Again, just some basic o-scale stuff. Oldschool tubular track with metal ties- both outside rails are shorted together on every piece of track. Only the center rail was typically insulated at each tie.
Fastrack- most pieces contain a shorting bus bar that connects the 2 outer rails much like old tubular.
Atlas, Ross, and Gargraves- natively, few if any tracks natively come with any form of electrical connection between the outer 2 rails. It's up to you the owner and installer to wire them together when doing your power drops.
