Columbia subject headings:
Amazon River Region--History.
Railroads--Amazon River Region--History--20th century.
Technology--Social aspects--Amazon River Region--History--20th century.
Harvard subject headings:
Amazon River Region--History.
Railroads--Amazon River Region--History--20th century.
Technology--Social aspects--Amazon River Region--History--20th century.
Princeton subject headings:
Amazon River Region--Colonization--History.
Ferrovia Madeira-Mamoré--History.
Technology--Social aspects--Brazil.