Thanks for commenting. There's still at minimum 2000 feet between each train, and track interchanges between most stations even above 59th. Plenty of room for some number of 5 foot long auto cars to be scheduled between the long trains. And congestion pricing and limited scheduling slots during rush hour is kind of a solved problem. But the goal would not be to augment the already efficient routes. Instead to complement for the inefficient routes, in, like, the entirety of Brooklyn and Queens, where most of the time most people have to wait close to 10 minutes for something to come.