Summary：The Chinese authorities said it was particularly challenging to construct a line that would operate not only at -40C in winter, but at temperatures of up to 40C in the summer.

A HIGH-speed railway that can run at nearly 350km/h in temperatures of -40C has begun a trial operation in China, ahead of a launch at the end of the year.

Believed to be the only train in the world capable of such speeds in frozen conditions, it will run on a new line that links Dalian, a port city on China's North East coast, to Harbin, which is blanketed by snow for much of the winter.

The new trains will cut the journey time on the 917km line from nine hours to just three-and-a-half.

The Chinese authorities said it was particularly challenging to construct a line that would operate not only at -40C in winter, but at temperatures of up to 40C in the summer.

"We researched high-speed railway line construction in relatively cold areas of Germany and Japan and learned from water and electricity supply projects in frigid areas," said Zhang Xize, the chief engineer of the railway, to the China Daily.

He said the ice could disrupt the train's power supply and signals system, but vowed that every possible safety measure had been taken.

In July 2011, two high-speed trains crashed outside of Wenzhou after the first train lost power, killing at least 40 people and injuring nearly 200.

Since the crash, China has scaled back its high-speed rail project. But the need to boost the Chinese economy has seen the number of approved high-speed rail projects rise again in the second half of this year.

The north east is one of China's key industrial bases, and the train will also help to boost tourism, especially to Harbin's winter Ice Festival.