> Big beefy mag sticks

Thanks for the comments.

Using codes in the track for signal control isn't an option with what I'm considering. I was thinking of a reversing track circuit and using biased-neutral relays at each signal controlled by a set of polar line wires for direction control. Looking at [typical] diagram of two opposing intermediate signals opposite each other at an insulated joint, if the current of traffic is from L to R, the TT would feed to the left of the signals and the TR would receive from the right. When the the directions changes from R to L, the TT would then feed the track circuit to the right of the signals and the TR would receive from the L. There is precedent for reversing track circuits for switches in interlocking, but the switching the TT and TR is between the ends of the same TS. I'm dealing with 1-200' circuits.

I thought AFO circuits had serious problems with inductance problems and attenuation in steel rails.