Iowa Code § 558.9
Every railroad company which owns or claims real estate in this state, granted by the government of the United States or this state to aid in the construction of its railroad, where it has not already done so, shall place on file and cause to be recorded, in each county wherein the real estate granted is situated, evidence of its title or claim of title, whether the same consists of patents from the United States, certificates from the secretary of the interior, or governor of this state, or the proper land office of the United States or this state. Where no patent was issued, reference shall be made in said certificate to the Acts of Congress, and the Acts of the legislature of this state, granting such lands, giving the date thereof, and date of their approval under which claim of title is made.
Iowa Code § 558.9