EMD F-unit

EMD F-units are a line of diesel-electric locomotives produced between November 1939 and November 1960 by General Motors Electro-Motive Division and General Motors-Diesel Division with 7,642 units produced. Final assembly for all F-units was at the GM-EMD plant at La Grange, Illinois, and the GMDD plant in London, Ontario. They were sold to railroads throughout the United States, Canada and Mexico, and a few were exported to Saudi Arabia. The term F-unit refers to the model numbers given to each successive type (i.e. F3, F7, etc.), all of which began with the letter F. The F originally meant "fourteen", as in 1,400 horsepower (1,000 kW), not "freight". Longer EMD E-units for passenger service had twin 900-horsepower (670 kW) diesel engines (called "prime movers" in that type of application). The E meant "eighteen" as in 1,800 horsepower (1,300 kW). Similarly, for early model EMD switchers, S meant "six hundred" and N meant "nine hundred horsepower" (450 and 670 kW respectively). F-units were originally designed for freight service, although many without steam generators (for steam-heating passenger cars) pulled short-distance, mainly daytime, passenger trains. Some carriers even equipped small numbers of their Fs with steam generators for long-haul passenger service. On the other hand, Santa Fe maintained a large fleet of fully equipped, high-speed F3s and F7s in "warbonnet" paint schemes built exclusively for top-tier passenger trains, such as the Chief, Super Chief, and El Capitan. Almost all F-units were B-B locomotives, meaning that they ran on two Blomberg B two-axle trucks with all axles powered. The prime mover in F-units was a sixteen-cylinder EMD 567 series mechanically aspirated two-stroke diesel engine, progressing from model 16-567 through 16-567D. Structurally, the locomotive was a carbody unit, with the body as the main load-bearing structure, designed like a bridge truss and covered with cosmetic panels....