Whenever public lands of the United States have been or may be granted to any railroad company for use as a right of way for its railroad or as sites for railroad structures of any kind, and use and occupancy of said lands for such purposes has ceased or shall hereafter cease, whether by forfeiture or by abandonment by said railroad company declared or decreed by a court of competent jurisdiction or by Act of Congress, then and thereupon all right, title, interest, and estate of the United States in said lands shall, except such part thereof as may be embraced in a public highway legally established within one year after the date of said decree or forfeiture or abandonment be transferred to and vested in any person, firm, or corporation, assigns, or successors in title and interest to whom or to which title of the United States may have been or may be granted, conveying or purporting to convey the whole of the legal subdivision or subdivisions traversed or occupied by such railroad or railroad structures of any kind as aforesaid, except lands within a municipality the title to which, upon forfeiture or abandonment, as herein provided, shall vest in such municipality, and this by virtue of the patent thereto and without the necessity of any other or further conveyance or assurance of any kind or nature whatsoever: Provided, That this section shall not affect conveyances made by any railroad company of portions of its right of way if such conveyance be among those which have been or may after March 8, 1922, and before such forfeiture or abandonment be validated and confirmed by any Act of Congress; nor shall this section affect any public highway on said right of way on March 8, 1922: Provided further, That the transfer of such lands shall be subject to and contain reservations in favor of the United States of all oil, gas, and other minerals in the land so transferred and conveyed, with the right to prospect for, mine, and remove same.