Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 160, § 5

If a railroad which has been laid out and constructed by one corporation is lawfully maintained and operated by another corporation, the latter corporation shall be subject to the provisions of this chapter and chapter one hundred and fifty-nine respecting or arising from the maintenance and operation of such railroad, as if such railroad had been laid out and constructed by it. If a railroad is lawfully maintained and operated by trustees, they shall in like manner be subject to the provisions of law respecting or arising from the maintenance and operation of such railroad which apply to the corporation for whose stockholders or creditors they are trustees.