China's northernmost high-speed rail line, designed for trains running at speeds of up to 250 km per hour between Harbin and Qiqihar, will go into service by the end of this month, railway authorities in Harbin said.

Construction of the 281-km line, which has eight stops, began in November 2009. Workers overcame numerous problems with snow and frozen land, and topography that required a significant number of bridges.

"The 3,460-meter-long bridge over the Songhua River, which contains four rail lines, is the controlling project of the whole line and lifts the nation's bridge construction to a new level," said Zhang Guohua, the project manager.

At the beginning of construction, the plan was to remove the Binzhou Railway Bridge, which locals call "the old Songhua River Bridge". However, the railway bridge, the first on the Songhua River, is more than 100 years old and already a famous scenic spot.

After review by a cultural heritage protection team, the old bridge was preserved and included in a cultural heritage protection area in Harbin.

As a result, a new Songhua River Railway Bridge was built about 60 meters to the east of the old one, and the two railway bridges spanning the river have created a unique landscape.

The new bridge, which cost 1.4 billion yuan ($225 million), has an expected life span of more than 100 years.

During its construction, builders met many difficulties, such as the region's extremely low temperatures, because freezing causes rail lines to expand, and "is one of the world's toughest problems", Zhang said. "Fortunately, our team attracted a group of young talents and lots of high-speed rail engineering experts. The power of teamwork helped us meet the challenges."

After more than 50 experiments by experts from well-known China colleges and research institutes, project managers found materials that protected the line against expansion in freezing temperatures. After three years' observation, they are confident the problem was solved.

Another serious problem was the bitter cold in Harbin. In the winter of 2010, the lowest recorded temperature was - 40 C, and it's even colder on the Songhua River.

The drilling rig didn't work because of the low temperatures and, even worse, materials such as stones and rebar had to be shipped to the project via the river, which made the construction more difficult.

Some engineers suggested suspending construction until the spring, but Zhang worried about how that would delay the project. After more tests, Zhang and his team solved the problems.

The Songhua River is one of the key waterways in the province. In an effort to protect the environment, more than 350,000 cubic meters of mud mixture generated by drilling was sent into a special sedimentation tank so it would not pollute the river.

The main part of the bridge was finished on Oct 23.

Duan Jixin contributed to this story.

(China Daily USA 08/07/2015 page5)