Section 16. Any holder of bonds issued under the provisions of this chapter or of any of the coupons appertaining thereto, and the trustee, except to the extent the rights herein given may be restricted by the trust agreement securing the same, may, either at law or in equity, by suit, action, mandamus or other proceeding, protect and enforce any and all rights under the laws of the commonwealth or granted hereunder or under the trust agreement, and may enforce and compel the performance of all duties required by this chapter or by the trust agreement to be performed by the issuer or by any officer or agency thereof.