As a clear whistle pierced the morning air, a freight train, carrying maternal and infant products, cosmetics and medical supplies, departed from Duisburg Port in Germany.

The port marked another milestone in enhancing connectivity as this departure on Saturday signaled the launch of the return leg of the ASEAN Express, a freight train service linking Southeast Asia, China and Europe, as well as the beginning of its bidirectional operations.

The train will transfer to Southwest China's Chongqing for reconfiguration before it is expected to arrive in ASEAN countries within 19 days.

The first ASEAN Express departed for Europe in October. The train originally departed from Vietnam's Hanoi, transferred to Chongqing, and arrived in Poland's Malaszewicze for product distribution.

As of now, three routes have been opened, connecting Vietnam, Laos and Thailand to Europe via Chongqing, which serves as the transfer hub.

The service seamlessly connects the New International Land-Sea Trade Corridor, a trade and logistics passage jointly built by China's western provinces and ASEAN members, and the China-Europe freight train service, a hallmark of the Belt and Road Initiative.

Companies now benefit from a unified shipping process that requires only a single order and one bill, in contrast to the previous system, which involved multiple entrustments, separate bills of lading, and repeated loading and unloading, said Liu Taiping, chairman of the New Land-Sea Corridor Operation and general manager of Yuxinou (Chongqing) Supply Chain Management, who spoke at the promotional event for the ASEAN Express following the departure ceremony. Liu said the shipment via the ASEAN Express is approximately 50 percent faster than maritime shipping while costing only about one-fifth of the cost of air freight.

Johannes Philipper, chief operating officer of Rail Germany at Hellmann Worldwide Logistics, a German transport and logistics company that signed a memorandum of cooperation at the event to expand its network via the ASEAN Express, told China Daily that the service bridges established markets and emerging economies, benefiting Germany by supporting the export of its finished vehicles, machinery and medical supplies to ASEAN countries, while bringing back fashion and high-tech products.

Philipper also said the ASEAN Express offers a "perfect and reliable" solution amid the current uncertainty in maritime shipping.

Lars Nennhaus, executive board member of Duisburger Hafen AG, the operator of Duisburg Port, who has witnessed the expansion of the China-Europe freight train service since its launch in 2011, told China Daily the ASEAN Express offers their clients "huge opportunities" for growth.

"The new connection is not only the exchange of goods between countries," he said. "It is an exchange of cultures and people, which will bring countries closer, especially in the times we are living right now."