Ralph
I would have to think a bit and draw it out. Off the top of my head it could be done with 2 reed switches for sure and IR detectors maybe. Basically we are making a circuit for 2 rail. The problem with the IR detector is that when the train is leaving the block the gap between cars makes and breaks the detector as the train moves. There is a timing circuit in the Lionel IR detector I think but if the train stalls in that position it may not be reliable. There is a difference between a block signal not working right and trains colliding if it does not work right so we have to be careful here. If the reed switch failed we would not have a collision.
Anyway I will sketch it out and look in my parts box. Most useful would be a twin coil mechanical latching relay . This would have memory so the trains would not have to be parked on the siding when shut down. I need to know what kind of turnouts you are using. They have to be thrown in tandem.
Even with this since 2 trains are running on a loop the center rail of the 2 siding have to be isolated if they are not now.
For parts we are looking at I think 3 relays,a latch relay and a few rectifiers and 2 reed switches and capacitors. For pause between trains a timer and another relay. Again give me a bit of time. The best laid plans of mice and men sometimes go astray.
Dale H
