China is expected to open its longest high-speed railway in a northeastern area neighboring Siberia.

The 343-kilometer line links Harbin, the provincial capital of Heilongjiang, with Jiamusi, also in Heilongjiang. It has been undergoing tests since Tuesday.

It is designed for both passenger and freight transportation with a speed of 200 km per hour. It will shorten the travel time between Harbin and Jiamusi by train to 110 minutes from about 360 minutes.

Passenger and cargo testing trains were used to examine systems and projects including power supply, subgrades, and bridges to ensure they all meet requirements.

The line is scheduled to undergo a pilot run in July before full operation one month later.

Construction on the high-speed railway started in July 2014 as one of the key projects included in China's mid- and long term railway network scheme. The railway is entirely located in a high-altitude cold area, which is challenging both for builders and future train operators. Local temperatures can dip to minus 35 degrees Celsius in winter.