Steam & Excursion > How similar are 844 and 3985's tenders

I was posting this picture elsewhere to show the poles, and noticed how similar the two tenders are.  Obviously not identical, but it got me to wondering how similar they are.  Just idle curiosity.

JBWX



Edited 1 time(s). Last edit at 05/17/16 13:39 by jbwest.

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Nice photo!

Very similar.

What was with the idea of having all the axles?

Having been inside of both (for a Looooooonnnnnggggggggg, Long time), I will take a swipe at this;

The cast steel centipede base is the same for the 3900, 4000 and 800 class.  If you look at your picture, you will see that the dimensions of the 800 tender is different from the 3900 and the 4000.  The 844 has much more curvature on the top of the tender.  The 3900 tender has much more flat and then curvature at the top.  The gangways, draw bar pockets and coupler heights are all almost identical, for all three classes.

Keep in mind, when the last 800's 3900's and 4000's were designed by Otto Jabelmann the intention was to make as many items as interchangeable as possible.  So, many of the castings were used for multiple units.  Not all of them are interchangeable, but a large portion.

I hope that helped.

 

Since I am here....

Axle loading.  On any piece of RR equipment we strive for equal axle loading and Not To Exceed weight limit on each journal or each axle.  To haul the amount of water, fuel and steel of these tenders, it requires a larger number of axles to keep axle loadings where they need to be.  

I have been told that the Big Boy was limited to certain lines because bridge loadings could not withstand the weight, not of the engine itself, but of one of those tenders. That suggets to me that, fully-loaded, the Centipede tender on a Big Boy weighed more than a fully loaded tender on the late-model 800's. 

1941 Locomotive Cyclopedia has this Advertisement in it for the New Commonwealth Tender Bed.  The Advertisement has about 3 pages.  I am only including this page.   There is a cast steel bed shown in the picture.

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If I remember correctly at the time the picture was taken the 3985 was coal and the 844 was oil, did that affect the tender design very much.

JBWX

jbwest Wrote:
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> If I remember correctly at the time the picture
> was taken the 3985 was coal and the 844 was oil,
> did that affect the tender design very much.
>
> JBWX

Well yes, since one had an oil bunker installed into where the coal WOULD have been. That is exactly how the tender on 3985 was converted to oil burning, i.e. remove all that "coal stuff" and drop the oil bunker down into the coal area. Otherwise, the tender remained unchanged.

Bill,

More so that the total weight of the Big Boy and Tender combined in the wheel base length was too much.   When you consider 1.1 Million pounds in a distance of about 110 feet (combined wheel base length +/-) that is where the issue is.   

No. Weights were too similar to make that much difference. The only thing where tenders would come into play would be whether or not it would fit on a turntable.

Look at how many lines 800, 3700, and 3900 engines ran all the time but 4000s didn't. With essentially the same renders as the 4000s. Tenders had nothing to do with where 4000s could or could not go.

When converted to oil, the tenders were lighter than with coal. The stoker engine, driveshafts, gear boxes, auguers, trough, heavy mounting pads, etc. were removed. Even accounting for the weight of the oil tank itself, the converted tenders were lighter than before.



Edited 1 time(s). Last edit at 05/17/16 15:28 by Realist.

Realist Wrote:
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> No. Weights were too similar to make that much
> difference. The only thing where tenders would
> come into play would be whether or not it would
> fit on a turntable.
>
> Look at how many lines 800, 3700, and 3900 engines
> ran all the time but 4000s didn't. With
> essentially the same renders as the 4000s. Tenders
> had nothing to do with where 4000s could or could
> not go.
>
> When converted to oil, the tenders were lighter
> than with coal. The stoker engine, driveshafts,
> gear boxes, auguers, trough, heavy mounting pads,
> etc. were removed. Even accounting for the weight
> of the oil tank itself, the converted tenders were
> lighter than before.

I was reading this thread and immediately began wondering the weight difference between coal and oil, and before I get to the bottom here is the answer.  I gotta thank all of you experienced folks who answer so many questions that many of us have. 

For all of the complaining that some people do about all the UP steam threads, I for one have learned so much about how steam operates from the discussions about what is being done to UP steam now and what should be done.  For those of you steam guys routinely commenting on these threads, thank you!

Those centipede tenders came in "many colors.."   I just received Tom Gerbracht's book, "Know Thy Hudsons" which of course is about New York Central's Hudsons.  There is a section covering tenders, and there were no less than four different models of centipedes, or "PT's" as they were known on the Central.  There were two other models different from these four, for the Niagaras.  No oil involved, they were all coal.  That makes me ask what the coal/water capacities were for the UP Big Boys and Challengers were.   If anyone is interested in further tech details, I can supply a link to NYCS tech data.

Wonder how much lighter 844's tender is with all the "wastage" inside?  Hope the three tenders stay with their respective engines.  Just sayin..............

nycman Wrote:
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> Those centipede tenders came in "many colors.."  
> I just received Tom Gerbracht's book, "Know Thy
> Hudsons" which of course is about New York
> Central's Hudsons.  There is a section covering
> tenders, and there were no less than four
> different models of centipedes, or "PT's" as they
> were known on the Central.  There were two other
> models different from these four, for the
> Niagaras.  No oil involved, they were all coal.
>  That makes me ask what the coal/water capacities
> were for the UP Big Boys and Challengers were.  
> If anyone is interested in further tech details, I
> can supply a link to NYCS tech data.

According to Kratville's book on the 4000 class, the tender capacities, as delivered were:

1) 4000 thru 4019 = 24,000 gallons and 56,000 lbs "level full", i.e. 28 tons.
2) 4020 thru 4024 = 25,000 gallons and 56,000 lbs "level full", i.e. 28 tons

In later years coal boards were added to most all coal tenders, increasing the capacity by some 3 to 5 tons.

I have a question regarding the first picture. When did the 3985 receive the small extension towards the back bottom side of the tender on the engineer side? I know most of the challengers received them towards the mid to late 50's. What was the purpose? More storage? I know none of the big boys received them ever.

Posted from Android

MJV1988 Wrote:
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> I have a question regarding the first picture.
> When did the 3985 receive the small extension
> towards the back bottom side of the tender on the
> engineer side? I know most of the challengers
> received them towards the mid to late 50's. What
> was the purpose? More storage? I know none of the
> big boys received them ever.

If you are referring to that "box with the big door latches", that is where the equipment is housed for the cab signal system.

When Herman Jones created the latest CCS/ATS cab signal equipment he located it in the front box on the tender. I am trying to recall, but I think the old CCS boxes were in the middle box on the tender when we restored it.

Bob Krieger
Cheyenne, WY

The very first generation of cab signal boxes were actually mounted on the front of the locomotive in a box under the running board.  Bob, your beloved Mountains have a bunch of pictures with the boxes on the front right side under running boards.  The Challengers for a short time had them and one or two Big Boys had them.   Then, UP moved all of it into the tender.  Easier to access and better place to store it.  

I went through my picture archive, and it seems to me that the major difference between the 800's pedestal tank and the pedestal tanks for the 3900'sand 4000's is that the top of the tanks for the 800's are rounded to match the curvature of the cab roof, where as the articulateds have less arch, and the top of the tender is designed accordingly so as to give a smooth line.  Or am I just seeing things?