Thanks Dale, I found out part of my problem yesterday was after two hours of messing with it, I had an idiot moment and completely forgot the switch position is opposite of the connected circuit. I.E. as you explain when the switch is to the right in the A/B alternate side, you are actually putting out power on the B only middle post through the +12V post on the opposite side.
I've re-verified the switch does as expected, but still ended up with a problem and another question.
Problem: Your drawing shows on the timer relays the connection points attached to the NO part of the relay, but shouldn't the blue wires be attached to the NC? This appears to be the only way I can get it to work, and in my mind makes some sense as the goal of the timer relay is to allow the trolley to pass back over the trigger point without tripping the relays, so when it goes over the point you want the connection broken which would be NC and not NO?
Question: Through testing with the wiring as stated above, I found that if both the trolleys are in the position where IA/IB is on the rail, that the relays just chatter and constantly switch back and forth. So my assumption is the trigger point should be short enough the trolley doesn't stop on it, but long enough where it still makes good enough connection to trip the relays? Also would mean the trigger point needs to be up at the very beginning of the isolated center rail?
Really appreciate all of your help with this! I'm still not as deep in to Arduino with the greenhouse as I would like to be, but pretty confident now with what I know today I could do this in less time that way. I've got to say, the relay logic still has me struggling, we don't do anything like this at work, really only use the relays for high amperage connections with low amp triggers.
