You're not describing the New York City subway. The L line was separated from pretty much everything else so it got upgraded to CBTC over a few years as budget,

You're not describing the New York City subway. The L line was separated from pretty much everything else so it got upgraded to CBTC over a few years as budget, time constraints, and politics allowed. The rest of the network is thoroughly interwoven and runs 24x7. It also carries more people daily than all the other systems on the continent combined.