I've noticed an uptown 4 train at Union Sq between say 8:10 and 8:25 in the weekday morning (I haven't noted the specific time), that is decidedly less crowded than any other uptown express train. One time, I saw it at Grand Central with almost no standees!

Is there 1 that's turned at South Ferry or perhaps starts elsewhere further up the line?
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Please stand away from the moving platform as trains enter and leave the station. Your safety...