Section 13. In the discretion of the corporation such revenue bonds or revenue refunding bonds may be secured by a trust agreement by and between the corporation and a corporate trustee, which may be any trust company or bank having the powers of a trust company within the commonwealth. Such trust agreement may pledge or assign the revenues to be received, but shall not convey or mortgage any project or part thereof.

Either the resolution providing for the issuance of bonds or such trust agreement may contain such provisions for protecting and enforcing the rights and remedies of the bondholders as may be reasonable and proper and not in violation of law, including without limiting the generality of the foregoing provisions defining defaults and providing for remedies in the event thereof, which may include the acceleration of maturities, and covenants setting forth the duties of, and limitations on, the corporation in relation to the acquisition, construction, improvement, enlargement, alteration, equipping, furnishing, maintenance, operation, repair, insurance and disposition of property, the custody, safeguarding, investment, and application of moneys, the use of any surplus bond or note proceeds and the establishment of reserves. Such resolution or trust agreement may also contain covenants by the corporation in relation to, among other things, (a) the establishment, revision and collection of such rents and charges for services of facilities furnished or supplied by the corporation as shall provide revenues sufficient with other revenues of the project, if any, to pay (i) the cost of maintaining, repairing and operating the project and of making renewals and replacements in connection therewith, (ii) the principal of and the interest on said revenue bonds as the same shall become due and payable, (iii) payments in lieu of taxes, betterment and special assessments, and (iv) reserves for all such purposes, (b) the purpose or purposes for which the proceeds of the sale of the bonds will be applied and the use and disposition thereof, (c) the use and disposition of the gross revenues of the corporation from the project, any additions thereto and extensions and improvements thereof, including the creation and maintenance of funds for working capital and for renewals and replacements to the project, (d) the amount, if any, of additional revenue bonds payable from the revenues of the project and the limitations, terms and conditions on which such additional revenue bonds may be issued, and (e) the operation, maintenance, management, accounting and auditing of the project and of the income and revenues of the corporation. It shall be lawful for any bank or trust company incorporated under the laws of the commonwealth to act as depository of the proceeds of bonds or of revenues and to furnish such indemnifying bonds or to pledge such securities as may be required by the corporation. Such trust agreement may set forth the rights and remedies of the bondholders and of the trustee, and may restrict the individual right of action by bondholders as is customary in trust agreements or trust indentures securing bonds and debentures of corporations. In addition to the foregoing, such trust agreement may contain such other provisions as the corporation may deem reasonable and proper for the security of the bondholders. All expenses incurred in carrying out the provisions of such trust agreement may be treated as a part of the cost of the operation of the project. The pledge by any such trust agreement or resolution shall be valid and binding from the time when the pledge is made; the revenues or other moneys so pledged and then held or thereafter received by the corporation shall immediately be subject to the lien of such pledge without any physical delivery thereof or further act; and the lien of any such pledge shall be valid and binding as against all parties having claims of any kind in tort, contract or otherwise against the corporation, irrespective of whether such parties have notice thereof. Neither the resolution nor any trust agreement by which pledge is created need be filled or recorded except in the records of the corporation, and no filing need be made under the Uniform Commercial Code.