HARBIN, Sept. 30 (Xinhua) -- An express railway line started operation on Sunday in northeast China, linking the cities of Harbin and Jiamusi in Heilongjiang Province.

The 344-km line, built in a region where the temperature can be as low as minus 40 degrees Celsius in winter, is designed to allow trains to run at 200 km per hour, cutting the travel time to 123 minutes from about 344 minutes, said the China Railway Harbin Group.

Construction of the railway line started in July 2014 as one of the key projects included in China's mid-and-long term railway network scheme. Trials of the railway line were launched in May this year.

China's railway network is expected to hit 175,000 km in length by 2025, compared with 127,000 km of operating tracks by the end of last year.