All moneys received pursuant to the provisions of this chapter, whether as proceeds from the sale of revenue bonds or refunding bonds or as revenues, shall be deemed to be trust funds to be held and applied solely as provided in this chapter. The Authority shall, in the resolution authorizing such bonds or in the trust agreement securing such bonds, provide for the payment of the proceeds of the sale of the bonds and the revenues to be received to a trustee, which shall be any trust company or bank having the powers of a trust company within or without the Commonwealth, who shall act as trustee of the funds, and hold and apply the same to the purposes of this chapter, subject to such regulations as this chapter and such resolution or trust agreement may provide. In the case of the proceeds of the sale of revenue bonds or revenues, the trustee may invest and reinvest such funds pending their need for the construction of the project in securities that are legal investments under the laws of the Commonwealth for funds held by fiduciaries. In the case of the proceeds of the sale of refunding bonds, the trustee may invest and reinvest such funds in direct obligations of, or obligations the principal of and the interest on which are guaranteed by, the United States of America. Such money and the interest, income and profits, if any, earned on such investment, shall be available for the payment of all or any part of the principal, interest, and redemption premium, if any, of the bonds being refunded. The proceeds of the sale of refunding bonds shall be so invested and applied as to assure that the principal, interest, and redemption premium, if any, on the bonds being refunded shall be paid in full on their respective maturity, redemption or interest payment dates. After the terms of the trust have been fully satisfied, and carried out, any balance of such proceeds and interest, income and profits, if any, earned or realized on the investments thereof may be returned to the Authority for use by it in any lawful manner.