African and Australian Railroads.—In Africa no east and west transcontinental line has yet been finished. In Australia the only one was completed in 1917. It runs east and west along the soutern coast and connects the active southwestern corner of the continent with the prosperous southeastern part by crossing a barren desert over a thousand miles wide. In South America one railroad crosses the narrow southern part of the continent. It surmounts the great difficulties of the Andes in order to connect the two progressive regions of Argentina and Chile, just as for similar purposes the North American transcontinental lines surmount the Rockies and Sierras, while the Trans-Siberian road overcomes the great difficulties of enormous distance (see Fig. 29).
North and South Railroads.—Along north-and-south lines no great trans-continental lines have yet been finished in any of the continents except Europe. The greatest of such roads will be in Africa and America. Their purpose, like that of the other great roads, will be to connect highly advanced centers which in their case are on opposite sides of the equator. In Africa the Cape to Cairo Railway is well
under way along the east side of the continent between the prosperous British colonies of Egypt and South Africa. It follows the Nile to the Great Lakes of Central Africa and then continues southward along the plateau. The other great north-and-south railroad will some day run from the United States through Mexico to Brazil, Argen tina, and Chile, but as yet it is only a project. The increasing growth of the southern countries is rendering it more and more neces sary. When it is built it can scarcely follow the difficult Andean highland, but must probably make its way along the plains. Africa has an advantage over South America in this respect, for its north and-south railroad can follow the broad plateau and thus cross the torrid zone in a comparatively healthful region, while the American highlands are so lofty that the railroad will probably be forced to seek the densely forested, unhealthful lowland.