Air repeater By Brian Schmidt | February 22, 2024 Email Newsletter Get the newest photos, videos, stories, and more from Trains.com brands. Sign-up for email today! Get Updates Burlington Northern car BNH 4, seen at Grand Forks, N.D., in 1996, was built in 1955 as Great Northern boxcar no. 5158. It was converted to an air repeater car in 1971. Note the manway door and stirrup step in the side and the twin beacons on the roof. Cody Grivno photo