It is a maxim of common law that transportation charges must be
reasonable, and the exaction of an unreasonable rate by a public
carrier is a common-law misdemeanour punishable by the courts. But
when, as the result of severe competition of railroads with waterways
and with each other, unjust discriminations between persons, between
places, and as regards classes of traffic--the abuses which constitute
the railway question--became prevalent, the common-law provisions
applying to railway charges were given statutory form and were
supplemented and extended by such legislation as the circumstances
peculiar to the situation seemed to demand. The comprehensive
railway- and canal-traffic act passed by Great Britain in 1854 has
been the model adopted for much of the railway legislation in the
United States.
The Constitution of the United States gives Congress power to regulate
commerce "among the several States," but the jurisdiction over
intrastate traffic lies with the State governments. The States began
to pass general laws for the regulation of railroads fully twenty
years before Congress acted, and two thirds of the States have
established commissions to administer those laws.