Bulk freight not sensitive to weather has always been important transport freight for the railroad. A total of 16,200 units of the class Otmm 70/Ed 90/Fc 090 were therefore built. This makes them hopper cars built in the largest numbers for the German Federal Railroad. With a wheelbase of 6 meters / 19 feet 6 inches and a length over the buffers of 9.64 meters / 31 feet 4 inches, these cars offer a load volume of 40.0 cubic meters / 1,412.59 cubic feet. The weight of the cars empty is 11.6 metric tons. During unloading, the load slides to the openings in the middle of the car. These are closed by gates, which allows a measured unloading. The load is moved by slide extensions from the exit openings to the side of the car.