74 Pa.C.S. § 1718

(a) Facsimile signatures.--Whenever the business of the authority requires the affixing of the signature of any officer or employee of the authority, the use of a facsimile signature, when expressly authorized by resolution of the board, shall have the same force and effect as an original signature.

(b) Signatures of officers ceasing to hold office.--In case any officer whose signature appears upon any check, draft, bond, certificate or interest coupon issued under this chapter ceases to hold office before the delivery thereof to the payee or the purchaser of any bond or certificate, the officer's signature, nevertheless, shall be valid and sufficient for all purposes with the same effect as if he had remained in office until delivery thereof.