The "Single Document" rail-sea express train service adopts a "Train + Ship + Logistics Contracting" transportation model, where the entire transportation capacity is directly procured by the railway, providing end-to-end services and achieving nationwide reach with a single waybill. Compared to traditional multimodal transportation, the "Single Document" rail-sea express train service features "one-time commissioning, one set of documents, one-time settlement, and direct transport to the destination." It is directly coordinated by the railway authorities throughout the logistics process, reducing negotiations, document exchanges, short-haul transportation, and cargo handling between enterprises and maritime and road transportation sectors, resulting in a 40% increase in transportation efficiency. This train service also utilizes 35-ton new wide-body containers for intermodal transportation by sea and rail. Compared to TEU, these new containers can carry an additional 3 tons of cargo, enabling the entire train to carry over 160 tons of additional cargo.