[Oldcodger]

I had a similar problem circa 1983 in Zimbabwe. One of my sites was a highly politically sensitive fuel yard. It was electrically insulated/isolated from the main rail network, but my handbook stated that the resistance from rail to rail and across rail joints must be less than 0,1 ohm. All I could do was to drill the rails and bond over the joints and ( with a large soldering iron heated in the fields outside the yard) connect between rails. No one at rail HQ could suggest a way of verifying that I'd met the standards.