B&O EM-1 and Big Six By Angela Cotey | March 1, 2022 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates In the Potomac River narrows west of Cumberland, Md., on Baltimore & Ohio’s main line to Pittsburgh, EM-1 2-8-8-4 7613 and 2-10-2 6222 doublehead on a westbound freight in May 1952. Edward Theisinger photo