On the Metro I was introduced to "pushers". These were very different from the pushers I knew from the New York City subway. These pushers dressed in uniforms, almost like police, and wore white gloves. At the platform, everyone lined up according to marks on the floor, in double file, one line on either side of the subway car door. When the subway train arrived, it stopped exactly on its mark, the doors opened, and a stream of people poured out between the two lines of awaiting travelers. Once the car had expunged its passengers, the two lines of people would stream into the car. As the car became full, the pushers went to work. They would gently, and very politely, push you further into the car, and push the next person in behind you. When the car was nearly fully to overflowing, the pushers would push the next person in, keeping their hand firmly on the back of the last passenger until the doors started to close. Just as the door was about to close on their arm, the pusher would pull their arm out. Not unlike the way my wife packs a suitcase.
As you can imagine, the Metro trains are crammed with people. At one point, two of us missed a stop because we were pushed to the middle of the car, pinned in the crowd, and unable to make our way to the doors for our stop. Of course, I never felt claustrophobic in the subway cars; most of my American coworkers were over 6 feet (1.8m) tall and their heads poked up above the crowd.