At age 14, I was very new to the hobby, and inexperienced in identifying locomotives. For the most part, a had to rely on photo captions from Trains magazine to try and figure out what I'd shot.
Spotting the same "design" features -grills, filters, and portholes - I identified the machine as an F7; which I later deduced was an F9, spotting the extra filter in front of the first porthole.
And having stood in front of the builders plate, dutifully copied the date built and serial number off that iconic piece of metal; "10/27/48, #6652." Indeed, I wrote a Blog article about this unit back in 2009. Turns out it was an F9, not an F7 as I incorrectly cataloged it in 1959.
And the booster unit was totally messed up. I could not find a unit number nor a builders plate.
The gentleman who requested enlarged scans promptly responded to me, and suggested that the photo I had taken, behind Sears, at Stacy Street Yard in Seattle, was neither an F9 nor an F7, but an F3!
Perplexed, I decided to challenge what my eyes were telling me. Let's review: I took the photo of NP 6500C at Stacy Street in July 1958. In my description I have her listed as built 10/27/48, SN 6652. Those are the facts, and cannot be disputed.
But when I looked up that serial number that I wrote in my pocket notebook — 6652 — in the EMD Unofficial Web site, she's listed as an F3. Yet when I enter NP 6500C in the EMD site, it comes up with a different serial number: 8731:1, listed as F7, rebuilt to F9 sn 8731:2!
According to Jerry Pinkepank's "Diesel Spotters Guide," [2nd edition]
• FT were in production from 11/39 through 11/45
• F2 were in production from 7/46 through 11/46
• F3 were in production from 7/45 through 2/49
• F7 were in production from 2/49 through 12/53
• F9 were in production 1/54 through 1955
Note, General Motors did not produce F4, F5, nor F6. At least officially. But then when it comes to the F5 — well, I'm getting ahead of my self, as you will soon learn.
Since MY photo taken in 1958, shows an F3 serial number, why does she look like an F7? Err ? F9?
I reached out to an email correspondent knowledgeable in all things Northern Pacific, who in turn passed my enigma along to Bill Kuebler.
Mr. Kuebler, a commercial airline pilot, possesses a remarkable Northern Pacific database, and has authored two definitive books: "Northern Pacific: Color Pictorial Volume 3" and "The Vista-Dome North Coast Limited: The Story of the Northern Pacific Railway's Famous Domeliner."
This is Bill's response to my initial inquiry, presented here with his permission, on the curious life of NP 6500C, who despite "looking like a duck and talking like a duck, was not a duck."
"Robert. Our mutual friend, Dave Sprau, has made me aware of a question you have regarding some confusion about NP diesel unit no. 6500C, which you photographed in 1958. You're not the only one to experience this sort of thing. The history of that unit is unique and tends to cause confusion.
"First, some background. Much of what you're about to read is about certain aspects of NP diesel history that, in themselves, are cause for confusion about NP's passenger F-unit fleet, even apart from the number "6500C".
"6500A,B,C - 6506 A,B,C (first) were delivered new as F3 A-B-B sets in 1947. These were what EMD called "Phase I" F3 units. EMD produced a total of four phases of F3 models, but NP purchased only Phase I F3 units in 1947, and some Phase IV F3A (cab) units in 1948 for both freight and passenger service.
"Over the next couple of years after 1947, NP modified its passenger F3A units to Phase II F3A configuration, and then to Phase III F3A configuration. The original Phase I passenger F3As were never modified to Phase IV configuration, only up to Phase III. NP's Phase I F3A freight units, however, remained in their original Phase I configuration throughout their service lives.
"These changes to the original F3A passenger units (6500A - 6506A) show up in photos and cause some confusion among those unfamiliar with these details. In fall 1948, locomotives 6503-6506 (three-unit sets) were re-configured to F3A-F3B-F5A sets, i.e. cab-booster-cab sets. In each case, the rear booster unit was moved forward to the middle position and re-numbered 6503B - 6506B, respectively, and the middle booster was taken out of the set entirely and converted to freight service and given freight numbers in the 6000 series.
"The new F5As were numbered 6503C - 6506C (2nd). Thus, the third unit in each set was newly purchased from EMD as what the builder designated a "Phase IV" F3A unit. The NP, however, decided to designate that unit an "F5A." So, "F5" or "F5A" (there were no F5Bs) was simply NP-talk for a "Phase IV F3A."
"EMD did not use the "F5" designation. I don't know the reason for this; perhaps a reader may know.
"The F5As look from the ground much like F7As, which is cause for some to think they are F7s. They are not F7s. Basically, an "F5" was an F3 mechanically but with F7-level electrical components, including traction motors. The F5As did not have a roof-level fan for the dynamic brake, as did F7s, so that's a spotting feature that one can use to identify an F5A. So technically, it would be correct to call these new cab units "F3s," and it would be wrong to call them F7s, but it would be better to call them "Phase IV F3s, which NP called F5s." That's wordier, but is more accurate and avoids confusion.
"Then, in April 1949, NP did something similar to locomotive sets 6501 and 6502. In this case, the NP took the REAR booster out of each set, renumbered them 6507B and 6508B respectively, and "trio-ed" them with new F7As on each end, nos. 6507A/C and 6508A/C, respectively, forming two F7A-F3B-F7A sets.
"Units 6501B and 6502B remained as they were, where they were---the middle unit in the respective set. At that time two new F7A units were purchased and numbered 6501C and 6502C. These joined the existing 6501 and 6502 sets, forming two F3A-F3B-F7A sets. So 6501C and 6502C were definitely F7s, not F3s (in any phase).
"Then in September 1949, NP finally did the same thing with the one remaining passenger F-unit set in its original unit-configuration, locomotive 6500, but this time they once again moved the rear booster up to the middle position, re-numbered it 6500B, and then took the MIDDLE booster out of the set (as with 6503-6506), renumbered it 6509B, and "trio-ed" it with 6509A/C, two new F7A units, again forming an F7A-F3B-F7A set.
"A new F7A unit, 6500C, then joined the existing 6500 set, forming an F3A-F3B-F7A set, just like the 6501 and 6502 sets. So the second 6500C was in fact a new F7A. It was never an F3 of any kind. Locomotive sets 6510A,B,C - 6513A,B,C were newly purchased F7A-F7B-F7A sets.
"They were the only "pure" three-unit F7s passenger sets on the NP. The NP began to "break up" the F-unit sets in the mid-1950s, and by 1960, all the F-units in the transcon fleets (freight and passenger) were treated essentially as individual units from which they would create any F-unit lashup desired for a particular job.
"That's why the cab units were given letter suffixes in their number boxes and on their rear flanks starting in late 1954/early 1955, and why the booster units were finally given large 12-inch numbers on their rear flanks in spring 1961.
"Now, if you've tracked all that...we can move on to 6500C. The unit in question was actually 6500C (2nd). Remember, the first 6500C was a booster that was moved forward in the set to become 6500B in September 1949. So...6500C (2nd) was an F7A. It was not ANY phase of F3. It was a pure F7A from the git go and purchased new. It was an in-service F7A until August 15, 1955, that is.
"On that date, it was wrecked in a terrible head-on collision at Cheney, WA, killing the locomotive engineer, Sam Moats (69 years old and near retirement). The train was running as No. 5 and collided with Class Z-6 no. 5119, a 4-6-6-4 type steam locomotive, at the east switch in Cheney. Powering the passenger train was 6500C,B,A.
"The lead unit, 6500C, was broken into two large pieces, both halves badly smashed. The unit was basically destroyed. What was left of the 6500C was sent to South Tacoma shops, where it was supposedly "rebuilt" to an F9A. In reality, most of it was scrapped. They may have used a few parts from it, but not many. I think in truth the NP pulled a fast one on the government (if that's possible) and somehow managed to get a more-or-less new F9A without having to pay taxes on a new purchase, but that's just conjecture.
"Shop superintendent Elmer Smoak was in charge of that shop work on 6500C, and he told me personally that "in no way" was the wrecked unit "rebuilt" to an F9. Almost all of it was scrapped. How the "rebuilt" F9A came to be remains a bit of a mystery. That's all I can tell you on that score. Anyway, a few months after the wreck, number "6500C" was thereafter carried by a pure F9A passenger unit.
"This is the unit that appears in the photograph at the bottom of the email Dave forwarded to me from you, and it would be the unit you photographed in 1958. So from whatever date that "rebuilt" unit emerged from South Tacoma (spring 1956, I believe), it was no. 6500C and it was an F9A that looked EXACTLY like all the other NP passenger F9A units. Everything about it, inside and out, was an F9A. It was not a "mix-and-match" deal. If it had any parts from the wrecked 6500C, there couldn't have been very many.
"So if you photographed no. 6500C in 1958, then you photographed an F9A that was shown in company records as having been "rebuilt" (but not really) from a wrecked F7A. The designator "F3" had absolutely no place in the story--except that the FIRST "6500C" was, indeed, an F3B---a booster unit. But, we're talking here about the 2nd 6500C, which had nothing to do with the first other than that it carried the same four digits.
"Finally, in March 1965, NP decided it was time to end the charade and give that "rebuilt-new" F9A a number in accordance with the passenger F9 fleet's numbers. The 6500C was then re-numbered 6703C, which it carried until after the BN merger.
"If the serial number you observed is in conflict with this history--and it appears that it was--then the NP must have had a wrong serial number displayed on a passenger unit, which only deepens the suspicion I have about how and why company records would show this unit as an "F7 rebuilt to F9" status. One really wonders just what was going on.
"To answer question about that long hose on the front end of 6500C. It connected the rear locomotive unit on passenger trains (specifically Nos. 25/26 and 1/2) to the water-baggage car, which was the first car behind the engine. As you may know, the water-baggage car had large water tanks in the A-end. The water was for the engine's steam generators, for train heating, hot water systems, etc.
"A floor-level cross-over pipe kept lateral balance in the water-baggage car, and a floor-level pump controlled by a float valve in the B-unit's large tank pumped the water from that car forward to the booster unit(s). From there it flowed into the B-unit's large water tank and also to the cab units' "hip tanks" ---smaller (480-gallons total per unit) water tanks mounted along both side walls in the engine rooms of the cab units.
"To keep water in that long hose from freezing in super-cold winter weather, it was spiral-wrapped with a steam line. The metal coupling between hose and water-baggage car, however, was not sufficiently covered by this steam hose, so in very cold temps the coupling could freeze and block water flow. This happened on several occasions, and on at least one of them--in February 1969 with No. 26's train between Dilworth and Staples--the train rolled into Staples about to freeze up, with a panicking road foreman named Glenn Hove in the cab.
"He told me that had Staples been another five miles east of where it was, they would have frozen up the train for sure. It was about 30-below zero that night.
"If you can't see the roof of an F5A and aren't familiar with NP's numbers assigned to the various models, and you're not familiar with the headlight arrangements on NP's F-unit fleet, then yes, it's pretty much impossible to know that it's an F5A versus an F7A without crawling inside the unit and taking a close look at various components.
"General Motors, Electro Motive Division (EMD) didn't really fail to acknowledge the F5's existence. Rather, they simply called it a Phase IV F3. Perhaps your question is really getting at why EMD skipped use of the F5 designator and went straight to the F7 after the F3 series. For that matter, since there WAS an F2 from EMD, why did EMD also skip F4 and F6? Answer: Nobody seems to know. It will remain a mystery forever unless someone who really was there and can speak for EMD steps up to the plate.
"At this stage of things that seems unlikely to happen. And, perhaps your question is getting at why the NP went with "F5" in its designation rather than "F3" as EMD would have done. That much I can answer. The road believed that there were enough differences in the unit from both the F3 (previous phases) and later F7 models that it warranted its own designation. There's a lot of truth to that idea. The F5s did have more modern, higher capacity traction motors, for example, than the F3s had, and other important features "under the hood," so to speak, that made them a substantial improvement over previous phases of F3--but yet not quite an F7 either. In fact, because of some of these features the F5s performance was better than the earlier phases of F3s. So that was the logic behind it all.
"There was a fairly steep "learning curve" at EMD during the development and production of early F-unit models. This is why there were four phases of F3s. Much improvement was happening during this steep learning curve. Most of the improvement was happening "under the hood" and so external spotting features didn't always change much. That B-unit is indeed no. 6550. Technically, it is 6550B, but the "B" suffix was left off the number as applied to that unit's flank. The number at the "A-end" (i.e., front end) of the unit is a small, 2-inch number.
"In spring 1961, large 12-inch numbers would be applied to the "B-end" (rear end) of all NP B-units in both freight and passenger service. But the 6550 was the only B-unit never to receive the letter suffix on the number as displayed on the unit itself, although on NP's official roster, it WAS shown as "6550B."
"Since there was no three-unit set numbered 6550, the NP figured this lone unit never really needed a letter suffix. This gets back to the reason the NP adopted the letter suffix concept in the first place: to keep unions from falsely claiming that each unit was a distinct "engine" and required its own crew. At first, all FTs and F3s were simply numbered in sets, as in 6500, 6501, etc. With each unit carrying the same road number (e.g., "6500"), the company figured that a case for each unit requiring its own crew would be much more difficult to make. And, technically, the NP was correct. A three-unit diesel locomotive is just that--a single locomotive (one engine) comprised of three units.
"But then, in the early 1950s, the NP started thinking about splitting up these sets so as to form different combinations of locomotives with tonnage-appropriate horsepower in the lash-up. This meant the possibility of two different trains having a lead unit numbered "6500" (one being "A" and the other being "C").
"This, of course, would pose a serious problem with rules, train orders, safety, etc. So the concept of a letter suffix was born. The small 2-inch numbers ALWAYS had letter suffixes, but those were just to keep shop personnel straight on which unit was which, etc. Letter suffixes were added to the number boxes on the noses, and to the 12-inch numbers on the flanks of the cab units, beginning in late 1954. This took care of the confusion problem with two cab units from the same original set possibly encountering each other out of the road.
"Anyway, that one in your photo is an F7B, but it is unique in its appearance, probably because it was built late in the F7 program, in 1952. The other F7s were all built in 1949. The 6550 has a middle porthole. Other NP passenger B-units in the 6500 series (not the 6700s, though) had their middle portholes replaced with a single louver in about 1952--and there were three F3Bs that were exceptions to this. They all retained three portholes.
"Long story there, too. Anyway, all B-units originally had three portholes, like we see on 6550. Also, the grille on 6550 is a bit more modern than the grilles on the earlier F7s. I'd have to double check some photos to be sure of that point, but I think that was the case. If we could see the roof, I believe we might also see a more modern, 48-inch dynamic brake fan--but don't quote me on that. I'd have to double check photos to be sure. If not, then it had a standard 36-inch fan over the dynamic brake.
"My suspicion was correct. That is the 6550 for sure. I was able to pick out the second and fourth digits with absolute certainty. They are a "5" and a "0" respectively. That means it was definitely NOT an F9 unit (or else the second digit would be a "7"). The grille shows that it was definitely NOT an F3 unit. So it has to be an F7. The only other F7 with the last digit of "0" was 6510B, but that one DID have a letter suffix applied to the 2-inch number from the git go. There is no letter suffix in the 2-inch number in your photo, so by process of elimination, it has to be unit no. 6550. There is no doubt.
"Anyway, now you know the rest of the story, as Paul Harvey would say. Let me know if you have any further questions. Bill Kuebler."
I am in debt to Bill Kuebler and Dave Sprau for helping me solve a truly remarkable enigma surrounding "a duck that wasn't a duck."
("Click Here" for another highly detailed discussion on the F3, with further analysis of unofficial phases, by Ryan Kunkle.)
There is an entire generation of Septuagenarians who mucked about taking photos of trains, back in the time when there were more than 120 Class 1 railroads in the US, Canada and Mexico.
So it is imperative that my generation passes along — shares stories, photos, and antidotes — of the Real Railroading Generation.
But it must be done responsibly, with attention to details, like this with the NP 6500C, to prevent contaminating railroad history.
I have plenty more to share.