SHENYANG, March 3 -- Construction has begun on a high-speed railway linking the Chinese capital of Beijing and Shenyang, capital of northeast China's Liaoning Province, local authorities announced on Monday.

Work on the 8.8-km Sanleng Mount Tunnel started on Feb. 28 to spearhead the Beijing-Shenyang railway project, according to a statement from the provincial transportation department.

The tunnel will stretch from the city of Beipiao to Fuxin Mongolia Autonomous County. It will be completed within 33 months, the statement said.

The 709-km Beijing-Shenyang railway project is expected to be finished within five years, after a total investment of 124.5 billion yuan (20.4 billion U.S. dollars).

The railway, designed with a speed of 350 km per hour, will halve the travel time between the two cities to 2.5 hours, according to the provincial transportation department.

China's railway network topped 100,000 km as of late December, according to the China Railway Corporation, as several new high-speed links started operations in January 2014.

The newly opened links include the Xiamen-Shenzhen railway, the Xi'an-Baoji railway, the Chongqing-Lichuan railway, and others in southwest China's Guangxi Zhuang Autonomous Region. They have a combined distance of 2,000 km.

Of the 100,000 km of track, more than 10,000 km are high-speed, according to official statistics.