Section 13A. A corporation subject to this chapter may, by vote of the holders of a majority of its shares outstanding and entitled to vote thereon at a meeting called therefor, or by vote of its directors under authority of a vote of the holders of a majority of its shares outstanding and entitled to vote thereon at a meeting called therefor, and subject to the limitations and restrictions of section fourteen but without regard to the limitations and restrictions of section fifteen, for the purpose of securing other bonds issued by it, issue and pledge bonds secured by prior liens upon all or part of the property mortgaged to secure such other bonds, in a principal amount not exceeding the principal amount of such other bonds, such issue and pledge to be to such extent and upon such terms as the department may approve; and such prior lien bonds shall not be counted in applying any limitations of law upon the amount of its outstanding bonds or for purposes of section sixteen.