I just recevied this system for my ho scale model railroad. I understand the bus and the wiring. Except, what to do when I have a shelf layout that terminates on both ends. How do I end the bus? I also need to find out something else. On my command station/booster,db150. There are 2 wire plugins, rail a and b. How do I run the bus off of this? Do I just plug whatever wire I'm using for rail A into it, then the same for rail B. Then follow the rails dropping the feeders in the selected places. Or do I have to have the wires connect into something special and then follow the 2 rails?