You catch the wave of people exiting and extricate yourself from the crowd before the next gush of outbound travelers sweeping into the traincar. You catch your breath against the railing, holding tight against the tides of the crowd. looking down over the railing you see a swirling mass far below you, all bubbling up or down from beneath for another pair of rail lines, one of the undergrounds. Across the atrium is the other half of the line you've just deboarded, pointed west back the way you came. Out of the huge half-ceiling window is a towering structure scraping up into a thick layer of fog. A dove is perched on a thickly coiled metal wire that connects two pieces of the ceiling together.