Columbia subject headings:
Railroads--Freight--Rates--United States.
Railroads--Freight--Rates.
Harvard subject headings:
Railroads and state.
Railroads--Freight--Rates
Railroads--Freight--Rates--Australia.
Railroads--Freight--Rates--Europe.
Railroads--Freight--Rates--United States
Princeton subject headings:
Railroads and state.
Railroads--Freight--Rates.