Rail Block Occupancy via Circuit Network

[kc8hnz]

I am messing around with signalling a rail system with a relay style signaling system much like a real railroad and am wondering is there any way to determine a blocks occupancy state besides attacking a wire to a signal? From what I've seen so far if a regular signal shows occupancy, I can attach a output based on its red state. However, I would like to indicate occupancy independently so I can establish a traffic stick path for two way travel on a single rail. I know I can simply use chain signals for the same basic effect, but adding some relay logic in the signalman's fashion could permit less chances of a standoff mid track.

[DaveMcW]

You can use gates as a train detector.