I see by my notes that 10 July is Nikola Tesla's birthday.

A comment was made about the 'inductance' of a rail ground.  Maybe.
Measurment would settle it.  BUT.  There exists a body of data (from the
early days of lightning rod development, some in fact from the 1870s...)
that shows that iron wire, at the relavant frequencies, is NOT substantially
more reactive than copper wire.  I've not thought it fully thru, but
presumably this si due to skin effect.  Rail, being large, has lots of
surface area...