Land bridge transportation means transportation from one seaport to another by railway across continents instead of by ocean ship. A typical Land Bridge in the US is the unit container train crossing the USA from the West Coast to the East Coast.
When Chile won the 1879-1884 War of the Pacific over Bolivia and Peru, Bolivia lost access to the Pacific Ocean. Today, mining products are shipped direct from Bolivia to Chilean seaports by way of unit trains. The trainload is entirely Bolivian property. It has been loaded on Bolivian soil and it will be unloaded in a Bolivian tax-free foreign trade zone located in Portezuelo, Chile, not far from the city and sea port of Antofagasta. This free zone serves as a stockpiling area from where the goods are further shipped overseas as per market demand. All cars belong to the FCAB, a Chilean company, but they are marked "Bolivia" because they are dedicated to this service.
On this picture, such a unit freight train loaded with Bolivian mining products and bound for Portezuelo is travelling south of the Bolivia-Chile border.