Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

A worker is seen on the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province, March 14, 2019. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Workers are seen on the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province, March 14, 2019. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)

Aerial photo taken on March 14, 2019 shows the Yachihe Bridge of the Chengdu-Guiyang high-speed railway under construction in Qianxi, southwest China's Guizhou Province. The construction of the Yachihe Bridge of the Chengdu-Guiyang high-speed railway will be completed by the end of 2019. (Xinhua/Liu Xu)