Columbia subject headings:
Communication--United States.
Urban transportation--United States.
Harvard subject headings:
Cities and towns--Transportation--United States.
Cities and towns--United States.
Communication and traffic--United States--History.
Telecommunication systems--United States--History.
Urban transportation--United States--History.
Princeton subject headings:
Cities and towns--Transportation--United States.
Cities and towns--United States.
Communication and traffic--United States--History.
Telecommunication systems--United States--History.
Urban transportation--United States--History.