I use a driverless subway almost daily. And it's rare, but not not terribly rare to see the fallback driver panel in use. It works because a fallback driver can

I use a driverless subway almost daily. And it's rare, but not not terribly rare to see the fallback driver panel in use. It works because a fallback driver can be deployed in minutes, which is very much not true with the distances spanned by heavy rail. Regarding the L train, how much would service suffer if the "supervisor" wasn't there to clean up whatever is left by reliability nines? We may never know. And it is hardly surprising that a recently modernized line is beating the living history museum that is the rest of the MTA. It's quite a leap to go from modernization causing reliability to automation causing reliability.