Columbia subject headings:
Railroads and state--United States.
Railroads--Freight--Rates--Law and legislation--United States.
Railroads--United States--Rates.
Harvard subject headings:
Railroads and state--United States.
Railroads--Freight--Rates--Law and legislation--United States.
Railroads--Freight--Rates--United States
Princeton subject headings:
Railroads--Freight--Rates--Law and legislation--United States.