A thought occured to me while thinking about CBTC in relation to the R-211's.
With Culver and 8th Avenue nearly Wrapping Up and going online in the near future, and QBL East on the way, it not only makes a lot of sense as to why Fulton, Crosstown and 6th Avenue were chosen, but at that point, a good portion of the IND will already be CBTC Active by the time the 211 order is finished. Since the IND Rockaway Line was planned under Fast Forward, Installing CBTC there, along with the Concourse, CPW and IND Archer Avenue Branch (over 7th, Lex, Astoria and Broadway) would not only ensure the and would be complete (the being 1 stop short of being complete), but would also ensure that the IND would be fully automated. Maybe that could make CBTC Installation easier for the rest of the system.