GP40-2I wouldn't consider the Big Boy scaled up at all. It was only 6 feet longer than the EM1
Surprisingly, those "smallest" Yellowstone's were even were longer than the " big"M3/M4...
For John,
here is the quote from Kratville (Ogden/Riverdale to Wasatch, distance 62miles, elevation 4355ft - 6799ft):
Engine:
4014 : 3479tons av. speed 20.2 - av. draw-bar pull 64400lbf - av. DBHP 3415 (peak 5530 Devil's slide)
4016 : 3883tons - av. speed 19.5 - av. draw-bar pull 71000 -av. DBHP 3585 (peak 6290 M-P 958)
4004 : 3539tons -a v. speed 21.2 - av. draw-bar pull 64800 - av. DBHP 3570 (peak 5990 Peterson)
The runs were performed with different throttle + Reverse Lever positions ,also varying traffic occur.
That is realistic ---imo, of how much work is done, pulling such trains continuously uphill (except one mile, that is level ;-)
Hard working, they produced more than 4000DBHP at 14mph, with a load of 3883tons on 1.14% grade, so lets say 15mph speed minimum they were attempting in general on long grades. And there were certainly occasions, they lugged lower than this...
...John your figures seems to come from the "Challenger"-book...
-lars
UP 4-12-2Though it may look like a "scaled-up Yellowstone", the Big Boy was designed by Union Pacific's engineering department under Otto Jabelmann as a Challenger with two extra drive wheels. The design goal was for a Big Boy to pull the same train as a Challenger pulled over the flatter areas of the mainline, but to take it over the Wasatch mountains. Union Pacific never owned a Yellowstone. If you study the actual photographs, the UP Challenger heritage is quite obvious. Also, "3600 drawbar horsepower" appears to be a pretty low figure for Big Boys in actual operation. The Big Boys were rated to pull 4800 tons on a sustained 1% grade. This is from a Union Pacific motive power rating chart dated 1958, published in William Kratville's The Challenger Locomotive. The maximum cylinder horsepower of a Big Boy was rated at 6680 on that same chart from 1958. Obviously, drawbar horsepower is less--especially at lower speeds, but 3600 seems unrealistically low. John
Though it may look like a "scaled-up Yellowstone", the Big Boy was designed by Union Pacific's engineering department under Otto Jabelmann as a Challenger with two extra drive wheels. The design goal was for a Big Boy to pull the same train as a Challenger pulled over the flatter areas of the mainline, but to take it over the Wasatch mountains. Union Pacific never owned a Yellowstone. If you study the actual photographs, the UP Challenger heritage is quite obvious.
Also, "3600 drawbar horsepower" appears to be a pretty low figure for Big Boys in actual operation. The Big Boys were rated to pull 4800 tons on a sustained 1% grade. This is from a Union Pacific motive power rating chart dated 1958, published in William Kratville's The Challenger Locomotive. The maximum cylinder horsepower of a Big Boy was rated at 6680 on that same chart from 1958. Obviously, drawbar horsepower is less--especially at lower speeds, but 3600 seems unrealistically low.
John
UP 4-12-2If you study the actual photographs, the UP Challenger heritage is quite obvious.
Yes John, it is maybe just another point of view of mine, and the Big Boy was certainly built to UP standards, therefore its heritage...
But I am not so sure, to determine it as a scaled up Challenger. Look at GP40-2's comment above, it is basically a Yellowstone with an additional leading axle...
Hope to give support to this view: The BB was an all new design, improving the first "Baby" Challengers not just by power, also by - a new articulation design, casted frames, roller bearings, exhaust system, firebox...and more. However, the "heavy" Challengers were a scaled down Big Boy ;-)
Am I splitting hairs a bit to much of it?
lars
Good morning, Boyd, and everyone else:
I am the compiler of the data to which you referred in your post. It is extracted from a larger database that covers as many of the world's locomotives as there is data available.
Wes Barris has been kind enough to host my data for several years. In addition to devising the process through which we could post as much data per locomotive as we do, Wes flags the obvious inaccuracies and passes along comments from visitors. Please also note that he offers his own commentary about many of the arrangements and classes on the home pages for each of those sections.
During all of the time Wes has hosted the data, he has displayed my name and my email address. Several visitors to that site have contacted me through the email address with corrections, comments, questions, and points of discussion. Any of those contacts would tell you if asked that I respond positively, accept the comments willingly, and incorporate them readily.
A review of the commentary on most of the entries will show the primary source's full bibliographic cite. In addition, I will include the identity of the person who contacted me with a correction and usually will quote him or her verbatim.
In short, my door is always open and that stance does not reflect a recent change in policy.
To respond to your specific inquiry about minimum rail weight. That's an actual calculation I unearthed in the Chicago & Eastern Illinois' Data on Locomotive Equipment book dated October 1, 1912. It is admittedly a simplistic calculation:
Weight of drivers/number of drivers, which is divided by 3000. That result is multiplied by 10.
Their example is 103,000 weight on the drivers/4 drivers = 27,750.
27,750/3,000 = 8.58.
8.58 x 10 = 85.8, which the Data Book describes as weight permissible per weight of rail.
That's it. It's obviously a debatable formula, but my point is that it came from a book used by an operator in real-time railroading. I cannot tell you that those assigning the locomotives in fact believed that this was the only number they need; like you, Boyd, I doubt it. For one thing, the constant used in the calculation (3,000) undoubtedly changed at some point after 1912, or should have.
But like most of the rest of the data I've included, it's sourced and the sources typically represent my attempt to convey what operators or knowledgeable commentators knew (or thought they knew) at the time this particular class was in service. (I'll admit to exceptions to that claim and offer no excuses other than lack of editorial resources.)
As far as the minimum rail weight given for the C & O Allegheny. Doesn't the figure (141 lb/yard) underscore the weight problem that's been discussed when we take into account your comments about the actual weight/yard used at the time?
Again, I welcome any comments about any of the entries. All of the designs that have been discussed in this thread have data and commentary available at steamlocomotive.com.
Steve Llanso
Locobase
delocobase@comcast.net
Thank you GP-40 for your kind reply.
Hope you may answer another question of mine, what did they especially do enhancing the front-end?
Lars LocoThe Big Boy was just a part of it, a fast pacing-one.What I found pretty cool is the fact that the SP let them even run backwards, moving their unpivoted mass through curves...even with no roller-bearings? Leading passenger trains? Never read probs about them, though... another nice engineering ex.lars
The Big Boy was just a part of it, a fast pacing-one.
What I found pretty cool is the fact that the SP let them even run backwards, moving their unpivoted mass through curves...even with no roller-bearings? Leading passenger trains? Never read probs about them, though... another nice engineering ex.
GP40-2the Yellowstone Class was the ultimate all around heavy freight steam locomotive
Dear GP-40-2,
'44 seemed to be an interesting year, as many RR attempted to achieve ----- diesels, which were limited, although, and therefore not granted to every RR.
Their final steam-results were still impressive, based on first investment/HP, but not main- / running costs in the end (personal, I like those casted frames and roller bearings-/articulation-/suspension design).
I would better say, for ex., the Big boy were av. 3600+ DBHP engines uphill, than those allways proclaimed 6290HP peak, and this says a lot, comparing diesel like an FT or F3-threesome . Take a double headed 2-10-2 TTT uphill, that's pretty the same...
-The EM's seems to be nice engines, can you tell me more about them?
Th'x
--BTW "academic" is a fine way, calculated, theoretical or historical. Mostly I know is the last one, but tells the same story, if followed carefully like the first two ones ;-)
Lars Loco-interesting,did PRR ever had itself plans to built a own 4-8-4, or is this article based on a theoretical "what if " description? How realistic was it?lars
-interesting,
did PRR ever had itself plans to built a own 4-8-4, or is this article based on a theoretical "what if " description? How realistic was it?
I don't know if the PRR ever did seriously consider building/buying a 4-8-4. If they had an interest in the 1930's, they would have acted on it. IIRC, the PRR made an executive decision around 1944-45 to dieselize the entire operation, so they would of had no interest in a true end-of-steam 4-8-4 design such as the NYC Niagara or C&O J3a. The only reason they completed their own end-of-steam designs was because at the time they had too much R&D tied up in them to stop. Their hope was to sell them to another RR that was more committed to steam, but no one was interested.
The whole discussion about whether the N&W Class A or the C&O H8 is "better" is also academic in nature IMHO. There is a strong argument that both the N&W and C&O might of have been better off buying/building a late-steam 2-8-8-4 Yellowstone type of design for their general freight needs. Late model Yellowstone Class locomotives such as the M3/M4, Big Boy, and EM1 combined superior down-and-dirty lugging ability, high factors of adhesion, and the ability to run at high speeds in a single locomotive. While some other designs might have been slightly better in specific circumstances, in my view, the Yellowstone Class was the ultimate all around heavy freight steam locomotive.
The fact that the M3/M4, Big Boy, and EM1 lasted into the early 1960's on their respective RRs is a testament to their well thought out design.
There were at least two articles that dealt with what-if PRR 4-8-4s, but they are a long time back:
Keystone, Spring 1998, Vol.31, no.1
Keystone, Autumn 2000, Vol.33, no.3
I believe the topic of a PRR 4-8-4 was discussed in the 'Keystone' in the last few years - does anyone happen to know the Vol/Issue this article appears?
As an aside, I have really enjoyed watching this thread evolve over the last few months. Unfortunately I don't have the back issues containing many of the articles referenced. I've been keeping a eye out on eBay for back issues but I wonder if Kalmbach might consider packaging some of these into a future download package?
--Reed
Another point: The T-1 was designed to run Harrisburg - Chicago without engine change and had tenders that were supposed to handle this run without stops for refueling but with use of water track pans. In practice, engines were usually (eventually always) changed at Crestline. K-4's were never expected to run through Harrisburg - Chicago because the tenders simply were not large enough. and refuleing would have invovled as much time as changing engines at Crestline. Admittadly, the N&W J's never had a chance to perform such long distance service, but the Central's Niagras did and did so succesfully. I think the Pennsy may have experimented with a few K-4's that received tenders of the type used on the M-1, but this was towards the end when diesels were already being ordered.
Another take on the PRR steam locomotive designs: Their steam locomotive expertese may really have been dispersed with the onset of electrification. The K-5 improved Pacific program, leading to a Pacific that would truly match the Central's Hudsons, got sidetracked without the intense modification and testing that say the E-6 enjoyed. There was a program at the same time to develop a super Atlantic for lightwieght Congressionals, and this also got sidetracked.
Then came the development of the somewhat useless S-1. even more of a show-case unreal project than the C&0 2-6-6-6. In reality, the T-1 was an attempt to scale down the S-1 into something usable, and if they had started from scratch and been a bit less insular, perhaps a good 4-8-4 would have evolved. At the same time, the GG-1 was more successful than the R-1 4-8-4 electric. While other railroads were ordering streetcar-like electrics with motors on pivoting trucks geared to axles, the PRR used steam locomotive practice in the DD-1. Possbly the T-1 and the Q's reflected too much electric power influence. The more motors the better = the more cylinders the better! And possibly some of this was subconsious. Anyway, I am convinced that the PRR would have been better off with a good 4-8-4 than the T-1, and that buying Baldwin road diesels was also a mistake.
But I still appreciate the rides I had in PRR long distance coaches and once in a sleeper behind T-1's. It was a beautiful locomotive to see. Even if I like the N&W J even better,
I may be a day behind; but I wondered too about the specific rail weight. Most of the modulus of the track structure can be in decent ballast. By comparison, the C&NW Class H had 288,000 lbs on drivers and was said to be designed to run at 85 mph on only 100# rail. PRR laid some 140# rail early on, mostly in the East; but I ran across a stretch on the PFtW&C in Indiana which otherwise had 131# & 132# rail.
Dear feltonhill,
allow me to say first, to clarify, in no way my quote was intended to point critics on Wes' site, he does an awesome job there. I understand his page as a portal for browsing general infos about steam locomotives, but not all data can be compared directly ( which he points out also, many times ).
Lars,
Thanks for the link. Based on sampling most of the wheel arrangements, the formula used appears to be:
weight of rail = weight on drivers/(600 x number of driving axles)
or if you prefer:
weight of rail = axle loading/600
Never saw this formula before. I wonder where steam locomotive.com got it? Maybe it's another one of these mysterious yet simple ratios that give an answer the rest of us find too complicated to reduce to something so straightforward. Or wasn't this the underlying argument of this thread to start with? I don't like to sound skeptical so quickly, but the 600 x WOD divisor sound a little too pat for my liking. In my experience, tie spacing is also very important when it comes to supporting a given axle load. No such variable is in the above equation.
I don't regard the technical information on that site as all that good, although it's a convenient source to get a lot of stuff in one place. Unfortunately, I've found numerous errors in specs, and some of the descriptions are not very accurate. This is not a criticism of Wes Barris, who runs the site himself. He's at the mercy of his contributors, who have varying levels of expertise, and no one person can critique all the info on the site. I've found Wes to be very accepting of suggested modifications over the years when I found something out of line.
...while not intending to anticipate the answer; at "http://steamlocomotive.com/allegheny/?page=co"
the same value occurs (Minimum weight per yard of rail on which locomotive could run):
C&O H-8 - 1644 140 lb rail
C&O H-8 - 1600 141 lb rail
You will find corresponding minimum rail weights for almost every type at steamlocomotive.com,
but no explanation is given, how they calculated it or which source these data come from, unfortunately.
John,
Where did you find the minimum rail weight requirement? This is a new one to me. Tie condition and spacing are usually considered more important than rail weight alone. According to track charts, C&O had 131RE and 132RE in general use on its main line in 1963. No 140-lb in sight.
...but why they get heavier during construction? I think LIMA knew how much all parts will weight.
Was LIMA let them built overweighted first and then being blamed later?
Did their weight lead to restrictions on their use at the C&O or Virg.?
Lars--
I checked the articulated pages at www.steamlocomotive.com
C&O had a weight limit of 726,000 pounds. Lima and C&O's contract agreement was for an engine weight slightly less than that. During construction, the weight ballooned to allegedly as much as 778,000 pounds, and Lima later paid C&O a monetary penalty for the overweight engines.
The H-8 required 141 pound per yard rail. The N&W A class required 120.4 pound per yard rail--so it could run in many more places than the H-8 would be able to run.
UP 4-12-2--but it was never utilized by the C&O to its full potential.
I believe the true is, that they did all their jobs with ease while still having reserves. Using a steam locomotive without excessive firing rates is a nice way, saving fuel and keep nice efficiency levels.
UP 4-12-2"Adding to this rivalry is the fact that Lima built the 2-6-6-6 in 1941 more to "outperform the N&W A" than to meet the C&O's true traffic needs.
--why should they use the "A" as a reference, when they built with the T1 2-10-4 a very powerful locomotive 12 years ago already. The Allegheny with its high factor of adhesion was certainly a better engine for the mountains, than the "A", too.
UP 4-12-2And the Allegheny achieved its size and power at the expense of having the heaviest axle-loading of any steam locomotive ever built, which severely limited it to operating only on the very best constructed main lines.
Can somebody enlighten us what went wrong with building process and they were blamed being overweighted?
I think the builder (LIMA) could draw exact theoretical weights matching final weights.
Did someone dictated design rules that were not really necessary, making some parts of the locomotive heavier than they really need to be?
-I mean, before reweighting, did ever somebody noticed their overweight or did running problems occur ? The C&O a had a strong track plant anyway...
Cheers
Thanks for typing out the Boyd quote. As expected, he was just reporting that "The consensus [among railfan writers] seems to be ..." -- which is true enough. Much of Le Massena's article has indeed become the conventional wisdom among railfans.
After reading the above post I was able to find a couple of reference websites that the other posters on this thread might find of meaning within the context of this discussion:
First is: http://crestlineprr.com/duplexexperimentals.html
"Welcome to the Crestline PRR Engine Facility
The Duplex and Experimental Steam Engines of the PRR: The Crestline Connection"
FTA:"...What makes the Crestline Engine Facility such a special place? The reasons are many, among them is its geographical location, and therefore home to experimental and production duplex steam engines. Crestline is the eastern most division point facility between Pittsburgh and Chicago on the Ft. Wayne mainline. To the east are the foothills of the Appalachian Mountains. To the west are the flat lands of the midwestern plains..."
Second is this website:
http://findarticles.com/p/articles/mi_qa3943/is_200505/ai_n13642634/?tag=content;col1
FTA: "...A quick glance indicates that the C&O J3s and the PRRT1 were fairly similar with respect to engine weight, weight on drivers, grate area and engine tractive effort. A closer look, however, reveals a substantial difference in total tractive effort because the C&O J3s were equipped with boosters.
Description of tests
PRR 5511 was the first T1 loaned to the C&O for the test program, and received its initial assignment at Huntington, W. Va., on September 4, 1946. Before completion of the test runs, PRR recalled the locomotive on September 7, 1946, and replaced it with 5539 on September 11, 1946. T1 No. 5539 left C&O after a final run to Cincinnati on September 14, 1946..."
THis last website's article stretches to about 15 or so pages and is well researched and referenced at the end. It provides an unusually detailed description of the comparison tests of C&ORR operating conditions when tested with the PRR T-1 locomotive. It should prove of interest here.
If I may draw any conclusion from all the sources I've read, it's that, in general, the flatland or relatively flat areas of the U.S. were dieselized first--resulting in the early elimination of fine "state-of-the-art" steam power on many roads. Where steam survived "late" it seems to have been generally in the mountains, especially in pusher service where speed was not the priority as much as tonnage.
That's partly why the magnificent challengers of Western Pacific and Rio Grande were gone early (also inferior wartime steel boilers in the case of Rio Grande), yet the older 2-8-8-2's slogged it out longer in the mountains.
And again, if the PRR had bought its own version of the N&W J (possibly slighter higher driver diameter) or the NYC Niagra (The SP G-4 would have not met clearance restrictions), it would have done everything the T-1 did on the Broadway, Spirit of St. Louis, Tralblazer, Jeffersonian, and Red Arrow and still done a fine job in NY&LB commuter service, without any double heading. Incidentally, double-headed K-4's did often substitue for T-1's on the Broadway.
I don't claim to be a motive power expert. But it is clear that the Santa Fe, SP, N&W, NYC, UP, and the NKP, among others, had motive power design teams more in tune with the actual needs of the operating department than either the PRR (steam and diesel) or the C&O. I cannot fault the PRR with regard to electric power however. No one can complain about the GG-1, the B-1 Switcher , or the MP-54 mu car. The early PRR diesel purchases showed their Philadelphia loyalty to Baldwin. OK for switchers, but the road power was a big mistake, particularly since it could not mu with other diesels.
You might object that the Central never did use Niagras in commuter service after they were bumped from premium trains. Hudsons rarely. First, Boston suburban service, the largest suburban NYC user of steam power, was among the first services to be dieselized, as part of total deiselization of the B&A. Even the Highland Branch got diesels before it was turned over to the MTA for light rail. Second, most NYC suburban services that used steam power did use head-end lighting power, like the C&NW, Erie, and CNJ did. The PRR had pretty much stayed with axle-driven generators and large batteries on its P-70's, which were the NY&LB passenger stock, not the P-54's. The Central did not wish to equip Hudsons (a few were equipped and used out of NWP and Harmon) and Niagras with oversized generators. Hudsons, like K-4's on the PRR did occasionally show up on peddler freights, showing the flexiblity of a well-design passenger locomotive. I do not recall any NYC suburban steam trains sufficiently long as to require double heading with Pacifics or Hudsons (or 4-6-0's on the Putnam for that matter!).
timz UP 4-12-2Jim Boyd in The Steam Locomotive, page 136, clearly states that Lima designed the C&O 2-6-6-6 to outperform the N&W A rather than to meet C&O's true traffic needs. What did he actually say? I'm guessing he didn't actually claim to know anything about it-- he just offered a surmise, or quoted somebody else's surmise?
UP 4-12-2Jim Boyd in The Steam Locomotive, page 136, clearly states that Lima designed the C&O 2-6-6-6 to outperform the N&W A rather than to meet C&O's true traffic needs.
timz-
Well, no bibliography was given. Jim Boyd states in the front that the "hundreds of books" consulted for this project were far too numerous to mention.
After a comment that entire books were written that compare N&W 1218 to the 2-6-6-6, Jim Boyd stated the following on page 136:
"Adding to this rivalry is the fact that Lima built the 2-6-6-6 in 1941 more to "outperform the N&W A" than to meet the C&O's true traffic needs. The consensus seems to be that "Lima's Finest" did, indeed, have the potential to outperform the A--and nearly every other steam locomotive ever built, for that matter--but it was never utilized by the C&O to its full potential. And the Allegheny achieved its size and power at the expense of having the heaviest axle-loading of any steam locomotive ever built, which severely limited it to operating only on the very best constructed main lines. The N&W A, however, worked to its last days doing precisely the job for which it had been so well designed."
Again--no sources were specifically mentioned by name.
HarveyK400GP40-2HarveyK400You're ignoring the elephant in the room that the double-headed K4s took 2 engine crews. Am I? It would be much more economical to pay 2 crews to run 2 paid-off K4s in this type of service that they excel at, rather than invest millions in a modern end-of-steam design. Especially when it was literally the end of steam. HarveyK400I would have gone with the T-1 if clearances and axle loads were acceptable. Why? As feltonhill pointed out, the T1's were all wrong for this service. I just don't understand from a railroad point of view why you expect to use a locomotive designed for sustained 80-100 mph service, in stop-and-go operation.
GP40-2HarveyK400You're ignoring the elephant in the room that the double-headed K4s took 2 engine crews. Am I? It would be much more economical to pay 2 crews to run 2 paid-off K4s in this type of service that they excel at, rather than invest millions in a modern end-of-steam design. Especially when it was literally the end of steam. HarveyK400I would have gone with the T-1 if clearances and axle loads were acceptable. Why? As feltonhill pointed out, the T1's were all wrong for this service. I just don't understand from a railroad point of view why you expect to use a locomotive designed for sustained 80-100 mph service, in stop-and-go operation.
HarveyK400You're ignoring the elephant in the room that the double-headed K4s took 2 engine crews.
You're ignoring the elephant in the room that the double-headed K4s took 2 engine crews.
Am I? It would be much more economical to pay 2 crews to run 2 paid-off K4s in this type of service that they excel at, rather than invest millions in a modern end-of-steam design. Especially when it was literally the end of steam.
HarveyK400I would have gone with the T-1 if clearances and axle loads were acceptable.
Why? As feltonhill pointed out, the T1's were all wrong for this service. I just don't understand from a railroad point of view why you expect to use a locomotive designed for sustained 80-100 mph service, in stop-and-go operation.
I don't know the piston stroke or boiler pressure for either the K-4 or T-1; but both had 80" drivers and capable of 100 mph by recorded accounts. Whether only one was designed for sustained high speeds instead of stop-and-go operation seems to be splitting hairs or taking a comment out of context. The ability to produce steam would be crucial in either event, with little time to hook up, run more efficiently on expansion and recover boiler pressure other than while braking and dwelling at a stop. Both types of locomotive were capable of 60 mph or more between stations on the NY&LB; but with different size trains. This would be more than adequate to compete with driving.
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