V-2 rocket offensive began on 8 September 1944, when "Lehr- und Versuchsbatterie No. 444" () launched a single rocket guided by a radio beam directed at Paris. Wreckage of combat V-2s occasionally contained the transponder for velocity and fuel cutoff. The painting of the operational V-2s was mostly a ragged-edged pattern with several variations, but at the end of the war a plain olive green rocket also appeared. During tests, the rocket was painted in a characteristic black-and-white chessboard pattern, which aided in determining if the rocket was spinning around its longitudinal axis. The original German designation of the rocket was "V2",
2-8-8-4 of the diesel locomotives since they were showing improved performance over steam locomotives. But the War Production Board regulated the production of steam and diesel locomotives until the war emergency was over. So along with producing 40 new class T-3 4-8-2 type locomotives built in-house at their Mt. Clare shops in Baltimore, Maryland, the B&O took delivery of 30 class EM-1 Yellowstones in 1944 and 1945, the largest number and the smallest of this type built by Baldwin as well as the most modern. The EM-1 produced of tractive effort on drivers with steam pressure and four cylinders. The tender