BEIJING -- With a grand arch bridge erected on Monday morning across the Nujiang River in southwestern China's Yunnan province, Chinese constructors have built the world's longest-spanning railway arch bridge.

The bridge measures 1,024 meters long and nearly 25 meters wide. With a single span of 490 meters, it can accommodate the parking of four trains at the same time, said Yu Changbin, a project manager with China Railway Construction Corporation.

"As the bridge is situated in the gorge of the Yunnan-Guizhou Plateau and affected by a high-intensity seismic belt, it was much more demanding in both breadth and bearing capacity than ordinary railway bridges," Yu said. "There is no precedent for building such a huge bridge station."

To complete the bridge, constructors had to assemble 800,000 bolts, and 922 steel poles of various models weighing 100 tonnes each in the air -- about 230 meters above the Nujiang River.

"The technical difficulty and risks are both very rare," Yu said.

The bridge is a key project of the 220-km-long Dali-Ruili railway which is a key section of the China-Myanmar international railway corridor linking Kunming, the provincial capital of Yunnan, with Yangon, the capital of Myanmar.

Upon completion of the Dali-Ruili railway, the transport time between the two cities will be cut from six hours to two.