...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.
lars
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.
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 ).
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.
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 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
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
-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 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
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.
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 ;-)
GP40-2the Yellowstone Class was the ultimate all around heavy freight steam locomotive
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.
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
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
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?
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
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?
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
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
GP40-2I wouldn't consider the Big Boy scaled up at all
that is, why they were called the boys... big to attempt, but not grown up enough, yet...
young and wild ;-)
A last thought on the idea of a T-1 on the NY&LB. Just possibly the turntable at South Amboy just wasn't long enough? At Bay Head there was a loop and complete trains were turned.
locobasede 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 LlansoLocobasedelocobase@comcast.net
Thank you Steve, for reply. Now, were those figures updated? Or where they specific to their own RR's?
Lars LocoSurprisingly, those "smallest" Yellowstone's were even were longer than the " big"M3/M4...
GP40-2My theory is that after the B&O's new diesel request was turned down, they used their political clout with the War Department (after all, Washington D.C. was their backyard) to get the EM1 design approved for production.
-interesting and plausible theory.
The years stood yet not still, and with a late 2-8-8-4 design the B&O take much of it as an advantage,
which seemed to have been paid out.
-The doom for UP-engines was, all the 800, 3900 and 4000 class was, at the end of WW2, accumulated running and maint. cost. was quite a percantage ( 3/4 or so ) of their whole purchasing costs... running those 4000 class especially, though they moved quite some tons.
They had the facility anyway ( mostly Cheyenne ), but after steam disappeared, I can tell exactly what happened with the RR-Town...
...1963, there was little left of it ;-)
-I very appreciate, that your nice Big Country still give nice reserve places for Big Engines...
Lars--
Yes, as I had said my figures come from The Challenger Locomotive book.
I don't have the Big Boy book. Ok, given the average figures you quoted, I'll buy the 3600 "average".
Regarding the contention that the Big Boy is really just a Yellowstone--I just cannot agree. From Kratville's writings which I have read, I do not recall any mention of UP having looked at the 2-8-8-4, but instead that they were interested in scaling up their own challenger.
In the history supplied with the new Athearn Genesis Big Boy model, it specifically states that "the easiest solution was to scale up the successful Challenger design by adding another pair of drivers to each half of the locomotive making a 4-8-8-4 design. The task before Jabelmann's department was to fit such a large machine into the real world." Athearn's history makes no mention of the 2-8-8-4's.
The Union Pacific often did things "their own way"--often disagreeing with and sometimes even outright ignoring ALCO's recommendations because they considered ALCO's position to be a rather "conservative" design philosophy. Case in point: Alco specifically stated the 4-12-2 was not designed for/should not be used at speeds above 35 mph. Union Pacific had absolutely no intention of running them that slow--but instead in the 40 to 60 mph range--and sometimes faster than that. Also--Alco wanted the middle blind drivers on the 4-12-2's, and 9000 was delivered with at least one set blind (no flanges)--but even before release for operation, UP replaced the wheelset with normal flanged wheels.
It (the Big Boy) may appear similar to a Yellowstone, but I think UP was doing "their own thing" without having an eye on what NP/DM&IR were doing. Even in the mid-1930's, UP and NP had different design approaches on the original Challengers--that is well documented--the NP Challenger may look generally like an early UP Challenger, but they were different animals. NP's version had significantly higher starting tractive effort.
John,
Maybe they have done it unintended.
Do not know, how much they shared common avail. design parts or particular designs, buts lets say, all starts with some ( GSI - mostly ? ) casted frame, scaled up on a wished/designed/-frame...I mean the technical approach of such an engine. OK. you are right to say they were an equivalent stronger ( yet more expensive ) articulated than the Challengers in gen. UP service. But from outside they look more like a Yellowstone to me... ---do i feel wrong?
-BTW. agree too that the team around Jabelman and Alco and more worked pretty hand in hand together as they have been ordered to...
UP 4-12-2 It (the Big Boy) may appear similar to a Yellowstone, but I think UP was doing "their own thing" without having an eye on what NP/DM&IR were doing. Even in the mid-1930's, UP and NP had different design approaches on the original Challengers--that is well documented--the NP Challenger may look generally like an early UP Challenger, but they were different animals. NP's version had significantly higher starting tractive effort. John
Perhaps generally "in the same class"--BUT
NOT in the same class as compared to one particular road's SD40-2 versus all other SD40-2 variants, or one road's FT versus the others.
Back to lack of T-1's on the NY&LB. Thought comes the PRR already had a locomotive that could have avoided double heading: the M-1 Moutain 4-8-2. Would not it have adequate for the NY&LB commuter trains? But possibly too long for the South Amboy turntable? And the use of M-1 probably meant the PRR saw no reason for a 4-8-4 pre-WWII. But just what was the thinking that led to the S-1? Did they really plan on a system-wide infrastructure modification to be able to use this locomotive?
daveklepperBack to lack of T-1's on the NY&LB. Thought comes the PRR already had a locomotive that could have avoided double heading: the M-1 Moutain 4-8-2. Would not it have adequate for the NY&LB commuter trains? But possibly too long for the South Amboy turntable? And the use of M-1 probably meant the PRR saw no reason for a 4-8-4 pre-WWII. But just what was the thinking that led to the S-1? Did they really plan on a system-wide infrastructure modification to be able to use this locomotive?
Interesting question about using M-1s on the NY&LB - certainly better than a single K-4 and about as good overall as the T-1. On the plus side, the M-1 had 72" drivers and simpler machinery. Other than the boiler pressure and grate area, was there much difference in heating surfaces between the two types?
As an earlier post pointed out though, turning engines may have been an issue, even with the original short tender. Anybody got anything specific?
I agree--what were they smoking when they were designing such long locomotives?
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