Zones are used for the light commuter rail service that connects to counties external to city limits.
Inside city limits, the distances travelled are so compressed (even interborough), that most trips are less than ten minutes of actual train ride.
Once you start dealing with zones, you also have to start operating on fixed schedules. The New York City system does have time tables but they don't really operate to the minute. The listed times are mostly just targets. More important is the frequency of trains, back to back trains (double capacity) with five minute frequencies during rush hour, and graveyard has 20 minute frequencies, everything else aims for ten minutes between each individual train.
Again, most people are travelling less than 45 minutes on trains set for 30MPH speed limits.
Inside city limits, the distances travelled are so compressed (even interborough), that most trips are less than ten minutes of actual train ride.
Once you start dealing with zones, you also have to start operating on fixed schedules. The New York City system does have time tables but they don't really operate to the minute. The listed times are mostly just targets. More important is the frequency of trains, back to back trains (double capacity) with five minute frequencies during rush hour, and graveyard has 20 minute frequencies, everything else aims for ten minutes between each individual train.
Again, most people are travelling less than 45 minutes on trains set for 30MPH speed limits.
(Manhattan is only 20 miles long)