I work for a railroad. We had a situation where two of the metel monkeys got their "work" leads all tangled up and just grabbed a clamp and stuck it to the locomotive they were welding on. They were working on seperate tracks in the same building. When the leads got straightened out, sure enough the "work" leads were backwards, so the welding current was going through the locomotive, into the track, out to the switch where the tracks came together, and back up to the correct lead. Figured that the ground path was just short of a quarter mile long. [Linked Image]
Fortunatly for them, at 10 tons per axle, there was enough weight on the bearings that no damage was done to them as the electricity tried to find its way to the track.
Trainwire