Columbia subject headings:
Railroads--Economic aspects--Great Britain.
Railroads--Economic aspects--United States.
Railroads--Great Britain--History.
Railroads--United States--History.
Harvard subject headings:
Railroads--Great Britain--History
Railroads--United States--History
Princeton subject headings:
Railroads--Economic aspects--Great Britain.
Railroads--Economic aspects--United States.
Railroads--Great Britain--History.
Railroads--United States--History.