EMD used two sizes of circular fans on their dynamic brake systems on their F7 and F9 units. The earlier FT's, F2s and F3s used a different system. No exposed exterior circular fan for the dynamic brake on these units until the very last F3s, which did use a F7 style circular fan. EMD's two sizes of dynamic brake fans were 36" diameter and, later, 48"diameter. Generally, all F7s equipped with dynamic brakes used the 36" fan until late in the F7 production life. Later F7s, and all F9s, equipped with dynamic brakes used the 48"diameter fan. The Frisco did not have dynamic brakes on its F7s. Each of the Frisco F9Bs, SLSF 5140-SLSF 5152, came with dynamic brakes and used the 48" fan. My question is what about the two rebuilt F3As, SLSF 5005 and SLSF 5007? These two original 1500 HP, non-dynamic brake F3As were rebuilt into F9A specifications in 1954, raising them to 1750HP. During the rebuild dynamic brake systems were added to each. What size dynamic brake fans did SLSF 5005 and SLSF 5007 use - 36" or 48"? I have two Stewart F9As, both undecorated, that are nearing their ultimate date with the Frisco black and yellow paint shop. They have the 48" dynamic brake fan. Is that correct for F9A SLSF 5005 and SLSF 5007? Ken
here are a couple of pictures of one of the locomotives in question. Notice that the dynamic brake fan looks much larger than the cooling fans, leading me to believe that they did upgrade to a 48" fan.
Sorry to bust in on your thread, but can you tell me if the F3s had the smaller-taller fans, or the later type used on F7s, F9s, GP7s and such?
Sure, no problem! The early phases of the EMD F3s did not have an exposed circular fan for the dynamic brake system, but instead had the dynamic brake resistors exhaust their heat upward through two rectangular grills in the roof. They were located at the same spot as the later dynamic brake fans. The F2 used the same system. The earlier FT had the dynamic brake grids mounted higher, and had a boxy looking housing for the dynamic brake exhaust. The final phase of the F3, Phase IV, used the 36" diameter dynamic brake fan that was later used on the F7, Phase I. The F7, Phase II, used the 48" fan, as did all the F9s. FP7As used 36" fans, FP9As used 48" fans. As always, there were exceptions and retrofits to keep us all confused. If you can ever locate a copy of the Extra 2200 South, January 1970 issue, it has an article "All About Fs" which is like candy for F-lovers! It discusses all these details. They were the ones who started all these "phase" designations for diesel locomotives. The builders did not use these designations. They are a railfan invention. For Frisco F-units, this discussion is moot. No early Frisco F-units had dynamic brakes, until the F9Bs and the two F9As rebuilt from F3As discussed above. All these later units used the 48" fan. Ken
Close, Ken, but no cigar. Hey, If the "big reds" were still around, Frisco could have named one "Cigar". In my question I was referring to the cooling fans, not dynamic brake fans.
Sorry! I just came back from the barber shop and while sitting there talking about NCAA basketball, it struck me that you were probably asking about radiator fans. You asked about their height. Funny how the mind works! Early F3's, and all F2's, came with the high 36" radiator fan shrouds. They also had three portholes on the A-units. The Phase II F3As still had high fans, but went to two portholes on the side covered by a big wire mesh grill. F3A Phase III units went to the low 36" fan, but kept the wire mesh over the two portholes. Late F3A Phase III units kept the low 36" fan, dropped the big wire mesh grill in favor of vented louvers, keeping the wire mesh over only the top row of cab-side openings. Phase IV F3As looked just like the F7A Phase I, with low fans, louvered openings, but with a horizontal Far air grill over the top openings. The F9A added a fifth louver just in front of the front porthole, and switched to a vertical Far air grill over the top row. FP7s were like the F7s, FP9s like the F9s. Whew! Got all that? Frisco's F3As were easy to figure out. The first two, SLSF 5000 and SLSF 5001, were "early" Phase III F3s, with the big mesh grill and low fans. All the remaining F3s, SLSF 5002-5017, were "late" Phase III F3s, with two port holes, mesh grill over the top openings, low fans. All of the Frisco F3Bs had three portholes, mesh over the top side openings, no louvers and low fans. I am worn out! Just kidding. Ken
All I can say is, Which came first - the chicken or the egg? I bet you are worn out after that. Thanks, I really appreciate it. That is some good information for me to file for reference later. Darn it! - I wanted to model the taller fans on an "O" scale F-3 I am rebuilding. I really like the looks of them for some reason, plus I liked the 3 portholes better than the 2. Oh well, I will just go ahead and make it into a KCS and do another for the Frisco. I have an Atlas BN F9A that I will kitbash towards the Frisco. Here I am sitting, waiting for a response, and you are out getting your ears lowered. LOL. Appreciate it much. Did you catch the photograph I just added on the tank car?
