A glass-bottom sky train of China's first renewable energy-suspension railway demonstration line rolled off in southwest China's Chengdu on June 26. The sky train has glass paneling on three sides, offering passengers on board a stunning 270-degree view. The maximum capacity of one carriage is 120 people. Driven by new energy resources, the sky train is greener and more economical. According to its developer, the train tops out at 80 kilometers per hour and costs only about one-sixth to one-eighth of a regular subway.