Mass. Gen. Laws ch. 160 § 115
A railroad corporation, after having finished the construction of its railroad and put it in operation, may build a branch or extension thereof in accordance with this chapter, if an amount of additional capital stock, applicable solely to the construction of such branch or extension, has been subscribed, and a certificate of the department that public necessity and convenience require the construction of the branch or extension has been obtained, and a certificate of the clerk of the department has been filed according to section seventy-six; and it may build such branch or extension without additional capital stock, if its indebtedness is not thereby increased; but this section shall not invalidate a lease or contract between railroad corporations made pursuant to law. Upon the filing of such certificate, fifty dollars shall be paid to the state secretary. If the construction of such branch or extension is not begun, and ten per cent of the additional capital stock is not expended thereon within two years after the date of the certificate required by section seventy-six and the branch or extension completed and put in operation within four years after said date, the power of the railroad corporation to construct the same shall cease.
Mass. Gen. Laws ch. 160, § 115