We were stuffing our stuff into a backpack as the train left 22nd Street at 4:30 this afternoon when the hissing started and the train slowed. All of the people in the bike car stirred; something had happened. The train stopped in the middle of the tunnel, and the conductor came over the PA. He sounded tense. "There is an emergency situation," he said. "We'll be delayed here for some time. Please be patient."......