Empty container repositioning with foldable containers in a river transport network considering the limitations of bridge heights

River-sea intermodal transport is becoming increasingly popular for container repositioning in hinterland areas, owing to its cost-efficiency and low energy consumption. However, bridge heights and water depths may restrict the sailing of container vessels on rivers, which presents a challenge for the wider implementation of river-sea intermodal transport. In this study, we investigate the potential of foldable containers to improve empty container repositioning in river-sea intermodal transport, with consideration of bridge height and water depth constraints. A mathematical model is developed to minimize the total cost. Numerical experiments based on near-practical instances on the Yangtze River in China are conducted to test the effectiveness of the model and the efficiency of foldable containers. The results show that introducing foldable containers into empty container repositioning along a river can utilize vessel space more effectively and decrease the total cost for container shipping companies. The joint impacts of bridge heights and foldable containers on the overall performance are analyzed to obtain managerial insights. Finally, policies are suggested to facilitate the implementation of foldable containers for river-sea intermodal transport.