On May 31, Train No. 1209, a 16-wagon meter-gauge freight train carrying 496 tons of imported sulfur, surged ahead in passing the Yunnan-Vietnam Railway Bridge located in Hekou Yao Autonomous County of Honghe Hani and Yi Autonomous Prefecture of Yunnan Province, before sweeping through the first railway tunnel at China-Vietnam Border, Hekou Tunnel. The train has been the first to run through the tunnel since its closed-off capacity expansion.
The 56.53m tunnel is near the end of the Yunnan Section of Yunnan-Vietnam Railway. To meet the demands for cross-border transport of freight, and diversify goods of international combined railway transport, China Railway Kunming Group Co Ltd used the maximum clearance for international container transport for the renovation of Hekou Tunnel and made construction plannings. Since May 12, they began the renovation with modern building technologies such as grout injection through perforated pipes into the soil body outside the portal, grout injection through perforated pipes into the lining of the tunnel, chiseling of tunnel linings and bolt mesh spraying.