SD70Dude One must keep in mind that UP ordered the Big Boys with the intent of acquiring locomotives that could haul what was then a normal tonnage train up their grades without a helper (or a much heavier train with a helper), and then run those same trains at 50+ mph on flatter track. They proved very successful in doing so with the coal they were given. And even if we assume that a Big Boy would have developed significantly more power with better coal that does not mean that the resulting 'super-duper power' locomotive would have fit into UP's operation any better than the existing locomotives did. In a lot of cases running freight at 70+ mph isn't really much better than 40 or 50, you just burn a bunch more fuel (or more expensive fuel) and get to your stops a few minutes sooner, and there were a lot of those in the steam era (even if you coaled less frequently you would still have to stop for water, unless you used much larger tenders or 'canteens', which I don't believe UP did). UP got exactly what they asked and paid for, and it worked out very well for them.
One must keep in mind that UP ordered the Big Boys with the intent of acquiring locomotives that could haul what was then a normal tonnage train up their grades without a helper (or a much heavier train with a helper), and then run those same trains at 50+ mph on flatter track.
They proved very successful in doing so with the coal they were given. And even if we assume that a Big Boy would have developed significantly more power with better coal that does not mean that the resulting 'super-duper power' locomotive would have fit into UP's operation any better than the existing locomotives did. In a lot of cases running freight at 70+ mph isn't really much better than 40 or 50, you just burn a bunch more fuel (or more expensive fuel) and get to your stops a few minutes sooner, and there were a lot of those in the steam era (even if you coaled less frequently you would still have to stop for water, unless you used much larger tenders or 'canteens', which I don't believe UP did).
UP got exactly what they asked and paid for, and it worked out very well for them.
Well put.
sgriggs SD70Dude The question of how much better a Big Boy would have been with with better quality coal has been asked before. I recall reading in the magazine a few years ago about how during testing it was found that the boiler could fully supply the demands of the machinery, so I suspect they and the Challengers wouldn't make much if any more power on better coal. I think that article was written by Ed King ("Big Boy versus Allegheny") and appeared in Trains magazine. Here is the quote: "Union Pacific historians are fond of saying that the Big Boy could have produced even more than its 6300 drawbar horsepower (dbhp) if it hadn’t had to use low-quality coal. But that’s difficult to understand, given that during its tests the Big Boy was operated at full capacity and the boiler was fully supplying the demands of the machinery. If higher quality fuel had been used, it might have been able to use less of it." I'm not sure I agree with Mr. King's statement, and I don't understand how he could say the boiler was fully supplying the demands of the machinery. The demands of the machinery are a function of cylinder volume, valve dimensions, speed, and valve cutoff. So maybe the boiler was able to maintain 300 psi while supplying the demands of the machinery at the speed and cutoff used in the test, but who is to say that the machinery couldn't have produced higher horsepower if the cutoff had been increased? Comparisons with other large high horsepower locomotives are helpful here, and I will use the C&O H8 and the PRR Q2 because we have some test data for each. The cylinder volume of the Big Boys wasn't the limitation as they had larger cylinders than either the C&O H8 or the PRR Q2. There is pretty strong evidence that valve dimensions weren't the limitation, as the FEF-1 (UP 800 class) locomotives used the same sized 12" piston valves with 7" stroke, and they produced 4870 IHP/3700 DBHP on test from just two cylinders. I have never seen any detailed cutoff information for either the C&O H8 or the Big Boy tests, but the PRR Q2 Altoona test report shows it produced its maximum drawbar horsepower at a whopping 47% cutoff (7016 DBHP @ 49MPH). Of course, a railroad's objective is not to peg the horsepower meter (it was certainly not the economical way to run a railroad during the steam era), but I think Mr. King dismissed the coal quality concern a bit carelessly.
SD70Dude The question of how much better a Big Boy would have been with with better quality coal has been asked before. I recall reading in the magazine a few years ago about how during testing it was found that the boiler could fully supply the demands of the machinery, so I suspect they and the Challengers wouldn't make much if any more power on better coal.
The question of how much better a Big Boy would have been with with better quality coal has been asked before. I recall reading in the magazine a few years ago about how during testing it was found that the boiler could fully supply the demands of the machinery, so I suspect they and the Challengers wouldn't make much if any more power on better coal.
I think that article was written by Ed King ("Big Boy versus Allegheny") and appeared in Trains magazine. Here is the quote:
"Union Pacific historians are fond of saying that the Big Boy could have produced even more than its 6300 drawbar horsepower (dbhp) if it hadn’t had to use low-quality coal. But that’s difficult to understand, given that during its tests the Big Boy was operated at full capacity and the boiler was fully supplying the demands of the machinery. If higher quality fuel had been used, it might have been able to use less of it."
I'm not sure I agree with Mr. King's statement, and I don't understand how he could say the boiler was fully supplying the demands of the machinery. The demands of the machinery are a function of cylinder volume, valve dimensions, speed, and valve cutoff. So maybe the boiler was able to maintain 300 psi while supplying the demands of the machinery at the speed and cutoff used in the test, but who is to say that the machinery couldn't have produced higher horsepower if the cutoff had been increased? Comparisons with other large high horsepower locomotives are helpful here, and I will use the C&O H8 and the PRR Q2 because we have some test data for each. The cylinder volume of the Big Boys wasn't the limitation as they had larger cylinders than either the C&O H8 or the PRR Q2. There is pretty strong evidence that valve dimensions weren't the limitation, as the FEF-1 (UP 800 class) locomotives used the same sized 12" piston valves with 7" stroke, and they produced 4870 IHP/3700 DBHP on test from just two cylinders. I have never seen any detailed cutoff information for either the C&O H8 or the Big Boy tests, but the PRR Q2 Altoona test report shows it produced its maximum drawbar horsepower at a whopping 47% cutoff (7016 DBHP @ 49MPH).
Of course, a railroad's objective is not to peg the horsepower meter (it was certainly not the economical way to run a railroad during the steam era), but I think Mr. King dismissed the coal quality concern a bit carelessly.
Greetings from Alberta
-an Articulate Malcontent
The thought of an A blasting up Blue Ridge at 50 mph with 40 passenger cars on the tank is quite the mental image. Just amazing, actually! I sure would have liked to see how David P. Morgan would have described such a Herculean perfromance!
My image is more like the box car type of troop cars that I think Pullman made for the military.
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BigJim railracer That led to another question for me though and that was why weren’t the 3900’s “free steamers.” Watching videos of N&W steam, it is not uncommon to see an "A" or "Y6" lifting a pop while lugging up the Blue Ridge. And, one of my former mentors told me how when on a 40 car troop train he had his "A" lifting the pops at 50mph going up Blue Ridge. His engineer told him "If you can do that son, you'll be all right!"
railracer That led to another question for me though and that was why weren’t the 3900’s “free steamers.”
Watching videos of N&W steam, it is not uncommon to see an "A" or "Y6" lifting a pop while lugging up the Blue Ridge. And, one of my former mentors told me how when on a 40 car troop train he had his "A" lifting the pops at 50mph going up Blue Ridge. His engineer told him "If you can do that son, you'll be all right!"
BigJimit is not uncommon to see an "A" or "Y6" lifting a pop while lugging up the Blue Ridge.
It might have been interesting to see how the 'Clinchfield Challenger' would have performed if still coal-burning at the time...
railracerThat led to another question for me though and that was why weren’t the 3900’s “free steamers.”
railracer SD70Dude I'm really enjoying this discussion on how thermodynamics applies to steam locomotives. It stands in stark contrast to the 'training' programs of many railroads during the steam era, where a new Fireman would write a basic rules and theory exam, make as few as three student trips, and then start working regularly. They learned on the fly, some 'got it' and some didn't. The same is true for Engineers, some guys never learned how to run a locomotive efficiently, and others delighted in making the Fireman's life far more difficult than necessary. To help further my understanding, I searched the Union Pacific Historical Society website for any documents they might have regarding fireman training for UP. I didn’t find any (although they may exist) but I did come across an article titled “Fireman” written by Ernest S. Peyton in a back copy of Streamliner magazine. It detailed some experiences he had with both 3900 and 4000 class engines. He worked with an engineer a couple times that ran with very high back pressure which I’m guessing was a consequence of putting the Johnson bar “in the corner” and leaving it there. While the 4018 apparently was able to handle the strain, another trip on the 3933 with the same engineer was a nightmare for Ernie Peyton. He stated that with the high draft he could see the fire lifting of the grates and soon he had holes in the fire, which he was desperately trying to fill with coal. He noted that the 3900s we not “ free steamers” and he was soon seeing the psi falling and getting low on water, because he dare not leave the injector on too long. This sounds a lot like the scenarios laid out here by several about how getting “behind” with steam would lead to poor fuel economy for a variety of reasons, especially if the fireman was relatively inexperienced or just not very good at it and the role the engineer played. That led to another question for me though and that was why weren’t the 3900’s “free steamers.” I compared the combined evaporative and superheating surface between the CSA-1 and 2 series with the Jabelmann Challengers and they were relatively the same(7, 031 sq ft for the early and 6957 sq. ft for the late Challengers) only about 2% difference. However, when comparing the evaporative surface only, the early series has 5,381 sq. ft and the late series only 4,795 sq. ft, about 11% less. It seems that Alco and UP were counting a lot on the higher PSI and more superheating surface to get more out of each pound of steam. Not a bad thought as long as the engineer understood that and was willing to adjust the cut-off to get the most out of engine design? Speculation on my part, of course. Were there other reasons late Challengers were not considered to steam freely? Thanks to all who have contributed thus far, it has really helped me understand things better.
SD70Dude I'm really enjoying this discussion on how thermodynamics applies to steam locomotives. It stands in stark contrast to the 'training' programs of many railroads during the steam era, where a new Fireman would write a basic rules and theory exam, make as few as three student trips, and then start working regularly. They learned on the fly, some 'got it' and some didn't. The same is true for Engineers, some guys never learned how to run a locomotive efficiently, and others delighted in making the Fireman's life far more difficult than necessary.
I'm really enjoying this discussion on how thermodynamics applies to steam locomotives.
It stands in stark contrast to the 'training' programs of many railroads during the steam era, where a new Fireman would write a basic rules and theory exam, make as few as three student trips, and then start working regularly.
They learned on the fly, some 'got it' and some didn't. The same is true for Engineers, some guys never learned how to run a locomotive efficiently, and others delighted in making the Fireman's life far more difficult than necessary.
Thanks to all who have contributed thus far, it has really helped me understand things better.
PM me for the boring details.
The book is quite interesting. I would give my two cents whenever I would be free.
railracer timz railracer By the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys. Main line freight crews were never assigned that way, were they? "I'm up next, but I don't want that steamer -- I'll use my seniority to wait for a diesel." Hi Timz Not sure how train crews were dispatched, but comment was speculation based on some comments from the "Last of the Giants" volume III and how steam was being used on the UP beginning in the early 50's. A retired machinist stated working with the diesels was preferred and since he had less senority he was assigned to the steam locomotive backshop, versus working with diesels. I also read a very interesting article by Mark Amfahr on Big Boy operations stating that by the early to mid fifties UPs policy was to only use steam when diesels weren't available. Also they were only to be used on drags and other non-priority freight so that large trains could be accumaulated to get the most economy out of the 4000s and 3900s. In effect they had become " secondary" or surge power. I was just speculating that the more senior crews would have been used for the regular manifest and priority freights and crews with less seniority would be called up when conditions justified reactivating steam. I could be completely wrong however.
timz railracer By the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys. Main line freight crews were never assigned that way, were they? "I'm up next, but I don't want that steamer -- I'll use my seniority to wait for a diesel."
railracer By the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys.
Main line freight crews were never assigned that way, were they? "I'm up next, but I don't want that steamer -- I'll use my seniority to wait for a diesel."
One would be amazed at the efforts people will go to in their attempts to secure the run they 'want' when working in a FI-FO pool.
Never too old to have a happy childhood!
[quote user="timz"]
Frankly, having seen the component layout of the Dickens-Barker burner and observed it in action, I see no difficulty in its developing sufficient heat release and plume formation for effective high-horsepower operation.
This was not a kludge like the 'industrial boiler' burner setup on RDG 2100, and inspection of the components will tell you so.
Of course, perhaps it is a great scam after all, with doctored photos and special effects like some claim NASA's moon shots used. I'm certainly not in a position to get the UP team to prove otherwise. But I could design a system that would work... and it would not look very different from what Dickens and Barker laid out.
Yes, it isn't exactly straining at its leash on these excursions.* We would want to impose typical 1944 loads on the same routes to see if it was able to perform close to what the records say was the case on those routes with those tonnages. Just burning oil, though...
*Or, it really is!
RTroy I'd heard for years that a BB couldn't run properly on oil - but clearly does.
railracerBy the 1950's many of the more senior engine crews were transitioning to diesels, which were the more desried jobs. This left the younger, less experienced crews to the Challengers and Big Boys.
The 1942 Railway Age article on UP's new 4-6+6-4s said they were designed for coal having 11800 BTUs per pound.
Sounds reasonable. PRB coal is a higher quality coal than lignite, but a lower quality than the Rock Springs coal. The NP went to PRB coal from Colstrip in the mid 1920's as the Red Lodge coal seams were getting expensive to work. The strip mines at Colstrip were much cheaper to work with the advent of large electric shovels and draglines.
Coal from the Roundup mines is of higher quality, but those mines were adjacent to the Milwaukee and would have involved a direct interchange at Miles City or indirect interchange via the GN's Mossmain to Great Falls line.
The last number I remember seeing for PRB coal-by-rail was 7550, and it was called 'subbituminous' in context.
timz You're thinking of NP. UP coal wasn't great, but it was better than poor. When the UP 4-6+6-4s were new, one article mentioned they were designed to burn 11000 BTU-per-pound coal, or maybe it said 11500 BTU/lb -- don't recall. Powder River coal is 9000 BTU/lb or less, isn't it?
You're thinking of NP. UP coal wasn't great, but it was better than poor. When the UP 4-6+6-4s were new, one article mentioned they were designed to burn 11000 BTU-per-pound coal, or maybe it said 11500 BTU/lb -- don't recall. Powder River coal is 9000 BTU/lb or less, isn't it?
IIRC, PRB coal is less than 9,000 BTU/lb and has to be kept wet to prevent spontanaous combustion. There are several places in the Powder River basin where coals seams caught fire in geologic time and turned the soil above into some sort of brick. OTOH, sulfur is not an issue.
SD70DudeUP burned the poor-quality coal because...
railracerUP also went from a lot of 4" flues ( 177) and few 2-1/4"tubes (45) in series 3 and 4 to a lot of tubes (177) and fewer flues( around 60?) in series 5. They also went back to the Type A superheater, so...
D&H Challengers, like their 4-8-4s, were bituminous-burning locomotives.
Anyway to compare with coal use on the Delaware & Hudson Challengers, burning anthracite?
There is an article somewhere on the UP steam site with detail pictures of the components of the Dickens-Barker burner. Austin described this as a 'modified Thomas burner' in West Chicago, but it is considerably more than that.
https://m.youtube.com/watch?v=Up1UaMVnv4M
An interesting characteristic is that the locomotive can hold nominal working pressure (necessary to work some of the auxiliaries properly) using only natural draft (no blower). That meant that the only time I saw the blower engaged was when the whistle had been enthusiastically blown (as enthusiastically as the West Chicago folks allowed, anyway, which was supposedly much less than Ed likes to do!) and even then it only needed cracking a small, virtually inaudible amount...
The arrangement and orientation of the tuyeres alone will tell you why this works so nicely.
(If I recall correctly (and this is largely second- or third-hand via Kratville) the late-'40s 'emergency' equipment involved two burners and a makeshift firepan, and was not reportedly successful although I don't remember learning any of the gruesome details.)
I'm curious about BB 4014, now running and burning oil. I'd heard for years that a BB couldn't run properly on oil - but clearly does. I've no expertise here at all, just wondering how UP and the steam shop designed the oil burning equipment to produce enough steam for the 4014.
On a semi related note, I find it a tiny bit ironic that 4012 (as I recall) sits in Steamtown in Scranton PA - in the heart of anthracite country. Yes, I know anthracite burns very differently then soft coal, so boilers are designed differently.
Yes, you are quite right.
Thanks for elaborating on those points!
railracerLots of plugging with water contaminants and burn out of the return bends.
There are many sources that talk about the maintenance issues with the type E on both the Challengers and Big Boys. Lots of plugging with water contaminants and burn out of the return bends. I seem to remember an article stating elements in the type A were a larger diameter therefore less susceptible to plugging and also were much simpler to maintain? An article written by Steve Lee mentions ( I can't remember the name of the article) the elements in the series 1 4000s Type Es were eventually shortened by 23" to reduce the issues with the return bends.
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