All of the 10 tunnels on the Mile-Mengzi high-speed railway in southwest China's Yunnan Province have been drilled through, laying the foundation for the railway's opening next year.

The Dazhuang Tunnel, the last tunnel of the railway, was drilled through on Thursday, according to China Railway Kunming Group Co., Ltd.

The 107-km railway will link the cities of Mile and Mengzi, both located in Yunnan's Honghe Hani and Yi Autonomous Prefecture, and is expected to become operational in 2022.

Passenger trains operating on the railway are due to travel at 250 km per hour.

Upon completion, the railway will connect with the Nanning-Kunming Railway and integrate into southwest China's outbound channel to Vietnam and other Southeast Asian nations.