@Bob posted:This is absolutely correct. The TMCC base is a radio transmitter. It broadcasts a 455 kilohertz radio signal using two halves of an antenna. The outside rail is one half (transmitted by the wire attached to the lug on the command base) and the ground wire in a 3-wire house electrical system is the other half (transmitted by the U-ground pin on the command base power plug).
Your post above mine said, "Common is a good term for our AC powered track. It's not connected to earth ground, unless you install TMCC or Legacy." Our AC track common is NOT connected to earth ground. The track and the earth ground are the two legs of the antenna for the TMCC signal. Connecting these two legs together would prevent them from broadcasting the signal.
I do not want to belabor a point but AC is AC regardless of the voltage. There is in electrical theory a need for the difference in terms between "Neutral" and "Common". If there is no difference Between DC and AC, try running one engine of one kind on the others Electric. It is Neutral because the current goes plus and minus from the Neutral reference point and DC depending on your wiring is either always on the Plus side or Minus side of Common. Just because Our venerable Postwar ZW's have "COMMON" emblazoned on the Back Above the "U" posts does not make it Right. Interesting the Prewar Z's do not have "COMMON" above the "U" post. I have not looked at the various versions of the Modern ZW's.
My Final $.02.
