KUNMING, March 13 (Xinhua) -- The construction of a 17.44-km-long tunnel on the China-Laos railway was completed Friday in southwest China's Yunnan Province, according to the China Railway Kunming Group Co., Ltd.

Wanhe tunnel, with a designed speed of 160 km per hour, is expected to open to traffic in 2021, said the project's construction contractor.

Construction of the tunnel started in April 2016. It is one of the most challenging projects for the railway between China's Kunming and Vientiane of Laos, said Gong Qingwu, head of the project.

The railway is an important project between the two countries under the Belt and Road Initiative. Its construction started in December 2016 and is scheduled to be completed in December 2021.