Mass. Gen. Laws ch. 159 § 1
Every common carrier of merchandise or other property shall receive, transport and forward all property offered for such purposes by other such carriers as promptly, faithfully and impartially, at as low rates of charge, and in a manner and on terms and conditions as favorable to the carrier offering such property, as he on the same day and at the same place receives, forwards and transports, in the ordinary course of business, property of a like description offered by persons other than such carriers. Such carrier shall not discriminate against any particular person or subject him to any undue or unreasonable prejudice or disadvantage. The supreme judicial or superior court shall have jurisdiction in equity to enforce this section.
Mass. Gen. Laws ch. 159, § 1