Our subway system is a marvel of old school infrastructure. The oldest section is almost 110 years old! And the technology of subway service really hasn't changed much in that time. The trains are not controlled by computers but by two dedicated civil servants. One who drives the train from the front, and the conductor in the middle car who opens the doors and makes announcements. When a train pulls in, a striped board hanging from the ceiling tells the conductor the train is correctly stopped in the station. But to be extra sure, the MTA requires the conductors to actually POINT at the board, so that they don't get lazy and forget to look. So someone thought of some fun to have with this regulation.