Question for SF (warbonnet) freaks

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E7
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Question for SF (warbonnet) freaks

Postby E7 » Fri Dec 03, 2021 9:29 pm

I recently saw an SF model listed as an E8 with E7 style 45 degree number boards. It had all the E8 junk on the roof!

An error by the model builder, or was EMD just using up of old parts?

Chris Webster
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Re: Question for SF (warbonnet) freaks

Postby Chris Webster » Fri Dec 03, 2021 10:07 pm

E7 wrote: or was EMD just using up of old parts?
Perhaps - the ATSF's small fleet of E8s were all rebuilt from very early E units that were built with Winton engines. My recollection is that the ATSF stopped buying E-units after they got their first passenger F-units -- I presume they realized that E's were not well suited for Raton Pass.

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Re: Question for SF (warbonnet) freaks

Postby ScaleCraft » Sat Dec 04, 2021 2:14 am

I've got a story written in Railfan magazine, I think, guy who ran E-units on the ATSF...and they hated them on the Rat. The 4 traction motors with idler centers didn't pull worth a crap.
Dave....collector, restorer, and operator of the finest doorstops

E7
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Re: Question for SF (warbonnet) freaks

Postby E7 » Sat Dec 04, 2021 3:29 am

Dave, I'm far from an expert on this stuff, but I think the issue may have been the gearing. An E8 had way more horsepower then an F unit....2250 as I recall vs. 1500. Doesn't answer the original question. I still think they were using leftover parts from earlier runs. Not buying into the story of upgrading old E's because of timing and the bodies were too different. I've yet to see a real E8 with 45 degree boards, maybe the model builder Lovelaced it! :shock:

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sarge
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Re: Question for SF (warbonnet) freaks

Postby sarge » Sat Dec 04, 2021 6:52 am

Rich, prototype photos show ATSF E8s with F-unit style boards. That explains the model; its correct.

I suspect they did them specifically so the location and size of the numbers on the nose was in common with the fleet of contemporary Fs and big enough so operators could easily read the numbers on the fly for their trainsheets and train-order reporting requirements. Earlier cabs with the small boxes on the noses, up through the PAs, had those big illuminated number boxes on the flanks for the same requirement.

There is a who-dunnit question, though. I found an early photo of 83 with standard E8 boards, then several later shots of the same unit with F-style boards. One could guess it was Santa Fe that changed them rather than EMD that built them that way.

BTW, although theirs were apparently “rebuilds” from E1s turned back to EMD, done in 1952 or so, that really shouldn’t have any bearing on the E8 carbody configuration.
No-one ever forgets where they buried the hatchet.

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sarge
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Re: Question for SF (warbonnet) freaks

Postby sarge » Sat Dec 04, 2021 7:39 am

If one really cares about this technical bit, read on, but I don’t recommend it. GRIN!

Es versus Fs or “Why did ATSF use F-units in passenger service?”. In short, it isn’t horsepower that makes the difference, but tractive effort. The following is really simplistic on the one hand, but done so for clarity on the other.

TE defines how much you can move against how much resistance. The latter is supplied by all sorts of things like gradient, lateral curvature, rolling resistance, even how many up- and down-grades are in the length of a train at a given moment. Against that, you have (very basic) how many driven axles available to you and how much axle-loading is on those axles. In short, if you were to assemble a 4500hp loco of Fs, you’d have 12 powered axles on the ground. 4500hp of E8, and you’d have only eight. Given the per-driven-axle loading is somewhat the same, you either could start more load or, more importantly here, overcome a higher rolling resistance (curves and grades) for the same static load with the F’s at 12 powered axles.

Starting TE actually is about the same between an E8 and an F7, if I remember right, so theory says they each can only start (overcome the static resistance of load and rolling resistance of a train) the same load per unit, horsepower immaterial . Continuous TE is actually less on an E8, so it’s ability to continuously overcome the over-the-road rolling resistances like gradient and curvature is actually less per unit than an F7. (Those are “stock” numbers; add ballast and the axle loadings change so simplistic again.)

So, what does horsepower give you? While TE defines how much static (trainweight, rolling resistance of bearings) and dynamic rolling resistance (curvature, gradients) you can overcome, horsepower defines how fast you can move that same “load”. Lets flip our example a bit and assume that same (simplistic) powered axle loading. 12 powered axles of F’s at 4500hp now compared to 12 powered axles of E8 at 6750hp. Again, simplified, the two will be able to start the same load (overcome the static resistance) and maintain its motion (overcoming the dynamic resistance through grades, curves, &c, though the Es a little less in reality.) The fun bit is, for the same resistance encountered at a given moment, more horsepower means you can move that load faster. Importantly, not more load, but the same load faster.

As another example, this all makes sense out of why mountainous PRR went for C-C road units (more powered axles) in the second generation while flat NYC went for B-B road units of the same horsepower. TE is how much you can start and move; HP is how fast you can make it go given you can move it.

Eyes glazed over? See? I told you not to read this. Grin!
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E7
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Re: Question for SF (warbonnet) freaks

Postby E7 » Sat Dec 04, 2021 9:39 am

Nope, bright eyed and bushy tailed (which may have more to do with the time of day LOL) but it makes sense of a LOT of things!

Thanks Sarge!

PS, I have obviously NOT seen a lot of SF E8 Pics. I confine most of my lust East of the Mississippi river. That said, I think the Milwaukee Road is really interesting, and like the WP and NP (green main street of America color schemes.

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Re: Question for SF (warbonnet) freaks

Postby sleepmac » Sat Dec 04, 2021 10:12 am

Sarge, thank you for the explanation.

Dan Weinhold :)

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Erik C Lindgren
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Re: Question for SF (warbonnet) freaks

Postby Erik C Lindgren » Sun Dec 05, 2021 9:02 pm

Great stuff Sarge, 8)

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Erik C Lindgren
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Re: Question for SF (warbonnet) freaks

Postby Erik C Lindgren » Sun Dec 05, 2021 9:06 pm

Those odd E8s were called E8Ms. Look at the trucks for the round journal box covers for an E1 flashback. Sort of sucks they didn't at least keep one emc intact for the sake of history.. b&o did. Good for them. I know it was all taxable assets and it was bad business to keep old crap around that didn't make you a buck.

Image

https://www.railpictures.net/viewphoto.php?id=479860

https://www.railpictures.net/viewphoto.php?id=479860

Image

https://en.wikipedia.org/wiki/EMC_E1

E7
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Re: Question for SF (warbonnet) freaks

Postby E7 » Mon Dec 06, 2021 9:54 am

Good work on the pics Erik, brings the topic full circle!

Rich

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Re: Question for SF (warbonnet) freaks

Postby bob turner » Mon Dec 06, 2021 12:02 pm

My interest stops at the E7, but except for fuel tank skirts, I like that one. Had no idea one way or the other on number boards, but never cared for the strange ones, as on stock E8/9 and those PRR billboards. Just me.


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