I think this, known as SWER, may be what you’re looking for.
OK, this kinda thing makes absolutely no sense to me. I get the idea of using the earth to complete a circuit, sorta, but we’re talking about dirt and rocks vs. solid copper. How can you do this without losing 99% of your current to resistance?
When you break the circuit, electrons throughout the circuit all stop moving (almost) simultaneously: The signal propagation speed is the speed of light in the wires. But the electrons themselves are still moving very slowly.
Here it comes,
unh,
unh,
unh,
unh, how was that? I didn’t squeeze too hard, I hope.
I’ll read the whole thing after I eat.
And thanks.
Well, the article mentioned that each ground needed to be under 10Ω or so. This is on the Primary (high voltage) side, so the current is relatively low. If the primary was carrying 8A, then you would lose 64* 10 = 640W of power in the ground connection, which is significant, but not huge.
I should have linked to RuralPower.org to start with. It’s the background information by one of the developers of the system. There’s a big PDF (7Megs) which is a scanned document written by Lloyd Mandeno. The system is used extensively in NZ and Australia and other places around the world. The earthing is easier to do in moist climates such as NZ, but obviously does work in drier places as well. Even in Alaska, as long as the earthing is beneath the permafrost, it works. Permafrost has very high resistance, so it does cause problems.
Don’t forget that while dirt and rocks may have high resistance compared to copper, you are talking about a copper wire at most an inch or so across, while the dirt-and-rock “wire” is potentially enormous in effective cross section.
Sorry for the nitpick here, but the word you should use there is “resistivity”. Resistance already takes into account the cross-sectional area; resistivity is an inherent property of the material independent of its shape.
A tesla coil? I’m walking barefoot through the grass, and a power line falls on my head? 
And what are the capacitance and resistance of your average rat? How about the inductance? Does it make a difference if its tail is curled into a spiral? Can we figure out a way to make a radio entirely out of rats? That sounds like a Doper project on a par with the goat cannon, and a real conversation starter if we can make it work.
My theory:
Rats, living largely in the dark, make extensive use of their whiskers in exploring their environment. I would think that a rat, before attempting to climb a third rail, would likely touch it with its whiskers. That would either singe the whiskers or otherwise give the rat a painful, but non-lethal, reason to avoid future contact with a third rail. The same principle might apply to rats’ fur generally – providing them with a semi-insulating coat that makes it less likely that they’ll make good enough contact to suffer a dangerous jolt. None of these are perfect defenses, of course, and you do sometimes hear about rodent-induced electrical fires, but it does provide an explanation of why the rat toll isn’t far higher.
Man. CHUDs, albino alligators, and now ZOMBIE RATS! I am amazed anyone at all survives a NY subway ride.
I think Markxxx needs to re-read his post.
Don’t be sorry. I knew I needed a term that meant that, but didn’t realise it existed, thanks.