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Electro Motive Corporation (EMC), later Electro Motive Division (EMD) made the popular "E" units and "F" units. Some railroads bought E and some bought F. What is the difference between them? My question is not really a technical question, but more of a question of what were the good and bad points of each. I am really wondering why some railroads would buy E units and others would buy F units.
I used to think that F units replaced E units, but I have just read where E units continued to be made while F units were also being made.
Thank you
------------------ Elias Valley Railroad (N-scale) www.geocities.com/evrr
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I just have some of the pieces and perhaps they will fill in some of the gaps. the first EMD-GM diesel was the FT, made between 39-45.F standing for freight, T standing for 2700 horsepower,A&B unit combined. Then you have F2,3,7&9,FP7 that were manufactured between late 40's and early 50's and were best suited for over the-road freight transport. Your earliest E units were, E2/3/4/6. I don't know if there was a 5. The E stood for 1800 horsepower, the units carried two-900 hordepower 12-cylinder engines. After wartime restrictions were removed, railroads upgraded and started dieselizing their passenger service starting in 1945, hence the E7-2000 horsepower. The E7 was superseded in 1949 by the E8-2,250 horsepower and was replaced in 1954 by the E9-2,400 horsepower. Then you have the FP45-3600 horsepower made between 1967/68 originally for passenger service but reassigned to freight because of passenger-train abandonment. I HAVE SAID TO-TWO-2-TOO MUCH.
Posts: 213 | From: Grand Rapids Mi USA | Registered: Apr 2001
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The E units were almost exclusively built for passenger service and rode on A-1-A trucks. While most F units were built for freight service and all rode on B-B trucks, some were equipped with steam generators and were used in passenger service. The FP7 steam-gnerator equipped engine was four feet longer than its F7 freight only cousin. I believe the Sante Fe also had some F3B units equipped with steam generators, but these engines were not designated as FP3Bs.
The E units were geared for passnger speeds which usually were above the F unit freights.
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The E-units are a six axle locomotive, while the F-units were four axle units. The E-8/9 shared nose and cab details with the F units, but not many other details were similar. They were both produced at the same time. Original E's really can't be mistaken for anything else because of the sharp rake of the nose. Starting with the E-6, the nose became more vertical, with the E-7 having nearly the same angle as E-8/9 and F's.
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Thank you for your answers. I already knew about the two versus three axles. What I am really wondering, is why is that important? Why would some railroads want engines with three axles and other railroads wants engines with two axles.
------------------ Elias Valley Railroad (N-scale) www.geocities.com/evrr
posted
Constantin, first, all "E" (for Express) units had three axle trucks with traction motors on only two of those axles, or an A-1-A truck. In addition, all E's had not one but TWO prime movers and two generators. With their gearing, they were built strictly for speed to pull passenger trains. "F" units had two axle trucks, with traction motors on both axles, and a single prime mover and generator and were mainly geared for pulling power, not speed, at least initially. While it was fairly easy to adapt F units as passenger engines, the few E's regeared for freight service were poor performers.
Posts: 23 | From: Florida | Registered: Sep 2001
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