Lying among some of China's most mountainous terrain, the cities of Chengdu and Chongqing were once isolated. But a new high-speed railway line has changed that, dramatically reducing travel time between them from 13, to 2 hours. For three generations, train driver Li Zhigang and his family have been witnesses to the evolution of China's rail transport from steam, to high-speed trains. They have seen how the improved connectivity has transformed the economy and lifestyles in the region.