Construction began Tuesday on a second railway connecting Manzhouli, the main crossing on the Sino-Russian border, and Hailar city in north China's Inner Mongolia Autonomous Region.

The project will create a dual track for the entire length of the century-old trunk line linking Manzhouli and Harbin, capital of northeast China's Heilongjiang Province. A dual track forms the Harbin-Hailar section of the 934-km line.

The existing railway between Manzhouli and Hailar had only a single track, said Yu Guangji, administrative leader of Manzhouli Railway Station.

"The single line between Manzhouli and Hailar has become a bottleneck for the development of Manzhouli crossing," said Yu.

With a budget of 1.8 billion yuan (US$222 million), the project will have a length of 178 km and will take 18 months to complete.

The crossing's annual cargo handling capacity is expected