Dave Zucal posted:Thank you guys. The reason I asked is because when laying track we're told to avoid creating a continuous loop so that we don't have signal collision. If both rails are used, why don't we also avoid loops with the outside rails? If track blocks were totally isolated from each other, would we have better signal communication between the TIU and engine?
It's from transmission line theory like GRJ said.
When you transmit into a loop there's two forward propagating wave-fronts that create an interference pattern with nulls (spots with no signal). If you break one rail of the two (IE the center rail) around the loop then the wave can't propagate through it in both directions and it doesn't really matter if you break the ground or not. For a more analytical explanation maybe browse : Transients on TLines
