The EMD F3 is a B-B freight- and passenger-hauling carbody diesel locomotive produced between July 1945 and February 1949 by General Motors’ Electro-Motive Division. Final assembly was at GM-EMD's La Grange, Illinois plant. A total of 1,111 cab-equipped lead A units and 696 cabless booster B units were built. The F3 was the third model in GM-EMD's highly successful F-unit series of cab unit diesel locomotives, and it was the second most produced of the series. The F3 essentially differed from the EMD F2 in that it used the “new” D12 generator to produce more power and from the later EMD F7 in electrical equipment. Some late-model F3's had the same D27 traction motors, along with the heavier-duty electrical cables, used in the F7, and were referred to as model F5 by EMD's Engineering Department. Engine and powertrain The F3 used a 16-cylinder 567B series diesel engine developing at 800 rpm. The 567 was designed specifically for railroad locomotives, a mechanically scavenged, or "blown" 2 stroke 45 degree V type with displacement per cylinder, for a total of . A D.C. generator powered four traction motors, two on each Blomberg B truck. EMD has built all of its major components since 1939. Identification As built, the only way to distinguish between the F2 and F3 was the nose number panels on the A units, which were small on the F2 and large on the F3 and subsequent locomotives. However, these could and were often altered by the railroad. Few F2s were built, however. Early versions of the F3 had the "chicken wire" grilles along the top edge of the carbody. Later production featured a distinctive fabricated stainless steel grille. All F-units introduced after the FT have twin exhaust stacks and four electrically powered radiator fans arranged close together atop their roofs, unlike the FT's four stacks and separated belt driven pairs of fans. F3 phases The identification of locomotive "phases" is a creation of railfans. EMD used no such identification, and instead only kept track of the marketing name (e.g. F2, F3, F7, etc.) and individual locomotives' build (serial) numbers. During the production cycle of a particular model, as design and production techniques improved, all builders would invariably make minor changes. To better keep track of noticeable, and not so noticeable differences in appearance that a locomotive model would acquire during the course of its production run, locomotive historians began