The 宿迁市新闻网记者bullet train No.G1276, the first themed high-speed train of the Harbin Ice-Snow World, departs from Harbin West Station in Harbin, northeast China's Heilongjiang Province, Jan. 4, 2026. (Photo by Liu Yang/Xinhua)

by Yi Ling and Wu Jiangmin

SHENYANG, Jan. 22 (Xinhua) -- As a bone-chilling cold wave sweeps across northern China, bringing blizzards and temperatures plunging to minus 30 degrees Celsius in some northeastern regions this week, the country's vast high-speed rail network continues to slice through the frozen landscapes.

How does the world's largest high-speed railway system, a backbone of modern Chinese mobility, ensure such reliability and comfort amid extreme winter? The secrets lie in an array of smart, cold-defying technologies, ranging from giving trains "down jackets" to equipping them with "heating patches."

"Take the Fuxing bullet train as an example. Though its body is exposed, it essentially wears a thick 'down jacket,'" said Wang Xiaoyu, an engineer at China Railway Shenyang Group Co., Ltd, referring to the high-performance insulation materials encasing the train's body. With extremely low thermal conductivity, this specialized barrier effectively blocks frigid outside air.

Complementing this is exquisite sealing craftsmanship. Every door, window and joint of the train carriage undergoes special treatment to achieve a tight fit, drastically reducing heat loss, Wang explained.

But the protection extends far beyond the outer shell. Beneath and atop the train, a network of pipelines for water, air and drainage is wrapped in insulating layers -- akin to being dressed in "thermal innerwear" -- that are thick and effective at locking in warmth.

For more vulnerable spots like drain outlets, electric heating tapes are installed. "These act like 'heating patches,' automatically switching on when sensors detect temperatures dropping too low," Wang added.

Maintaining a steady, pleasant cabin temperature while external conditions fluctuate rapidly is another critical task.

Temperature sensors at both ends of each carriage constantly monitor the indoor climate. Data feeds into an intelligent climate-control system, which automatically adjusts the air conditioning to keep the cabin temperature within a comfortable range, the engineer said.

Additional warmth is delivered through heating vents located along the sidewalls beneath the windows, ensuring passengers feel cozy from head to toe.

A staff member conducts maintenance work at a high-speed train base in Beijing, capital of China, Jan. 20, 2026. (Xinhua/Li An)

China's cold-resistant technological portfolio has continued to expand.

The G8111 train, running from Dalian in Liaoning Province to Changbai Mountain in Jilin Province, for instance, is operated by the Fuxing high-speed train model CR400BF-GS, which is designed to run stably at temperatures as low as minus 40 degrees Celsius.

Key components, from electrical elements to the bogies, braking and air supply systems, have all been re-engineered with special low-temperature resistance.

A major challenge in snowy regions is the buildup of ice and snow sucked beneath the train at high speeds. So, the train cabin's ventilation grilles employ a V-shaped sealing design that effectively prevents snow and ice intrusion during operation.

"Even the cab windows are equipped with anti-fog functions to ensure a clear view for drivers," said Qu Zhengxin, a high-speed train driver at China Railway Shenyang Group Co., Ltd.

Behind this winter-ready prowess stands a transportation giant that carries billions annually. According to official data released by the National Railway Administration on Jan. 15, the country's railways handled a record 4.601 billion passenger trips in 2025, a year-on-year increase of 6.7 percent.

The importance and pressure of these technologies are most evident during the annual Spring Festival travel rush, or chunyun, the world's largest human migration. During the 2025 rush, railways alone transported approximately 510 million passengers over a 40-day period.