On the morning of June 5, after more than 900 days and nights of round-the-clock efforts by the builders, the final face at the foremost end of the tunnel was successfully breached, marking the safe breakthrough of the Daqingshan Tunnel on the Chongqing-Kunming High-Speed Railway.

The Daqingshan Tunnel is a key control project on the Yunnan section of the Chongqing-Kunming High-Speed Railway and is currently the longest tunnel to have been holed through, laying a solid foundation for the opening and operation of the entire line. The Chongqing-Kunming High-Speed Railway is a key component of the Beijing-Kunming corridor of the national "Eight Vertical and Eight Horizontal" railway network, with a total length of 699 kilometers, of which the Yunnan section is 388.6 kilometers long. As the first high-speed railway in Yunnan Province designed for a speed of 350 kilometers per hour, once the entire line is completed and opened to traffic, the travel time from Chongqing to Kunming is expected to be shortened from the original 5 hours to as fast as about 2 hours.