Bankruptcy Judge Louis Kornreich formally on Thursday approved the Montreal, Maine and Atlantic Railway’s sale to Railroad Acquisition Holdings LLC, an affiliate of New York-based Fortress Investment Group. The decision came simultaneously with a Canadian bankruptcy court proceeding. The $15.85 million deal is expected to be closed by mid-March, said Robert Keach, the railroad company’s trustee in its bankruptcy proceedings. Railroad Acquisition Holdings began the bidding with a stalking-horse bid of $14.5 million. MM&A filed for chapter 11 bankruptcy in U.S. Bankruptcy Court in Bangor on Aug. 7, 2013, a month after one of its trains rolled driverless down a hill before derailing in the middle of the town of Lac-Megantic, Quebec, causing an explosion that killed 47 people on July 6, 2013.