2. 59th Street Columbus Circle
For those that frequently pass through the Columbus Circle, you’ll notice that the center platform is now used as a walkway connecting the A/C to the 1 train. Brennan explain its origins:
Express trains [on the IND line] opened doors on both sides in rush hours. On the old subway cars, conductors stood between cars to open doors and could do both sides from the same location. On newer cars, conductors had to open doors from an inside cab, and move to the next car to open the other side, so use of the center platform was discontinued in 1981 because it delayed train service at the busiest time of day.
This portion of the platform isn’t used as the crossover and is devoid of the undulating metal barrier: