SHENYANG — As a bone-chilling cold front swept across northern China, bringing blizzards and temperatures as low as — 30 C in some northeastern regions last week, the country's vast high-speed rail network continued to slice through the frozen landscapes.

The world's largest high-speed railway system, the backbone of modern Chinese mobility, is able to ensure such reliability and comfort amid extreme conditions thanks to having a few tricks up its sleeve.

These tricks 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, 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 said.

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 wearing thermal underwear.

For more vulnerable spots like drain outlets, electric heating tape is 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.

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

The G8111 service, running from Dalian in Liaoning province to Changbai Mountain in Jilin province is operated by the Fuxing high-speed train model CR400BFGS, which is designed to run stably at temperatures as low as — 40 C.

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

A major challenge in snowy regions is the buildup of ice and snow sucked beneath the train at high speeds.

The train cabin's ventilation grilles have 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 for China Railway Shenyang Group Co.

Behind this winter-readiness 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 4.6 billion passenger trips in 2025, a year-on-year increase of 6.7 percent.

The importance of these technologies is 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.

Xinhua