BERLIN - For centuries, river steamers have plied the Rhine River, and the sound of their whistles has been a symbol of the prosperity of the German city of Duisburg.

Today, the sound of those whistles converges here with the sirens of trains coming from thousands of miles away. Like a cheerful symphony, new vitality is being brought to the city.

Duisburg, Germany's biggest inland port and one of the important slots of China Railway Express, has witnessed fruitful results of the Belt and Road Initiative over the past few years and harvested its own urban economic growth.

Amelie Erxleben, of DIT Duisburg Intermodal Terminal, recently conducted a tour of the terminal, where containers labeled with "China Railway Express" were seen everywhere. Large equipment machines were busy loading and unloading.

"About one third of our business now is related to China," Erxleben said, adding that "around 25 west-and eastbound CRE trains are expected here every week".

DIT, one of the nine large freight yards, is also a main railway container-distribution center in the region. Only four years ago, DIT only handled seven to eight CRE trains weekly.

The soaring business volume makes DIT appear more crowded than ever. Even the road in front of its gate is often congested.

In order to deal with the growth, management of the terminal has recently bought an additional 200,000 square meters of land, according to Erxleben.

Duisburg is on one end of the Chongqing-Xinjiang-Europe rail line, which started operation in 2011 from the southwest Chinese city of Chongqing. In recent years, more and more trains operated by CRE from Zhengzhou, Wuhan, Yiwu, Shenyang and other Chinese cities have been arriving here.

Statistics show that 78 Chongqing-Xinjiang-Europe trains, a year-on-year increase of 66 percent, have been operated since this January. More than 1,000 trains are planned this year.

Chen Si, a native of China's western province of Sichuan, is exploring the huge market brought by CRE trains, together with her husband Klaus Hellmann, a member of the supervisory board of the German logistics company Hellmann.

The transport between Germany and China takes CRE trains approximately 14 days, much faster than by sea and much cheaper than by air. Therefore, it has certain comparative advantages, according to Chen.

"Last year, the total volume of our business by rail from Europe to China amounted to 160,000 metric tons, almost equaling the weight of Cologne Cathedral," said Matthias Magnor, chief operating officer of Road and Rail at Hellmann, during an interview with Xinhua.

CRE trains have made a great contribution to that volume. Meanwhile, the business is growing rapidly, Magnor added.

Many industries have benefited from the Europe-China freight trains.

"For example, the fashion industry - the sales would be very much affected by seasonal reasons. Before the operation of CRE trains, it would take around 40 to 50 days to transport. But now, 14 to 15 days are needed, which will sufficiently ensure the sales," Magnor said.

In fact, when Hellmann began its CRE train business five years ago, some German companies were not very optimistic.

"I managed to persuade them that it is a viable transport option," Hellmann said.

Facts speak louder than words. CRE trains under the Belt and Road Initiative have become the "third pillar" for transportation between Europe and Asia, besides air and sea shipping.

In recent years, Duisburg has also faced the problem of traditional growth momentum decline and is in search of new growth engines. And in this case, the arrival of CRE trains has been just like an old ship opening a new sail, triggering a new boom era in Duisburg.

Johannes Pflug, responsible for China affairs in the Duisburg municipality, said that the volume of the Port of Duisburg grew by 30 percent in 2017, making it the fastest growing port in Germany.

CRE trains play an important role in that growth, and in the more than 6,000 jobs in the area of logistics that have been created, Pflug said.

In Pflug's opinion, the CRE trains achieve a win-win situation for China and Europe. Not only Chinese goods, but also Chinese capital and companies are attracted to Duisburg. More than 100 Chinese companies have so far settled in the region.

"A Chinese company is constructing an 18-story hotel; Chinese company Huawei is responsible for the lighting project of the city," Pflug said.

Soeren Link, the mayor of Duisburg, said CRE trains have brought unlimited opportunities to the city. They bring not only the development of local logistics, but also the improvement of supporting services.