In the discretion of the Department, each and any issue of such revenue bonds may be secured by a trust indenture by and between the Department and a corporate trustee, which may be any trust company or bank having the powers of a trust company within or without the State. Such trust indenture may pledge or assign tolls and revenues to be received but shall not convey or mortgage the Bridge or any part thereof. Either the resolution providing for the issuance of revenue bonds or such trust indenture may contain such provisions specifying, defining, protecting and enforcing the rights and remedies of the bondholders as may be reasonable and proper and not in violation of law, including covenants setting forth the duties of the Department in relation to the acquisition, construction, improvement, maintenance, operation, repair and insurance of the Bridge, or additions thereto, and the custody, safeguarding and application of all moneys and may also provide that the Bridge shall be constructed and paid for under the supervision and approval of consulting engineers employed or designated by the Department and satisfactory to the original purchasers of the bonds issued therefor and may also require that the security given by contractors and by any depository of the proceeds of the bonds or revenues or other moneys be satisfactory to such purchasers. It shall be lawful for any bank or trust company incorporated under the laws of this State to act as such depository and to furnish such indemnifying bonds or to pledge such securities as may be required by the Department. Such indenture may set forth the rights and remedies of the bondholders and of the trustee and may restrict the individual right of action of bondholders as is customary in trust indentures securing bonds and debentures of corporations. In addition to the foregoing, such trust indenture may contain such other provisions as the Department may deem reasonable and proper for the security of bondholders. All expenses incurred in carrying out such trust indenture may be treated as a part of the cost of maintenance, operation and repairs of the Bridge to which such indenture is related.