China’s transportation infrastructure is stretched to its breaking point. The country has the highest number of passenger kilometers in the world, and the rate and distance of travel increases each year. Train lines routinely run at capacity, with passengers crammed into standing-room only cars. Each year, holiday travel periods set world records for the number of people traveling in a given period. In response, the country has built thousands of miles of new roads, railroads, and high capacity transportation infrastructure. This is a look inside the train system as passengers travel amid the crush of the crowd.