In the discretion of the authority any revenue bonds issued under the provisions of sections 136A.25 to 136A.42, may be secured by a trust agreement by and between the authority and a corporate trustee or trustees, which may be any trust company or bank having the powers of a trust company within the state. Such trust agreement or the resolution providing for the issuance of such revenue bonds may pledge or assign the revenues to be received or proceeds of any contract or contracts pledged and may convey or mortgage the project or any portion thereof. Such trust agreement or resolution providing for the issuance of such revenue bonds 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 laws, including particularly such provisions as have hereinabove been specifically authorized to be included in any resolution or resolutions of the authority authorizing revenue bonds thereof. Any bank or trust company incorporated under the laws of the state which may act as depository of the proceeds of bonds or of revenues or other moneys may furnish such indemnifying bonds or pledges such securities as may be required by the authority. Any such trust agreement may set forth the rights and remedies of the bondholders and of the trustee or trustees and may restrict the individual right of action by bondholders. In addition to the foregoing, any such trust agreement or resolution may contain such other provisions as the authority may deem reasonable and proper for the security of the bondholders. All expenses incurred in carrying out the provisions of such trust agreement or resolution may be treated as a part of the cost of the operation of a project.