sgriggsthe 7498hp reading has been widely reported as a continuous maximum horsepower capability of the H-8
sgriggsit was an instantaneous reading that was not corrected for acceleration/deceleration of the train
sgriggs[quoting someone else:] A dynamometer car MIGHT have revealed that 3985 was producing 14,256 DBHP [at 35 mph].
A dynamometer car MIGHT have revealed that 3985 was producing 14,256 DBHP [at 35 mph].
Dr DUnder certain conditions they did test for and got 7,498 drawbar horsepower - it is their testimony and their witness! 7,498 hp is what they had to say about their new H-8 locomotive functioning in their hands supported by their skilled professional staff - that of an entire railroad and of that present technology - the "sitz in leben" - you can review, you can look at it, think about it, but you can't go back and question their fidelity to their work.
I have a tentative comment to make.
Whether or not anyone considers 1940s-era dynamometer-car testing to be primitive, it is not a matter of religion, it is a matter of technology. What is being tested for is a matter of physics and dynamics, not establishing numbers that Lima engineers can weep over, and the results are data, not 'facts' as "dingen an sich" (to continue with the German terminology...)
I think it is abundantly clear that this 7498 dbhp number is no more an 'achievement' than the nominal 126.1 mph "attained" by Mallard during her record run. And all you have to do to find out, with the available 1940s technology, is to take your little planimeter and integrate even a short distance on either side of the peak measurement, using the C&O data and measurements that were the test department's ACTUAL 'fidelity to their work'.
I have a personal objection to introducing religious metaphors of belief into science in general, and into scientific locomotive testing in particular. While I don't ask that anyone else share that preference, I do ask that the use of terms like 'fact' be justifiable with actual methodological back-up, not just the logical fallacy of a resort to argumentum ad auctoritatem
(I'd love to find out that an Allegheny would produce 7500 dbhp. Or that one of the PRR T1s went over 130 mph, or for that matter that PRR 7002 went 127 mph or NYC 999 112 mph. But you will have to substantiate how it did, not just say in essence that you personally believe it did (or did not, for that matter), so everyone else should accept it as self-evident. In part, that means that if you want to 'cherry-pick' the raw data, you must tell us the grounds on which you do so, not just present the analysis of the selected or groomed data as 'fact'...
[Now let me play devil's advocate for a moment. It might be noted first that the original test figure for the N&W A was never even approached again in subsequent testing. And we had PM Railfan remind us a couple of days ago that the dbhp (or ihp) of an AMC Berkshire was much greater than 'common wisdom' (at least some of that derived from some kind of test reporting) said it was. Now, if we use PM's figure for the Berkshire ... and consider the Allegheny as if it were "one and a half Berks" in most operational respects ... I don't see a reason to arbitrarily rule out horsepower in the rough 7500 range, necessarily, although I do think that the 7323 or whatever that is commonly quoted as sustained horsepower is a better number to advocate.
It's just that extraordinary claims sometimes require extraordinary evidence...]
My point earlier (and I think GP40-2 more clearly stated it) was that the 7498hp reading has been widely reported as a continuous maximum horsepower capability of the H-8, when in fact it was an instantaneous reading that was not corrected for acceleration/deceleration of the train. It's therefore not a legitimate reading of the continuous horsepower capability of the locomotive. I came across an interesting 2005 posting on a Yahoo Groups thread that illustrates why uncorrected DBHP readings can be misleading:
" In 1990, 3985 pulled an American Presidents Line stack train up the 0.7% grade at Archer, WY. As the engine reached the top of the grade it was making 35 mph. This train consisted of 143 cars and 7657 tons. Incidentally, this train had been brought east into Cheyenne by three Dash 8-40C diesels. Applying the standard train resistance formulas used by W.L.Withuhn in his article projecting the HP capability of GS-4 4449 in the June '77 Trains, the train's resistance at 35 mph was an amazing 152,753 lbs meaning that an engine would have to exert that much force to achieve a SUSTAINED 35 mph on that grade. A dynamometer car MIGHT have revealed that 3985 was producing 14,256 DBHP. Except, of course, that 3985 was getting an assist. Another engine ahead? No. It was on a momentum grade. Prior to climbing the 3 mile 0.7% grade, 3985 rolled down a similar 0.7% downgrade reaching a speed of 48 mph before encountering the upgrade."
source: https://groups.yahoo.com/neo/groups/Classic_UP/conversations/topics/938?var=1
This example, along with reporting indicated horsepower, test plant horsepower, or boiler horsepower as directly comparable to corrected drawbar horsepower is what I think needs to be better identified as to the circumstances under which they were collected. These measures of locomotive capability are not directly comparable to each other.
In my opinion, as a true measure of locomotive power output, the New York Central had a very good process. They coupled the locomotive under test to a dynamometer car at the head end of a train that was too heavy for the test locomotive to pull. A second locomotive was coupled into the train to provide just enough assist to keep train speed constant at the desired speed. That way, train speed could be kept constant and drawbar pull under steady state conditions could be measured.
I don't want my comments to be taken as a criticism of the railroads whose testing did not follow this practice, as I recognize their objectives may have been different. Many roads ran tests differently to establish tonnage ratings over specific runs, and not with the explicit purpose of measuring DB pull or horsepower under perfectly-controlled conditions.
Timz,
What I put in quotes above is directly from the test report summary, hand numbered page 3. If we believe that Run 106 is accurate, it was westbound from Russell to Robbins with 13,650 tons. If we believe 7,498 max DBHP to be accurate, this occurred on Run 104 westbound from Russell to Columbus with 14,075 tons. There's a discrepancy between the test report summary and the individual run data pages. Oh, the joys of locomotive test reports.....
timz,
HA! Seasons greetings to you my friend!
Dr. D
Dr Dyou can't go back and question their fidelity to their work. Timz, thats my point!
Did C&O ever say, in so many words, the 2-6+6-6 was doing 46 mph northbound with 14075 tons at MP 61 plus 1400 ft? If so, we'll question that.
GP40-2,
This is exactly my point on "timz" criticism of the reported horsepower figure of 7498 hp for C&0 H-8 Allegheny.
The use of the dynometer car in the 1940s was nothing like today with the ability of computorization to digest insurmountable mathmatical problems. In those days a team of railroad engineers and technicians worked at the math with slide rules and sheets of pen and paper. Each dynometer car had a full time staff to compute mentally and recieve reports from the locomotive engineer by telephone. Observers watched out the window or cupola to locate the railroad and mile post. Data was recorded on rolled paper reel chronograph with 6 ink filled fountain pens! Accurate record of the distance the train traveled transfered to the rolling paper real - whose accuracy was imperative. Because all the calculations were based upon the rolling paper trail - was by car wheel with drive shaft to the rolling paper chronograph table. The travel of the paper was proportionate to the distance of the locomotive, and the work in foot pounds was directly calculated from the "area of the figure described" between the drawbar pull line and the datum line. Measurement based on the computation of a pen scribble between two lines on a paper!
This "drawbar horsepower" measurement is primitive to say the least just as was "indicated cylinder hosepower" based upon the mechanical drawing made by the valve action of the locomotive on a "paper card" with a pen. Run as many cards as you want - lets see if we can get ONE we like!
Lets see if we can get that locomotive pulling real good and see what kind of trace we can get of it on a rolling paper table! Lets see if we can get ONE we like - do you believe we got ONE trace where she pulled 7,498 hp!
It was the challenge of the test crew just to get the locomotive in a test situation where it would actually operate at its maximum capability. The professional skill of the engineer and fireman was being tested also. Many tests would be made but was the engine actually operating in a full power mode? Given the test parameters and conditions I am not sure they ever got the operational conditions they desired. Science and engineering being what they were in the 1940s.
J. Parker Lamb in his book Perfecting The American Steam Locomotive explored just this concept - that the age of "Industrial Science" was not yet fully developed, that the steam locomotives were in part a product of the age of "Industrial Arts!"
Modern scientific re-evaluation of these old tests - with only so much critical review - it is just not possible without going back - without doing it all over again.
Ralph Johnson steam design engineer for Baldwin notes, "For the calculation of drawbar pull-speed characteristics of a given type of engine, methods have been described...The determination of such curves in the field is quite laborious unless grade and alignment conditions are favorable. If the actual performance is considerably below the standard the reason may be disclosed by inspection of the locomotive or a study of the methods used by the engine men."
The subjective element is here - favorable conditions! I am not sure if C&O ever got a true idea how much power the H-8 could develop. Under certain conditions they did test for and got 7,498 drawbar horsepower - it is there testamony and their witness!
7,498 hp is what they had to say about their new H-8 locomotive funtioning in their hands supported by their skilled professional staff - that of an entire railroad and of that present technology - the "sitz in leben" - you can review, you can look at it, think about it, but you can't go back and question their fidelity to their work.
Timz, thats my point! And Lamb notes, "Some Lima engineers wept for joy, that they bested N&W class A!" And how shall WE ridicule that!
GP40-2:
According to my understanding of the situation, you are correct. The information was evidently destroyed. I do not fault the authors for their inability to find the unfindable. My complaint had to do with information that can be discovered through careful examination of available dated photos. It is clear that the first 7 EM-1 engines differed from the next 13, and you don't need those lost records to discover that.
Tom
ACY The book is not terrible. It's a nice collection of photos, with some very interesting locations. But the reproduction, as I said, is pretty poor, the binding is poor, and the missing information is an irritation to me. The EM-1 deserved better treatment. Tom
The book is not terrible. It's a nice collection of photos, with some very interesting locations. But the reproduction, as I said, is pretty poor, the binding is poor, and the missing information is an irritation to me. The EM-1 deserved better treatment.
That book is the best you are going to get on the EM-1. There isn't any more information. When the B&O started scrapping the EM-1, they threw out all the testing data. Literally, hundereds of pages of test data gone. Back in the 1970's a retired B&O mecahnical engineer that I knew told me when the B&O made the decision to move to diesels, entire file cabinets of steam test data was thrown out.
Dr D timz, I am sure that when C&O railroad officials, and those who spent weeks developing the testing of 1600 series locomotives, to say nothing of thousands of employees involved in steam locomotive design finished their work and reported their findings, well! I am sure that they were all thinking - that in the year 2014 a guy named "timz" would question all their work and decide it was a capricious overstatement and lacked integrity, fidelity and honisty in reporting. It is what it is! Appreciate it, Live with it! Dr. D
I am sure that when C&O railroad officials, and those who spent weeks developing the testing of 1600 series locomotives, to say nothing of thousands of employees involved in steam locomotive design finished their work and reported their findings, well!
I am sure that they were all thinking - that in the year 2014 a guy named "timz" would question all their work and decide it was a capricious overstatement and lacked integrity, fidelity and honisty in reporting. It is what it is! Appreciate it, Live with it!
It is not that the C&O, or for that matter the N&W, PRR, UP, etc, didn't report exact data. What the issue is how rail "historians" are incorectly interperting that data and the context it was taken in. The trouble is that many books and articles have been written by individuals who have no clue what they are looking at. They see a number, mix and match other numbers, guess at what it means, then write a book. If that fails, they just make something up to suit their needs.
Probably every book I have ever read in the railfan press about locomotives is littered with inacurate statements and "facts". Nevermind many of those "facts" are scientifically impossible. Timz is rightfully questioning some of the long held facts that many railfans belive just because they read it in some book.
No need to "understand the circumstances". If we believe the Davis formula, and if we believe the engine reached 46 mph with 162 cars, 14075 tons at MP 61 plus 1400 ft, then it was sustaining 7000+ dbhp.
So maybe we shouldn't believe any of that. Did C&O for sure say the 46 mph was with 14075 tons?
Thank you for the information. I was surprised by the low average speed (29mph) for the total run, but 14075 tons is a relatively heavy train. I agree with your statement about the train getting an assist from gravity. The Davis equations and DB pull plots for the H-8 suggest it couldn't reach 46mph on a level grade hauling 14000 tons. I think it's unfortunate that the 7498hp number has taken on an aura of legitimacy among people who are not careful to understand the circumstances under which it was measured.
feltonhillI believe the train was coming out of a sag, so the 7,498 [dbhp] figure may be just a bit overstated.
(So did they know them? Good question. The chart says the engine was on +0.16%, so the grade correction is +1500 lb or so-- corrected drawbar pull is 1500 lb more than the measured pull. If by chance they were decelerating at 0.1 mph/sec at that point then that correction would be minus 4700 lb-- so would be nice to know whether they took that into account.)
In any case, the 7498 figure isn't of much interest. Who cares what the engine can sustain for two seconds? If it can maintain 7000 dbhp for two minutes, say, then that's interesting. If it can maintain 6700 dbhp for 10 minutes, or 6500 dbhp for 30 minutes, then that's interesting. But in the US, at least, road tests never keep such records.
Here's what I found regarding the 7,498 DBHP figure. From the test report:
"Inspection of the final results of all the test trips showed the machine frequently developed a sustained drawbar horse power of 6,700 to 6,900 at speeds of 42 and 46 miles per hour., with a back pressure of 20 pounds or higher. The highest instantaneous draqwbar horse power occurred on test run No. 106 at mile post 61+1,400 feet, at which time a maximum of 7,498 drawbar horse power was developed at a speed of 46 miles per hour."
I looked at the track charts (C&O page numbers 154 and 155 for those who may have them) and found that there is a sag on either side of MP 60. So the train was getting some assistance from gravity to achieve 46 mph. If you look at Huddleston's scatterplots, you'll notice that both the DB pull and DBHP curves have two outlier points at about 46 mph indicating that something was going on to achieve those readings. In order to evaluate each point, you have to know the the exact location where the reading was taken. I haven't found that kind of detail in the papers I have.
Next topic, coal and water consumption. These quantities are listed over a total run, and no short term readings were included in the test report. Also, the peak reading of 7,498 DBHP is atributed to test run No. 104, not 106. Don't know the answer to that one. Here's what an average of three runs, WB Russell to Columbus look like.
Distance - 109.85 miles
Totla time - 4'43"
Run time - 3'47"
Working time - 3' 27"
Coal, total - 46,468 lbs
Water - Total tank - 37,166 gal
Total including condensate - 39,856 gal.
Average DBHP - 4,516
Maximum DBHP - 7,150
Maximum sustained DBHP - 7,060
Hope this helps.
Yes, the H8 tests exist at C&OHS archives. I also happen to have a copy here. IIRC, the steam production and coal consumption rates were relatively moderate, indicating that the H8 on test was not being flogged to reach that figure. Also I believe the train was coming out of a sag, so the 7,498 figure may be just a bit overstated. I'll see what I can dig up later today.
Here's a question for you H-8 Allegheny experts. I'm told the test reports from the 1943 dynamometer testing (the tests during which the well-quoted 7498 DBHP measurement was taken) exist in the C&O Historical Society archives. I have both Huddleston books (The Allegheny--Lima's Finest, and Worlds Greatest Steam Locomotives), but neither seems to go into detail about coal consumption and steam production during these tests.
If anyone has access to the test reports, can you tell me what the firing rates (lbs/sq ft grate area/hr) were? If this is not available, an average firing rate can be calculated from the total coal burned (lbs) and the total running time of a given test run.
Thanks in advance!
PM Railfan ... one thing to consider, are you talking boiler hp, or drawbar hp? I'm talking drawbar hp.
Boiler HP isn't a measure of concern on locomotives; it's based only on heating surface area and really doesn't tell you anything valid.
What you're referring to is 'indicated HP' (also known as 'cylinder HP') which is correctly mentioned in the subsequent posts. This is a measure of the physical power developed in the 'engine' (or engines, in an articulated). There's an interim measure taken at the driver wheelrims (net of all the losses and nonlinearities caused by the drive), and then there is drawbar HP which includes the other machine losses of the locomotive. (Note that DBHP on a grade, or when transiently measured during acceleration/deceleration, also reflects the mass of the locomotive.)
[quote user="thomas81z] http://www.amazon.com/Baltimore-Magnificent-2-8-8-4-Articulated-Locomotive/dp/0939487837 Wow the lowest price is 212.00 wow to steep for me Though i would love a copy someday [/quote]
Ebay has a slightly lower one - $160 plus $4 shipping:
If $212 is not in your budget, I have some words of comfort: The book has some serious issues.
First, the photos are not well reproduced.
Second, the binding is not very good. Pages tend to fall out of my copy.
Third, some very interesting facts about EM-1 detail variations are completely ignored. For example, the book ignores the fact that the first seven engines, 7600-7606, differed from 7607-7619. These diferences would be of particular interest to modelers. The first order should probably be separated into group 1A and 1B because the first seven of the first order had a different sandbox arrangement. The book ignores the modifications made to 7608's sanders circa 1950. It also glosses over the different routing of feedwater piping on 7600-7619 before and after modification, vs. 7620-7629.
The book would have served modelers far better if it had mentioned and illustrated the very unusual and interesting whistle linkage, which has very rarely been modeled correctly.
$200 is way too much for this item, so be happy you saved the money.
Overmod WILLIAM ABEL Just like it is almost a crime that the Pennsylvania Railroad didn't keep just one T-1 (or the S-1 and S-2, or a J-1, or a HC-1, or.......). There is correspondence in the surviving PRR files at the Hagley Museum that specifically concerns preserving the S1 "Big Engine" for the Northumberland collection. I came across this while doing research on the V1 turbine, and didn't make careful notes -- but at the time the S1 was considered second in historical importance only to the 'Lindbergh engine'. The problem was that the scrap value was something like $37,500 (the rough equivalent of a million in today's money) and management thought it would be unfair to the stockholders (with the railroad doing relatively poorly at the time) not to recover that amount for them...
WILLIAM ABEL Just like it is almost a crime that the Pennsylvania Railroad didn't keep just one T-1 (or the S-1 and S-2, or a J-1, or a HC-1, or.......).
There is correspondence in the surviving PRR files at the Hagley Museum that specifically concerns preserving the S1 "Big Engine" for the Northumberland collection. I came across this while doing research on the V1 turbine, and didn't make careful notes -- but at the time the S1 was considered second in historical importance only to the 'Lindbergh engine'. The problem was that the scrap value was something like $37,500 (the rough equivalent of a million in today's money) and management thought it would be unfair to the stockholders (with the railroad doing relatively poorly at the time) not to recover that amount for them...
A drop in the bucket as assets went even in those days. They were foolish not to keep it, and a T-1 and maybe the S-2 as well. C'est la vie.
thomas81z http://www.amazon.com/Baltimore-Magnificent-2-8-8-4-Articulated-Locomotive/dp/0939487837 Wow the lowest price is 212.00 wow to steep for me Thou i would love a copy someday
http://www.amazon.com/Baltimore-Magnificent-2-8-8-4-Articulated-Locomotive/dp/0939487837
Wow the lowest price is 212.00 wow to steep for me
Thou i would love a copy someday
Forget Amazon! Take my advice, prowl the train shows, used book dealers, flea markets and antique shows, and so on, and keep your fingers crossed. You might get lucky! I have on numerous occasions.
$212 for a paperback? Which is probably going to self-destruct in 20 or 30 years time like a lot of paperbacks do? That 's nuts!
By the way, the most I've ever paid for any book was $75 for a book printed and published in 1847 of correspondence between New Jersey patriots during the Revolutionary War. Yep, ol' General George was in there too. The condition of the book was like it was printed yesterday, you can still feel the indentations from the printing press in the letters.
I passed on it the first time I saw it, then was in the same book dealer a year later and it was still there. Well, I know a sign from above when I see it, so it went home with me. I'm not sorry either.
I heard a similar story many years ago and finally just walked into the B&O Museum and asked them outright about the EM-1 rumored to be stored in some back lot. They said that it was there for a short time back in the late 50s and then got scrapped.
I saw an EM-1 once as a small child in Ohio. I was used to seeing the B&O Mikados and the one thing I remember is how big this thing was compared to them - especially the tender. What a shame that they didn't keep at least one of them. Just like it is almost a crime that the Pennsylvania Railroad didn't keep just one T-1 (or the S-1 and S-2, or a J-1, or a HC-1, or.......). Well, getting back to the H-8 issue - hey, if they can rebuild a Big Boy, why not an Allegheny?
PM Railfan,
Thanks again for the thoughts. Here are three great historic reads.
Alfred W. Bruce - The Alfred Bruce book, Steam Locomotive in America was published in the 1952 by Norton Press. Written by just retired American Locomotive Company - (Alco) design engineer Alfred Bruce. It is a pretty well written evaluation of design history of the American Steam Locomotive with builders photos of most representative American steam power. He leaves out the science and math but really addresses historical development of locomotives individually and particularly. For example the number of each locomotive wheel arrangement produced over time. Mikado engines in the thousands, Hudsons in the hundreds Northerns in the hundreds, Big Boy's only 20 etc. Good technical data on each locomotive included in photos. A nice rendition of the Pennsy duplex development along with who developed the first in each class. Who did the Northern and story of the first one.
Surprisingly some of these photographed engines still exist - builder photo of UP 9000, 4-12-2 and last domestic production C&O 1305 2-6-6-2 to name a few. This is a good historic work made by one of the engineers designing locomotives in the 1940's. This book is widely available on the internet by just Googling the author and title. Price is in the $50 range.
Paul Kiefer - Second is Paul W. Kiefer, A Practical Evaluation of Railroad Motive Power, published by Simons-Boardman in 1949. Paul was the head steam design engineering executive for New York Central, yes the man who was building the Hudson and Niagara. His book is the follow up of a speech he was asked to give in England to steam producers. Formally presented he shows his fine education as he tried to make a case in print for steam locomotives showing on a cost for cost performance basis how American steam was getting a bad rap from GM and the Madison Ave. sales pitch crowd. To be objective Kiefer presents a review of electric locomotive and diesel power in comparison to steam. He makes a pretty case to the rail executives of the 1940's about what steam still could offer in the future. Trouble is no one but Norfolk and Western was listening.
Kiefer is basically a presentation to professional railroaders. About a hundred pages with one black and white plate in the beginning of a Niagara 4-8-4, Burlington FT diesel and Pennsy GGI electric. I wanted this book for years and it occured to me to look on the internet about a month ago. This one I bought for $50 was stamped as purchased for and was a part of the Virginian Railroad Company library.
Ralph P. Johnson - The Steam Locomotive Its Theory Operation and Economics, first edition in 1942 and expanded in the second edition in 1944. Johnson was a chief design engineer for Baldwin Locomotive Works. He answers all the questions that the railroads kept contacting him about durring WWII. How to balance locomotive drive wheels and rods - all the math and formulas. Everything you wanted to know scientifically about water and coal for the working steam executive and shop forman. Chapter on the complexity of Evaporation from the boiler and its science. Combustion and all the science of what happens when coal burns including the chemistry of it. Superheat steam in all its science, what is "Type A" and what is "Type E" superheaters in detail. Locomotive test procedures, streamlining from a scientific perspective, braking and acceleration. Tractive force, high speed trains and dynometer cars etc. Many detailed drawings are included in the pocket of the book.
I picked up this copy on the internet a couple of weeks ago but it will take a lifetime of continual reading to understand it. My copy was signed by Ralph Johnson and given to a sales executive of ALCO named Fred S. Broadbent. This one ran about $150 because it was signed by the author. The second edition of this book includes many chapters not in the first edition.
Ralph Johnson was the engineer and driving force behind the Duplex drives that were built for the Pennsylvania Railroad.
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Here is a chance for you to pick the brains of those mid 20th Century engineers who were on the top of the steam locomotive building. Most of these guys were the children of the Civil War generation and rode the industrial revolution pioneered by railroading. They lived to see the invention of the airplane, internal combustion engine, automobile, electric lights, photography, sound recording, radio, television, and atomic power.
Just as you and I have seen space travel and the information age.
Dr D. - your most welcome.
Another stat packed post (YES!), yet it was saddening. Why? Because it is only "you and I" left to discuss and ponder the great work by men like Johnson, Woodard, Kiefer, et al.
What i wouldnt give to sit down and pick their brains in the most technical talk ever had this side of a lunar mission. Can you imagine the stuff we dont know that they didnt write down?
We really do owe alot to these fellows, and the authors who have put their work into writing so you an I today, can even have this conversation. Makes me wonder sometimes.... do you think they ever thought a bunch of railfans 70 years in the future would be discussing their work in detail? Hashing numbers, critqueing designs, or just plain drooling over some of Dreyfuss' work. Or Lowry for that matter even.
I wished I woulda known you were gonna type all that about loco testing. I coulda saved you the hassle. I summize, like you have, I have read alot of data about loco testing and all the variables inclusive. Seems that "all the stars' had to be perfectly aligned during these times huh? Some call it dry/boring reading. I call it a life requirement. But then, you and I are biased.... were railfans.
Also, thanks for posting authors and book titles. They will make nice additions to my book collection should i come across them. I am looking forward to reading them! I have studied alot over the years, but there is sooooo much more to know still. Many more books to read, diagrams to study, reports, stats, etc etc.
Problem is, i dont know about you, but memory and eyes are failing. Only have so much time left.
Your absolutely right - in a world of cold boilers and tombstones, its only you and I! So keep the stats coming! GREAT stuff!
Cheers!
Thanks for the compliment.
Ralph Johnson design engineer for Baldwin Locomotive Works in his book The Steam Locomotive discusses the ways in which steam locomotives were tested. This was not an easy task as the locomotive was required to be in peak condition with five or six major parameters considered - effective functioning boiler - no steam leaks in cylinders etc. Consult his book for an extensive evaluation procedure. Also the quality of water and coal was extremely important as was water level in the boiler, and a host of other considerations like the ability of the engineman and fireman etc.
In addition he points out the "indicated cylinder power" was determined mathmatically using the technology of the time. "Drawbar horsepower" depended on the quality of the test car and was measured by the pull on a trapped spring connected to the tender drawbar. Many variables were introduced in this test procedure and consistant results varried on each test let alone from railroad to railroad.
Third is "dynometer plant testing" such Pennsylvania Railroad and Purdue University had equipment to perform. In this case the locomotive was held fixed over rotating drums and the wheels spun against a load. Wheel slipage, and many other variables effected this testing, to say nothing of how few locomotives could be tested this way and the cost. What an investment Pennsy made!
For this reason and the lack of a standard testing procedure such as provided in the automotive world by the Society Of Automotive Engineers. This means that measuring locomotive power for many reasons was somewhat subjective. In any reasonable fashion or form of the time its results were in a degree questionable.
I do feel that professional railroad engineers of the time made every attempt to communicate their power evaluations in an honest and meaningful fashion - how shall we question their work? - we cannot go back and talk to them, we can only take what they sincerely did at face value. Neither you or I can add to this discussion more or less than these published facts. The performances, however, speak for themselves!
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The figures of NYC power were taken from Paul Keifer's book A Practical Evaluation of Railroad Motive Power. Kiefer was the design engineer for New York Central steam power.
He lists the Niagara 4-8-4 as the most powerful locomotive NYC ever produced,
"With 79-in. diameter wheels and the present working pressure of 275 psi, Table 1 shows that a maximum cylinder horsepower of 6600 was obtained at 85 mph, with corresponding maximum drawbar horsepower of 5050 at 63 mph. With a working pressure of 290 psi, for which the boiler is designed, these figures become, respectively, 6900 and 5300, with 75-in. diameter wheels, when operating with 275 psi boiler pressure, the maximum cylinder horsepower is 6600 at 77 mph, and the drawbar horsepower is 5200 at 61 mph."
Kiefer further notes in his SUMMARY OF PRINCIPAL CHARACTERISTICS OF RECIPROCATING TYPE LOCOMOTIVE DESIGNS DISCUSSED,
NYC K-5 4-6-2 at 3000 horsepower
NYC J-1 4-6-4 at 3900 horsepower
NYC J-3 4-6-4 at 4700 horsepower
NYC L-3 4-8-2 at 5200 horsepower
NYC L-4 4-8-2 at 5400 horsepower
NYC S-1 4-8-4 at 6600 horsepower
New York Central did extensive testing using dynometer cars and cylinder indicator measures as well as mathmatical calculations measuring work done.
--------------------------------------------
Figures given for the other locomotives were taken from J. Parker Lamb Perfecting the American Steam Locomotive.
Figures for the ATSF engines were taken from ATSF locomotive test reports published by S. Kip Farrington, Jr. in Santa Fe's Big Three. ATSF used figures generated by dynometer car testing performed by the railroad.
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So there you have it! The boilers have long since gone cold. The great engines scrapped or preserved in museum or park! Those who engineered and designed are long dead. Those who knew the technology and drove the engines are also long dead. Who has the ability to re-evaluate the hard work and results so ardiously achieved. NO ONE!
It remains only you and I - it remains only for you and I to appreciate their efforts, those long gone! And to celebrate the visions of railroad transportation they had! - Yes, only you and I - only you and I remain to tell the story!
Dr. D.
Dr D - 25 of the 60 Alleghenys were equipped with steam/signal lines for pasenger service. Though limited to heavy mail and troop trains. Unknown if they ran with 'named' passenger trains (Sportsman, G. Wash., etc.). Never seen photographic proof of this actually happening.
Im not sure if you mistyped a little bit... but NYC Niagra as a 4-6-4? Im pretty sure those were Northerns, and their Hp rating is in the 5000 range, not 6000. Same goes for the N&W J, SF and UP Northerns as well. Northerns werent that much more powerful than your Berkshires, which came in at around just barely shy of 5000hp. (one thing to consider, are you talking boiler hp, or drawbar hp? im talking drawbar hp.)
Engine weight for an NYC Hudson was 370,000 (J1 to J3a) not 265,000lbs. More typos maybe?
More to your point of bending rails, the axle loadings on the lead driving axle of an H8 (1600 - 1645) was just shy of 87,000lbs. The SF Northern is 77,500. Both higher than you listed, but still 10k difference. Indeed, rail benders and bridge breakers they were! Incidently, the pilot truck of an H8 was 71,000 lbs. More than some axles loadings mentioned.
Im gonna check the axle loadings of the UP 800's vs Big Boy, you got my curiosity peaked on that one! Love researching the stats!
Great post!
PM: Not quite. Strasburg Rail Road is older than U.P. and has never changed its name, although it has changed ownership. IIRC, Union Pacific Railroad Company was once known as the Union Pacific RailWAY. But it's true that both of them run steam!
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