John, glad to hear that your kits will be complete with detectors and relays. Good news!
Stan I recall the previous thread and the daisy chaining of two or more detector relays as you show above. I was wondering if that is how it might be done. Thanks for sharing.
I also recall the lengthy thread about 2 years ago regarding use of 153IR's and Itad's for driving interconnected crossing gates, signals and such. I agree that modding a 153IR to isolate the relay common is a bit of a chore considering adding an external relay to the circuit is pretty simple. I wound up creating a small pcb to accommodate a small 2 amp relay for these stuations, and it works quite well. I have also previously used DZ-1008 relays in a couple of similar setups on the layout to drive crossing gate pairs, but they do seem like overkill for driving signals. But hey, they work.
Overall this is a pretty neat project and I hope it continues to generate interest! 
Looking forward to the kits John.
Rod
