delivered the opinion of the Court.
On February 25, 1921, and June 30, 1921, the respondent railroads respectively filed applications with the Interstate Commerce Commission for a readjustment of the compensation for services in carrying the mails rendered by them, from dates before the applications and for the future. The Commission at first expressed an opinion that it had “ authority to establish rates only for the future ” but made orders establishing rates as fair and reasonable after the date of the orders. On further hearings, however, it made new orders establishing the same rates as fair and reasonable for the times between the filing of the applications and the orders previously made. 85 I. C. C. 157. 95 I. C. C. 493. See 144 I. C. C. 675. The railroads applied to the Postmaster General for payment as ordered by the Commission, but their applications were refused. Thereupon they sued in the Court of Claims and got judgments for compensation computed according to the last orders of the Commission. 65 Ct. Cls. 115. The United States asked and obtained a writ of certiorari from this Court.
The ground taken by the United States is that the Interstate Commerce Commission had been given no authority to change the rates of payment to be received by the railroads for any time before its orders went into effect. The question is one of construction which requires consideration not of a few words only but of the whole Act of Congress concerned. This is the Act of July 28, 1916, c. 261, § 5; 39 St. 412, 425-431 (C., Tit. 39, ch. 15, where the long § 5 is broken up into smaller
*78
sections) which made a great change in the relations between the railroads and the Government. Before that time the carriage of the mails by the railroads had been regarded as voluntary,
New York, New Haven & Hartford R. R. Co.
v.
United States,
We assume that while the railroads perform these services and accept pay without protest they get no ground for subsequent complaint.
American Smelting & Refining Co.
v.
United States,
Judgments affirmed.
