Mass. Gen. Laws ch. 161 § 129
For the purpose of avoiding or abolishing a crossing of a railroad by the tracks of a street railway company at grade, the company may purchase or take by eminent domain under chapter seventy-nine land necessary therefor, not exceeding fifty feet in width, outside the limits of a public way; but no land shall be so taken which cannot lawfully be taken for the laying out of a railroad, nor shall it be so taken until a plan on an appropriate scale, showing by metes and bounds the land, and the names of the owners thereof, has, after notice to such owners, and after such public notice and hearing as is required by section seven, been approved in writing by the board of aldermen of the city or the selectmen of the town where such land is situated; nor shall the land of a railroad corporation or of another street railway company be so taken without its consent, except with the approval of the department after notice and a hearing.
Mass. Gen. Laws ch. 161, § 129