Argument for Defendant in Error. 231 U.S. franchises where the power is reserved has been frequently sustained. See Miller v. State, 15 Wall. 478, 498; Holyoke v. Lyman, 15 Wall. 500, 519; Tomlinson v. Jessup, 15 Wall. 454, 459; Railroad Company v. Maine, 96 U. S. 499, 510; Shields v. Ohio, 95 U. S. 319, 324; Sinking Fund Cases, 99 U. S. 700; Calder v. Michigan, 218 U. S. 591; Looker v. Maynard, 179 U. S. 46, 52. In applying the law as laid down by this court no vested right has been impaired, or contract obligation violated; nor has there been any attempt on the part of Congress to pass a law, which would permit the taking away from the railroad company any portion of its right of way which had been put by it to its corporate uses. Considered as a retrospective act it was intended by Congress as such, and contravenes no constitutional provision. The construction contended for by counsel for plaintiff in error, that it operates only prospectively, makes an almost absurd situation. At any time within the next ten to twenty years, depending upon the statutes governing adverse possession in the various States, the railroad company may go into court and recover possession of the original four hundred foot right of way, exclusive of the one hundred feet now in use, and those interests which are thereby affected are without standing in court, and have no defense which may be maintained. Such a construction would clearly be against the public interest, and the act itself would avail nothing, except a notice to the railroad that it must within the succeeding twenty years proceed to take some action against those interests which have been occupying certain portions of this right of way unforbidden by the company or assented to by it. A retrospective law is not in itself unconstitutional. Satterlee v. Matthewson, 2 Pet. 380, 413; Curtis v. Whitney, 13 Wall. 68, 70; Charles River Bridge Case, 11 Pet. 420, 510; Watson v. Mercer, 8 Pet. 88, 110; Balt, & Susq. R. R. 231 U. S. Argument for Defendant in Error. Co. v. Nesbit, 10 How. 395, 401; Blount v. Windley, 95 U.S. 173, 180; Calder v. Bull, 3 Dall. 386, 391. Laws retrospective in their nature do not offend against the Constitution, but have frequently been held to be beneficial in their nature, and to operate for the general good of the community. United States v. Un. Pac. R. R. Co., 160 U. S. 1, 33; Munn v. Illinois, 94 U. S. 113, 134. The question of vested rights is closely associated with the question of the enjoyment of contracts, which are guaranteed by constitutional provision; and as to what may be considered within the scope of legislative powers, so far as impairing contract obligations under constitutional restriction is concerned, the field is very broad. Spring Valley Water Works v. Schottler, 110 U. S. 347; Morley v. Lake Shore Ry. Co., 146 U. S. 162; Curtis v. Whitney, supra. It is evident that the act in controversy was passed by Congress for the public good, and while in a way it might be said to enhance the difficulty of performance, in that in the far distant future the railroad company might have use for a right of way four hundred feet in width, and yet the contract between the Government and the railroad in the nature of its original charter and grant remains in full force by virtue of the terms of the act guaranteeing to the railroad a right of way not less than one hundred feet in width. Pearsall v. Great Northern R. R. Co, 161 U. S. 646, 673. The act of the legislature absolutely forbidding the exercise of powers originally granted to the corporation, was sustained in the interest of the public, where those powers remain unexecuted. In the case at bar Congress has enacted a law in the interest of the public diminishing the grant to the Pacific Railroad Companies from a right of way as originally granted of four hundred feet to a right of way as amended of one hundred feet, but only as to those portions of the original right of way outside of the one hundred foot width which have remained unused by the companies for long periods of time. L. & N. R. R. Co. v. Kentucky, 161 U. S. 677, 700. MR. JUSTICE MCKENNA delivered the opinion of the court. Ejectment to recover certain described lands alleged to constitute part of the right of way of plaintiff (being such in the court below, we will so call it). The allegations of the complaint are that plaintiff and defendant are corporations, and that plaintiff is engaged in the operation of a railroad from Ogden, in Utah, easterly through certain States to Council Bluffs, Iowa, and over the lands in controversy, they being portions of its right of way made by the act of Congress of July 1, 1862, c. 120, 12 Stat. 489, of the width of 400 feet. The right of way was acquired under said act of Congress, which is entitled "An Act to aid in the construction of a railroad and telegraph line from the Missouri River to the Pacific Ocean, and to secure to the government the use of the same for postal, military and other purposes." Section 2 of the act provides as follows: "That the right of way through the public lands be, and the same is hereby, granted to said company [the Union Pacific Railroad Company] for the construction of said railroad and telegraph line; and the right, power, and authority is hereby given to said company to take from the public lands adjacent to the line of said road, earth, stone, timber, and other materials for the construction thereof; said right of way is granted to said railroad to the extent of two hundred feet in width on each side of said railroad where it may pass over the public lands, including all necessary grounds for stations, buildings, work-shops, and depots, machine shops, switches, sidetracks, turntables, and water stations." By virtue of said act of Congress and amendatory acts, certain railroad companies, which are enumerated, theretofore organized and existing in pursuance of said acts and subject to and enjoying the rights created thereby, were consolidated into a new corporation known as "The Union Pacific Railway Company," and the corporation thus created became vested with all the rights of the said constituent corporations, and the plaintiff has become the successor of the Union Pacific Railway Company and is entitled to the possession of the land in controversy and that defendant wrongfully keeps it out of the possession thereof. The ground of the asserted right of defendant is alleged to be an act of Congress entitled "An act legalizing certain conveyances heretofore made by the Union Pacific Railroad Company," approved June 24, 1912, c. 181, 37 Stat. 138, which act, it is alleged, is unconstitutional in that it seeks to deprive plaintiff of its vested rights and titles in and to the lands and to deprive it of its lands and property without due process of law. The answer of defendant admits all of the allegations of the complaint except the possession of the legal title to the lands in plaintiff and that they are unlawfully held from it and alleges that defendant and its immediate grantors have been for more than ten years prior to the filing of the complaint in the adverse possession thereof under the act of Congress of June 24, 1912, and that such possession constitutes a bar to the action. Plaintiff demurred to the answer as not constituting a defense. The demurrer was overruled and, plaintiff declining to plead further, judgment was entered that it take nothing in said action" and that the defendant have and recover costs. This appeal was then prosecuted. The crux of the controversy is the act of June 24, 1912. There is no question of the grant of the right of way and its extent or that the lands in suit are within it. The act provides that all conveyances and agreements heretofore made by the enumerated railway or railroad companies "of or concerning land forming part of the right of way" under the act of Congress of July 1, 1862, "and all conveyances or agreements confining the limits of said right of way, or restricting the same, are hereby legalized, validated, and confirmed to the extent that the same would have been legal or valid if the land involved therein had been held by the corporation making such conveyance or agreement under absolute or fee simple title. "That in all instances in which title or ownership of any part of said right of way heretofore mentioned is claimed as against said corporations, or either of them, or the successors or assigns of any of them, by or through adverse possession of the character and duration prescribed by the laws of the State in which the land is situated, such adverse possession shall have the same effect as though the land embraced within the lines of said right of way had been granted by the United States absolutely or in fee instead of being granted as a right of way." Two contentions are made by plaintiff, (1) The act is not retroactive; (2) If it be so construed, it is unconstitutional because it takes plaintiff's vested right and title to the property and transfers the same to defendant without due process of law. It is established that the right of way to the several railroads was a present absolute grant, subject to no conditions except those necessarily implied, such as that the roads should be constructed and used. And it has been decided that the right of way was a very important aid given to the roads, (Railroad Company v. Baldwin, 103 U. S. 426; Stuart v. Union Pacific Railroad Co., 227 U. S. 342), and that it could not be voluntarily transferred by the companies nor acquired against them by adverse possession. Northern Pacific Railway Co. v. Townsend, 190 U. S. 267; Northern Pacific Railroad Co. v. Smith, 171 |