All the references to the 'Big Boy' 'improvement' i have seen, including the drawings, have referenced Chapelon. I don't have my copy of Carpenter's translation but I don't believe the improvement project is in there; the original LLAV in French was published in 1938 and only sporadically updated postwar. I had the impression Chapelon was peddling the idea both of his 2-10-4 and some other improvements to America before the great die-off around 1947, and did the Big Boy more as a sort of 'teaser' about what American and French approaches could accomplish if fused than an actual 'design proposal'.
However, if any road could have benefited from the revised locomotive postwar (e.g. under real operating conditions, not wartime as benefited the PRR Q2s) it would have been UP, which would infamously go on to run trains with as many as 17 first-generation diesels -- all running -- and use a number of comparably high-horsepower consists while fuel prices permitted.
Much of the 'proper procedure' for firing the subbituminous fuel is probably undocumented today except by accident of preservation. I know of nothing like the Reading or NYC firing courses adapted to civer that fuel. What I suspect was one issue would be if the fireman allowed thin spots or holes in the grate, letting primary air into the firebox volume, when the engine had to be worked at long cutoff with high resulting draft. This would give conditions under which much of the stoked friable material would be levitated and ejected, going right through the firebox and chamber undissuaded by a Gaines wall or other flow disruption and quite likely without effective full ignition or 'flameholding' in the levitated plume length.
I have never read a reference that the ejecta from one of the engines in question was spectacularly reigniting upon exposure to atmosphere as at Sandoliang -- the many pictures just show 'burning-of-Rome-effects' black or brown smoke. (Of course I have not seen nighttime pictures of Jabelmann engines being worked hard...)
In my opinion correct firing of either a late Challenger or a Big Boy would involve very good attentive monitoring of the fire and prompt cleaning of dead spots and filling of thin ones, but also a certain amount of lifting of coal off the distribution table into the combustion plume at higher demand, a bit like mixed pulverized-coal firing. How easy the latter would be with the 'stock' stoker and jet controls, I don't know, and of course I have never tried it firsthand.
C&O was famous for tolerating exordinate axle load in its locomotives, but that wasn't the reason the Alleghenies were so heavy... or the issue with their being 'overweight'.
If you compare the detail design of the Allegheny to the earlier N&W A, you'll be struck by the way in which steam mass flow is arranged from the throttle to the four cylinders and then back out the exhaust, with the pipes to the rear engine clearing the hinged forward one, and of course the forward engine's pipes being both 'flexible' and varying in length. The Allegheny does this with good large-diameter pipe and fittings, carefully flow-shaped. As I recall, no holds were barred in getting flow optimized... and all that plumbing is where much of the weight comes from. Meanwhile the Nicholsons in the firebox add much of the weight of multiple water legs ... a major reason for wanting three carrying axles in the space Super-Power Berks only needed two.
The problem was not that the engines were too heavy for the track or economical operation; it was that the unions (as part of acceptance of large articulated locomotives) had insisted upon a wage scale tied to the locomotive weight. Lima found it expedient to fib to C&O (and I think to Virginian) about the weight and, mirabile dictu, C&O somehow didn't weigh their purchases to confirm this right away. At least one author indicated that the additional wages abd settlement costs when this came to light wiped away much of the 'added profitability' the Alleghenies offered over the T-class engines...
Incidentally, Withuhn appears to be echoing Mr. Bruce in saying Alco 'invented' the idea of removing vertical hinging on the forward engine and accommodating vertical curvature entirely in the equalization. The A was designed for high speed, and uses this feature implicitly to achieve running stability.
railracer Thanks for your input SD70dude. I think I also remember reading somewhere that Big Boys produced all the steam needed, so I agree they probably wouldn't have produced more power. I am just curious how much less coal they could have used to produce that HP. More of a hypothetical question, as it would have been impractical to bring in coal from elsewhere. I'm sure that question has been answered somewhere as well. Thanks again!
Thanks for your input SD70dude.
I think I also remember reading somewhere that Big Boys produced all the steam needed, so I agree they probably wouldn't have produced more power. I am just curious how much less coal they could have used to produce that HP. More of a hypothetical question, as it would have been impractical to bring in coal from elsewhere. I'm sure that question has been answered somewhere as well.
Thanks again!
There is that notorious Trains Magazine article "Big Boy -- Big Mistake?" claiming that the Big Boy and other "Super Power" steam locomotives were misapplied in service (Super Power was a Lima slogan for their 2 and 3-axle trailing truck locomotives with outsized fire grate area whereas the Big Boy was an ALCo product).
Bill Withuhn's posthumously published "American Steam Locomotive" lays out a case why the Big Boy should be considered a great success. The concept was to have enough tractive effort to take a 4000-ton train up the Wasatch Grade eastward from Ogden, Utah without a helper and have high enough drivers and enough boiler capacity to "run with that train" across Wyoming. It was combining these conflicting requirements along with the ability to use a locally source low-BTU coal into a single locomotive that lead to the unique 4-8-8-4 wheel arrangment along with its driver size. It also incorporated design concepts of the articulation hinge and front boiler support developed on the 2nd Challenger order for smooth high-speed operation. Withuhn chronicles the engineering tradeoffs in its design.
The 2-6-6-6 Allegheny (a Lima product for C&O and later Virginian) was successful enough, and more were built than the Big Boy, but Withuhn agrees with the Trains article that this locomotive was based more on "beating the Norfolk and Western 2-6-6-4 A-class" rather than the same sort of rational design of the locomotive for its service requirements as done by Union Pacific teamed with ALCo on the Big Boy.
The Allegheny was supplied a high-BTU Eastern coal and produced a record level of horsepower that was not achieved at its speed and tonnage rating in actual service, but giving it that high horsepower rating and fewer drivers than the Big Boy made it overweight for its total number of wheels, resulting in a record high axle load. Can't call it a failure because apart from suing Lima into losing money on this locomotive type, I guess the C&O had heavy enough rail to take the axle load.
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
railracer Overmod and Paul, I think the questions of what design changes could have been made to use subbituminous more effectively and also what mistakes a fireman could make to get into a bad situation are very interesting. I know next to nothing about locomotive firing. Are there any resources that describe "proper firing techniques" for subituminous coal? Does anyone know if UP did any formal training for its firemen?It sounds like Chapelon or Porta had ideas on different designs. Are they referenced in books? Thanks all
Overmod and Paul,
I think the questions of what design changes could have been made to use subbituminous more effectively and also what mistakes a fireman could make to get into a bad situation are very interesting. I know next to nothing about locomotive firing. Are there any resources that describe "proper firing techniques" for subituminous coal? Does anyone know if UP did any formal training for its firemen?It sounds like Chapelon or Porta had ideas on different designs. Are they referenced in books?
Thanks all
Chapelon wrote "La Locomotive a Vapeur" (The Steam Locomotive) -- hard to get, never read it, Amazon seems to have used copies
La Locomotive a Vapeur: English Edition: Chapelon, Andre, Carpenter, George: 9780953652303: Amazon.com: Books
that are still pricey, I cannot tell if this is in the original French or is an English-language translation.
Wardale's "The Red Devil and Other Tales of the Age of Steam" lays out Porta's ideas. I read it when I was able to order its reprinting a few years back -- it is even more expensive on Amazon.
The Red Devil and Other Tales from the Age of Steam: Wardale, David: 9781909358010: Amazon.com: Books
The Coalition for Sustainable Rail "white papers" has interesting essays on Porta's ideas White Paper Program — Coalition for Sustainable Rail (csrail.org)
The Advanced Steam Traction Trust is a spinoff of Wardales abandoned 5AT project for a new-design steam locomotive for steam-enthusiast "fan trips" Advanced Steam Traction | Steaming into the Future (advanced-steam.org) -- they have information and pamphlets and books for sale.
All I can say is WOW! Talk about wasted fuel...
Thanks for sharing.
Flintlock76Crappy coal going up the stack? The Chinese could tell you all about it. https://www.youtube.com/watch?v=Ampco2JqSc8
https://www.youtube.com/watch?v=Ampco2JqSc8
A illuminating video.
Never too old to have a happy childhood!
You sure it wasn't L. D. Porta rather than his mentor A. Chapelon making that claim?
Chapelon visited the US, observed US designs and commented on their mechanical robustness -- I don't think he was "in" to expressing his desire to improve them, but Mr. Porta didn't have that social inhibition.
The other thing about using the low BTU coal more effectively, the grandparent post quoted a source that it was possible to get into a situation where one was firing them very ineffectively. It is worth learning more about what went wrong to blow a tender load of that coal up the stack in short order, although I am sure the locomotive was photogenic by US railfan standards when that happened?
SD70DudeThe question of how much better a Big Boy would have been with with better quality coal has been asked before.
A far better question in my opinion would be ways to improve operation using the subbituminous "more effectively". As noted that would involve better firing practices, but a wide variety of other changes including many of Chapelon's would improve things without hypothetically involving changing to different and at least ultimately higher-cost fuels.
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.
UP burned the poor-quality coal because it was dirt cheap and easily available in Wyoming, being produced in local mines (the same applies to the Rosebud coal that spurred Northern Pacific to build the first 4-8-4s). So while better coal likely would have resulted in less smoke and increased range UP's overall fuel costs probably would have gone up if they switched.
UP had coaling towers at strategic locations along their mainline, like many railroads, and refuellings would have been planned into the daily operation of trains. They would probably have to stop at many of those same locations anyway to take water.
Greetings from Alberta
-an Articulate Malcontent
Crappy coal going up the stack? The Chinese could tell you all about it.
Thanks Overmod for the reply.
I will see if I can lay my hands on a copy of Huddleston's book. Sounds interesting.
Your theory certainly seems plausible based on the amount of unburned coal that the late Challengers and Big Boys put out their stacks! After digging in a bit further Kratville's book also gives some numbers that seem to back that up.
The Fetter Challengers had 108 sq. ft grates with a Gaines arch 5'9" in front of the thoat sheet and a combustion chamber extending 86" forward of the throat sheet. Quite a bit of volume to burn up that levitated coal.
The Jabelmann Challengers had roughly 132 sq. ft grates and combustion chambers extending 106" forward of the throat sheet. I'm assuming the thought was the bigger grate would lessen the draft per square foot and allow more dwell time to burn the coal. However with that big MB stoker was throwing a lot of coal on the grate and plus the fines in the air, I could see where that would overwhelm the combustion area. One can only wonder how much more efficient the Big Challengers and Big Boys would have been with some better coal?
Thanks again for the insight!
You might want to find a copy of Eugene Huddleston's book where he compares the Fetter Challenger design to the N&W A.
One of the official pravdas out there is the idea that Fetter and Alco started with the general Nine idea, hinging the six-axle wheelbase in the middle while retaining the four-wheel lead truck, and going to four outside cylinders without need for derived motion. The four-wheel truck in the rear is only for weight bearing and distribution, and could as easily have been two-wheel, decidedly unlike the situation on deep-firebox engines like the N&W A or the Allegheny.
My interpretation of the firing issue would be commonalty with the observed Big Boy phenomenon of levitation of the crappy subbituminous coal fuel at high draft. This results in somewhat oil-firing style plume and heat release, as the part of the stoked feed that levitates is carbureted and ignited much as liquid fuel would be. However, the ability of the radiant-section uptake or the convection section to actually use this mass of fuel might be insufficient... meaning you get towering clouds of unburned fuel in the exhaust and a rapidly emptying tender.
Hello,
I've been reading Kratville's book on the Challenger Locomotives. An interesting read, at least for me, as I didn't really know much about about the CSA-1 and 2 series.
One comment from Kratville really intrigued me. On P. 144 he states "One peculiarity of the big Challengers however was there enormous coal appetite if not operated properly. If a crew did not use proper firing or the locomotive was not in fairly good working condition, a 3900 would go through a tenderful of Rock Springs coal in a hurry! The earlier design did not have this problem..."
I've have also seen in one of the video interviews with former crewmen that 3900s were not particularly easier to fire and if one made a mistake, is was not easy to recover.
I wondered if anyone had any thoughts about what made the 3800s more forgiving??
Thanks for any input!
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