Columbia subject headings:
Harvard subject headings:
Railroads--Argentina--History--19th century.
Railroads--Brazil--History--19th century.
Railroads--Uruguay--History--19th century.
Princeton subject headings:
Railroads--Argentina--Monte Caseros--History.
Railroads--Brazil--Barra do Quaraí--History.
Railroads--Uruguay--Bella Unión--History.