China-Laos Railway witnessed the breakthrough of Tunnel Pengshan constructed by China Railway No.8 Engineering Group Co., Ltd., a subsidiary of CREC, recently. It laid a solid foundation for China-Laos Railway to open to traffic. Tunnel Pengshan in Louang Phabang City, Laos, is a 3,487-meter single-track tunnel. It is also the first tunnel longer than 3,000 meters completed in China-Laos Railway in Louang Phabang City. During the construction, the Project Department overcame adverse geological effects, including tectonic denudation, karst mountain topography, and large terrain variation.