delivered the opinion of the Court.
Section 22 of the Act to Regulate Commerce, as amended by Act of March 2, 1889, c. 382, § 9, 25 Stat. 855, 862, provides, among other things,
“ That nothing in this act shall prevent the carriage, storage, or handling of property free or at reduced rates for the United States, State, or-municipal governments, or for charitable purposes, or to or from fairs and expositions for exhibition thereat, . . .” 1
Whether this section should be construed as denying to the Interstate Commerce Commission power to prohibit such reduced rates, even where they result in unjust discrimination or in undue prejudice to interstate commerce is the main question for decision.
On July 29, 1920, the Interstate Commerce Commission authorized a general increase, throughout southern territory, of 25 per cent, in interstate freight rates.
Ex parte 7J¡., Increased Rates, 1920,
58 I. C. C. 220. Thereafter, the Railroad and Public Utilities Commission of Tennessee authorized, for that State, a like increase of intrastate rates. But the following articles (among others) were excluded from this increase: Carload shipments of stone and gravel when for use in building public highways and consigned to federal, state, county and municipal authorities or their
bona fide
agents. To remove the exception, carriers applied to the Interstate Commerce Commission, claiming that the exception produced illegal discrimination against interstate commerce and an undue prejudice
*321
to persons and localities engaged in such commerce. The Commission found such discrimination; and ordered that the intrastate rates on these commodities, also, be increased to the level of the interstate rates.
Tennessee Rates and Charges,
63 I. C. C. 160, 172. On October 21, 1921, the State of Tennessee and its commission brought, in the federal court for the Middle District of Tennessee, this suit against the United States to have the order set aside. The Interstate Commerce Commission, the Nash ville, Chattanooga & St. Louis Railway and two other interstate carriers, intervened as defendants. The case was heard by three judges under the Act of October 22, 1913, c. 32, 38 Stat. 208, 219. A final decree was entered, declaring the order void, and enjoining its enforcement.
Railroad Commission of Wisconsin
v.
Chicago, Burlington & Quincy R. R. Co.,
The argument is, in substance, this: An order of the Interstate Commerce Commission increasing intrastate rates to the level of interstate rates, must rest upon a finding of illegal preference resulting from the relation of intrastate to interstate rates. Preference to governmental shippers is expressly permitted by § 22 of. the act. Hence, a grant of such preference cannot be held to be unjust or *322 unreasonable under §§ 2 and 3. There was no finding that these lower intrastate rates resulted in failure of the intrastate traffic to yield its proper share of the earnings of the carriers. Consequently, the order of the Commission is void. 2 The argument is, in our opinion, unsound.
Every rate which gives preference or advantage to certain persons, commodities, localities or traffic is discriminatory. For such preference prevents absolute equality of treatment among all shippers or all travelers. But discrimination is not necessarily unlawful. The Act to Regulate Commerce prohibits (by §§ 2 and 3) only that discrimination which is unreasonable, undue, or unjust.
Texas & Pacific Ry. Co.
v.
Interstate Commerce Commission,
*323
Section 22 must in this matter, as in others, be read in connection with the rest of the act, and be interpreted with due regard to its manifest purpose.
Robinson
v.
Baltimore & Ohio R. R. Co.,
The grant of a lower rate on road material to a government, engaged in highway construction, may benefit the government without subjecting to prejudice any person, locality or class of traffic. But a lower rate may result in giving to a single quarry within the State all of the governmental business, so that competing quarries and localities within or without the State, or interstate traffic, would be prejudiced. That such undue discrimination does, and will, result from the order of the Tennessee commission was expressly found by the Interstate Com
*324
merce Commission. Its findings are necessarily conclusive, since the evidence on which it acted was not introduced in this suit.
Louisiana
&
Pine Bluff Ry. Co.
v.
United States,
There is nothing in
Interstate Commerce Commission
v.
Baltimore & Ohio R. R. Co.,
Reversed.
Notes
The first line of § 22 as originally enacted, 24 Stat. 379, 387, read, “ That nothing in this act shall apply to the carriage,” etc.
The order of the Interstate Commerce Commission was declared void “ to the extent that the rates therein ordered to be established . . . apply to such transportation, for the United States, State or Municipal governments, of stone and gravel, the title to which has passed to the government or is vested in it at the point of the origin of its transportation.”
See also
Texas & Pacific Ry. Co.
v.
Abilene Cotton Oil Co.,
Section 22 has been construed by the Commission as conferring upon carriers such permission to furnish transportation at reduced rates or free, in certain cases; as not conferring upon any shipper or traveler a right to such transportation; and, ordinarily, as not conferring upon the Commission power to establish such exceptions to the normal rates and fares. Sprigg v. Baltimore & Ohio R. R. Co., 8 I. C. C. 443; Field v. Southern Ry. Co., 13 I. C. C. 298; Metropolitan Paving Brick Co. v. Ann Arbor R. R. Co., 17 I. C. C. 197, 204; Eschner v. Pennsylvania R. R. Co., 18 I. C. C. 60, 63; Dairymen’s Supply Co. v. Pennsylvania R. R. Co., 28 I. C. C. 406; United States v. Union Pacific R. R. Co., 28 I. C. C. 518, 524. See also C. B. Havens & Co. v. Chicago & Northwestern Ry. Co., 20 I. C. C. 156. Compare Cator v. Southern Pacific Co., 6 I. C. C. 113; Commutation Rate Case, 21 I. C. C. 428, 437; United States v. Alabama & Vicksburg Ry. Co., 40 I. C. C. 405. Conference rulings provide, as to some reduced rates under § 22, that they must be filed and posted with the Commission; and as to others that they need not be. See Conference Rulings, Issued Nov. 1, 1917, Nos. 33, 36, 208e, 218, 244, 311, 452.
