CBS-- The famous layout built by Tony Lash used the method you described. It used Gargraves track with DCS on the center and one outside rail, with the other rail used in a working signal system (indications only). His longest block with working DCS signal end-to-end was 135 feet. There were actually two at 135; one was end-fed, and the other center-fed. The total blocks were 20, and the longest-- 178 feet and end-fed-- had signal loss for an unknown distance at its far end. It was in a covered level in that area.
I may post a fuller description in another thread, time permitting, as the wiring had some unique features which clearly offset the otherwise reduced traction power transmission of the track. I will post a note here if I do so. Tony was kind enough to spend a weekend afternoon explaining all this to me. Being in a commercial building, he had it wired by an electrician.
--Frank
