Mass. Gen. Laws ch. 161, § 48: Use of railroad tracks

Section 48. A company, with the consent of a railroad corporation owning tracks, may, to such extent and subject to such terms and regulations as the department may approve or prescribe, operate cars upon and over such tracks of said railroad corporation as are equipped for operation by the electric system of motive power, and may connect its own tracks with the tracks of such railroad in such manner as may be agreed upon by the two companies and approved by the department.