53 Pa. Stat. § 15557
In cases where the city and the owner or owners of lands, rights, and interests therein, property or franchises, to be taken under the powers conferred by this act, cannot agree as to the price or damages to be paid; or where, by reason of the absence or legal incapacity of such owner or owners, or where the owner or owners are unknown, no agreement as to the price or the damages sustained can be agreed upon; the said city may tender its bond, in such penal sum as it may deem proper, to the party claiming or entitled to said moneys or damages, or to the agent of any person absent, or to the guardian or committee of any one under legal incapacity, the condition of which shall be that the said city will pay or cause to be paid such amount of damages as the party shall be entitled to receive, after the same shall have been agreed upon by the parties or assessed in the manner provided by this act: Provided, however, That in case the party claiming damages refuses to, or does not, accept said bond as tendered, the said city shall then give said party a written notice, at least five days beforehand, of a time when the same will be presented for filing in court; and thereafter said city may present said bond to the proper court of common pleas, or to any law judge thereof in vacation, and, if the said bond is approved, it shall be filed in said court for the use of those interested. In case the title to the lands, rights, or interests therein, property or franchises, to be taken as aforesaid, is defective, disputed or doubtful; or the party owning or interested in the same is absent, unknown, not of full age, of unsound mind, or from any cause cannot be bargained with or served with notice, or have a bond tendered to him, her, or them within the county where said lands, rights, or interests therein, property or franchises, are taken; the court of common pleas of the proper county, or any law judge thereof in vacation, upon petition of the said city, setting forth the necessary facts, shall direct the filing of a bond to the Commonwealth of Pennsylvania, in an amount to be fixed and approved by the court, or a law judge in vacation, for the use of those who may be found entitled to the damages for said taking and appropriation; the condition whereof shall be the same as is herein above provided in bonds to be tendered owners when known. Upon the filing and approval of any bond provided for by this section, the respective city shall have the right to enter upon, take, use, occupy, and appropriate the lands, rights or interests therein, property or franchises, mentioned in the bond aforesaid, and the title acquired by virtue of the provisions of this act shall be the fee simple or absolute title.
53 P.S. § 15557