China has opened a cargo train service linking the eastern city of Yiwu, the world's largest wholesale market for small consumer goods, and Madrid in Spain.

A train with 82 containers was the first to travel the entire course of the "Yixin'ou" cargo line on Tuesday, which starts from Yiwu in coastal Zhejiang Province, enters into Central Asia from western China's Xinjiang and traverses Europe to reach its terminus in Spain.

The 13,000-km line passes six countries apart from China and Spain, including Kazakhstan, Russia, Belarus, Poland, Germany and France. It takes 21 days to travel the entire course of the line, the longest in all China-European cargo railways, officials said.

The line opens a more efficient channel for Yiwu's small commodities to go abroad, with the city previously relying heavily on air and marine transportation, said Lin Jiang, a customs official in Yiwu.

The Yixin'ou rail line opened freight traffic between Yiwu and Central Asia in January.