I got bored during the ASU-Wazzu blowout so tinkered around with this:
50 year full build out of Metro Light Rail, Commuter Rail and Intercity rail, thoughts?
I also considered doing an "Orange" line N/S on Scottsdale Rd from Tempe to Scottsdale/101...but who knows if Scottsdale will ever get on board. I figured I was dreaming enough just having transit touch the West side of Downtown Scottsdale.
I also considered an E/W "White" route along Chandler/Williamsfield from Ahwatukee/the I-10 to PHX-Mesa Gateway.
The Central Ave "Rainbow" line would be accessible by most of the other lines. I don't have enough technical knowledge to know exactly how that would work so you wouldn't get train traffic jams along Central though.
In a
super fantasy world, Central from Camelback to Jefferson becomes a subway with multiple lines in it so trains can go express or pass one another.