From Dale's treatment of the subject.
Avoid overwhelming the airborne signal with too much conducted Track signal
- Do not connect tubular track ties directly to metal bridges with metal mounting screws. Alternatives are nylon screws or using insulating shims and plastic shoulder washers.
- Beware of trackside accessories with metal parts that are tied to the layout’s common bus. This will put the conducted Track signal onto the metalwork. One solution is to use a separate transformer and wiring for accessories that are not tied to the track common.
- If necessary, add some earth ground antennas in the region where there is too much conducted Track signal. Run a wire connected to earth ground on the underside of the bridge or between the parallel tracks, or string some fine wire as power lines on power poles.
- We can temporarily augment the airborne signal by using our body as a secondary antenna, and placing our hand near the locomotive. This brings more earth ground signal to the locomotive. If this helps the locomotive, the permanent fix is to add an earth ground antenna to that area.
