The commission shall give the railroad corporation thirty days' written notice of the proposed work, accompanied by a plan thereof; and if the commission is unable to agree with the railroad corporation across whose land or location it desires to lay out, extend and construct a boulevard, it may have its right to cross and the manner of crossing determined by the department of telecommunications and energy; provided, that no crossing of such boulevard shall be at a level with the railroad tracks and that no such boulevard shall be laid out, extended and constructed across a railroad in such manner as to injure or obstruct the railroad.
Mass. Gen. Laws ch. 92, § 50