Workers are seen at the construction site of Shanghai-Kunming high-speed railway in southwest China's Guizhou Province, June 15, 2012. Railway construction in Guizhou witnessed a rapid development during China's 12th Five-Year Plan period. The province's railway mileage has expanded to over 3,000 kilometers till 2015, including 700 kilometers of high-speed railway. [Photo: Xinhua/Ou Dongqu]