Mass. Gen. Laws ch. 160 § 45
Any preferred stock issued under authority of section forty-three shall have the same voting power as the common stock, except that, in any case, there may be such limitations of the voting power of the preferred stock as the department approves and finds to be consistent with the adequate protection of the public interest. The aggregate amount at par of preferred stock of all classes issued by a railroad corporation shall at no time exceed twice the amount at par value of its outstanding common stock, and no class of preferred stock shall be created which is not, in a manner approved by the department, made subordinate in respect to dividends or to participation in the proceeds of liquidation to the preferences of every previously created class of preferred stock.
Mass. Gen. Laws ch. 160, § 45