Garrett,
check out the link below. This layout had a thread on here a couple years ago. The "Grandpa Russ layout" is essentially the same as your diagram above, only folded over itself.
Two train automation, two reverse loops, and passing siding in between. Automation is accomplished through relays.
He includes a wiring diragram. take a look:
http://corycraft.blogspot.com/...randpa-russ.html?m=1
JD