected in series. I have three of these units in service, and three more to come online in the future. Each gang of three has a grounded power cord, though the ground is not connected to anything. There are fuses on the hot primary, and the secondary is tied to a terminal strip for distribution. Each block is protected by a 6A polyswitch.
2. You mentioned that you have isolated rails. Do you have anything connected to them for accessories or signaling? This would be a likely spot for a connection to earth ground.
At this time there is nothing connected to the isolated rails. Eventually they will be used for detection, and tied to a computer with a system called CMRI, but that's way down the road. There are no signals or accessories on the layout.
3. What value of resistance did you get between the rail common and earth ground?
Zero.
With Gargraves track, you shouldn't have any problems with ties shorting to your foil, screen and ground wires. What do you use for switch machines, and do you have them wired for anti-derailing?
My switch machines are custom made screw drives. They have no electrical connection to the track, and no anti-derailing. They are connected to the switch with bell cranks and RC pushrods. None are operational.
The goal is to get this debugged before making it more complicated.
