It*s Monday morning and Tokyo is going back to work. By 8:16 at Shinjuku Station, the world*s busiest, lines of waiting commuters overlap with the people looking to go in the opposite direction. The smell of pastries from a bakery wafts over the stream of people.

As a train approaches platform 2 on Tokyo Metro Co.*s Marunouchi Line, the number 50 appears on a digital sign, indicating the train will stay 50 seconds longer than usual. That*s because the following train, due in two minutes, has been delayed and is already packed. Each 12 seconds of delay adds about 80 people and makes a train 10 percent more crowded, according to Tokyo Metro.

The clock begins to count down and assistant stationmaster Takashi Arai steps onto a wooden dais.