Hi Shane,
I've never used the "parent/child" rule combination, so I spent some time in the TRS06 Session and Rules Guide. I've been experimenting with the Trigger Check/Ordered List/Set Junctions configuration, and I've gotten it to work with one train coming from one direction. I will also try it as you suggested using the Check Trackside rule.
You've made me fire up some long-unused neurons! I may even remember where I put my keys.
Thanks again.
Art