Technological improvements and know-how ensure safe operations in Northeast China's frequent subzero temperatures. 

Although most regions of China have recently started embracing spring breezes, snowstorms still frequently hit Cong Liyan's home in the northeastern province of Heilongjiang.

In the past, winter travel has always been difficult and unpleasant. "Trains were slow and often canceled or delayed by storms, and driving was even harder. Members who live across Heilongjiang and the neighboring provinces of Liaoning and Jilin. Whenever the family gathered for Spring Festival, there were complaints about travel difficulties.

"There was always someone trapped in the traffic and unable to arrive on time,

In Heilongjiang, China's coldest province, the mercury can easily drop as low as-20 C, and sometimes even-30 C, during winter.

Rapid changes

However, things have changed in the past decade thanks to the development of the region's high-speed railway network.

Before this year's Spring Festival, people took a five-hour trip on the bullet train from Beijing to Harbin, a journey that used to take more than 10 hours. Now, in Shenyang, Liaoning's capital, also took a bullet train home, a trip of about two hours.

"The journeys are short, and the trains are always on time. The onboard environment is nice and clean,

The expanding high-speed railway network in China's northeastern region has benefited millions of people.

The three provinces that comprise Northeast China－Liaoning, Jilin and Heilongjiang－are generally the coldest parts of the country, which poses challenges for the construction of the high-speed rail network.

In 2012, four years after the country's first high-speed railway was put into operation, the first high-speed line to operate in extremely cold weather was opened. It connects Harbin with Dalian in Liaoning and links the capitals of the three provinces: Liaoning's Shenyang; Jilin's Changchun; and Heilongjiang's Harbin.

Now, Heilongjiang, the most northeasterly province, has five high speed lines. They connect major cities such as Beijing, the three provincial capitals, and Qiqihar and Mudanjiang in Heilongjiang.

Two of the five lines are China's northernmost and easternmost highspeed railways: the Harbin-Qiqihar and the Mudanjiang-Jiamusi lines.

The number of high-speed railway stations in Heilongjiang has risen from 2 in 2012 to 25, while the network has extended to more than 1,400 kilometers from 94 km.

Transformed, expanded

Before the Harbin-Qiqihar line opened in 2015, Daqing East Railway Station, was called Longfeng Railway Station.

At the time, it had about 30 staff members and two platforms on its roughly 200 square meters, and it handled seven trains a day, with a total of about 1,100 passenger trips.

Since the facility has been expanded and become a bullet train station, it handles 56 arrivals and departures－both bullet trains and regular services－and nearly 7,000 passenger trips every day. The station has expanded to 14,999 square meters, and the customer service department alone employs 140 staff members.

The station's traffic peak occurred during the National Day holiday in October 2019, a few months before the COVID-19 outbreak, when it handled 160,000 passengers, a record for the facility.

Technology and safety

Technology has been adopted in the design of the railways and operation, making China one of the global leaders in the construction of high-speed railways in extremely cold conditions.

An image-collection-and-analysis system has been introduced to help monitor bullet train operations. Cameras have been installed along the tracks to collect images during operation, to identify safety hazards. Technologies, including three-dimensional imaging and image recognition, are applied during the process.

The system assigns images to analysts for examination, which they are required to assess in regular checks, reporting malfunctions if required and calling the on-site workers to handle the problem within 15 minutes of it being noticed.

The average age of the team's analysts is 30, and most of them have bachelor's degrees.

The designers, who have a decade of experience in building high-speed railways, have carried out innovations and gained positive results to ensure that the lines run safely in such low temperatures.

The first challenge in designing a high-speed railway in such conditions is to tackle the problems caused by the constant freezing and thawing of water on the tracks and surrounding areas, according to China Railway Design Corp.

The trackbed freezes, thaws and refreezes repeatedly according to the weather, which can cause it to become uneven and potentially pose a safety hazard. Other issues, such as the resilience of concrete when exposed to extremely cold weather, have also been taken into consideration.

The company's engineers have designed and provided consultation services for several high-speed railways in extremely cold areas, such as the line that connects Mudanjiang and Jiamusi.

China's technology for building high-speed railways in extremely cold weather is ranked in the top-tier globally, which allows passengers to enjoy high-quality journeys and underlines the nation's ability to build similar projects overseas

It added that the country has established a comprehensive technology standard for building high-speed railways in extremely cold areas.