In the other thread a few guys mentioned Le Massena's famous article in June 1968 Trains that tried to rank the largest US steam locomotives, both by power and by merit. As he commented on the engines' merits he naturally included comments on the railroads operating those engines-- railroad A did a fine job, railroad B clearly was run by pointy-haired bosses. He calculated the "potential power" of each engine in arbitrary units: square feet of grate area times pounds per square inch of boiler pressure. A UP 4-8+8-4 had 150 square feet of grate and 300 psi, so its potential power was 45000, putting it in second place behind the NP 2-8+8-4, which (initially?) had 182 sq ft and 250 psi. Third place was one of those D&H experimental compound 2-8-0 from circa 1930, which had 82 sq ft and 500 psi. This raises a question, namely: Huh? Fortunately he explained. "Why select boiler pressure and grate area as measures of potential power? The reason is not difficult to comprehend. Going back to the high-school physics class..." Mark that. It's simple, he says-- no higher education required. In a couple sentences he's going to make a clanger of a mistake, which the reader will be baffled by: could he really have meant that? I must be misunderstanding him-- it must be more complicated. But it isn't. "...recall that power is defined as how much energy is released or developed in a specified time. For steam, this energy is expressed as volume multiplied by pressure. Hence, steam "power" is boiler pressure multiplied by the quantity produced per hour or minute." I'm not sure that's quite right, but close enough for us: power is pressure times volume of steam produced per unit time. "Now, since the quantity of steam is related closely to how much fuel is burned per square foot of grate area, the fuel aspect can be eliminated by saying that for equal fuel consumptions [per square foot of grate], the larger grate area will produce more steam per hour. Hence, it can be seen that a locomotive which has twice the grate area and twice the boiler pressure of another (both having properly proportioned fireboxes and boilers) has four times the potential power (twice the grate area and twice the boiler pressure) for equal fuel consumption per square foot of grate."
The mistake is in the first line of that quote-- "the quantity of steam" in that sentence means weight of steam, not volume. Two engines with the same grate area will produce about the same weight of steam per hour; if one has double the pressure, the volume of steam it produces per hour will be roughly half.
Some will ask: if it's true he made such an obvious error, why haven't the legions of razor-sharp railfan nitpickers mentioned it? Well, on page 41 he favorably compares the SFe 3460-class (412,000 lb "total weight") to an IC 4-6-4 (692,000 lb "total weight"). Presumably he didn't really think the IC had a 4-6-4 nearly 70% heavier than the hulking SFe engine-- he must have thrown that in to see if people were paying attention. Far as we can tell from the letters in Trains, no one was. He must have been appalled.
More to follow.
The article kind of made sense when I first read it at the end of 8th grade, but less so after taking a engineering thermodynamics class in my senior year in college.
Just for grins, I dug out my thermo textbook and looked up the steam tables - assuming isentropic performance from an engine, one could get maybe 30% more power out of steam at 500psi & 700F versus 240psi & 700F. This implies that a more accurate formula would have been grate area times pressure to (say) 0.4 power.
- Erik
The NP 2-8-8-4's grate area was initially 182 SF, but it was later reduced to 161.4 SF because of drafting/combustion problems.
The question that I wanted to ask was referencing the Quality of Coal Burned in the various steam locomotives. By no means am I a technical person, so I may be overly simplistic, but it seems to me that the Quantity of coal, plus draft, and combustion creat the BTU's needed; the quality of the available coal to be combusted would be a consideration in the final performance delivered. and the one thing missing from these conversations as well as the ones on the previous link is exactly the bearing of coal quality on the equations.
reference from this link: http://geology.about.com/od/mineral_resources/a/aa_nutshellcoal.htm
The UP's Big Boys, as I understand it were designed to burn a lower grade of Wyoming coal. The Allegeheny was designed to burn various grades of Appalachian coal ( either Bituminous or Anthracite?). Illinois Central burned available coal from Illinois mines and Kentucky mines ( my guess it was bituminous, but I am unsure about its quality). The Katy, as I had said burned a local coal from company mines in Kansas ( it was poor quality but readily available.) Santa Fe utilized oil, and may also as well used coal for fuel (not completely sure about that) ?
My questyion is would not the quality of fuel burned, be a factor in the functioning of grate size and the individual locomotives steaming ability ?
The quality of the coal as fuel definitely had an effect. The NP Yellowstones had their enormous fireboxes because they were designed to get the most of the low-grade coal that they burned. Lloyd Arkinstall, in one of his articles about firing for PRR in New Jersey, commented on the difference between the Westmoreland County coal supplied to passenger power and the West Virginia clinker coal he was stuck with on his local freight.
So Le Massena calculated the "potential power" (pressure time grate area) for a bunch of engines, along with their "power" per ton of engine weight, which was his criterion of merit. Since in his view merit was roughly proportional to boiler pressure, his favorite engines couldn't have much less than 300 psi. The SFe 3460-class 4-6-4, 3765-class 4-8-4 and 5001-class 2-10-4 all had 300 or more, and they all were at least tied for largest grate area of their type (except for the NP dirtburner 4-8-4s, which used lower pressure). So he concluded "AT&SF was the uncontested leader in three-, four-, and five-driving-axle locomotives of conventional design." Uncontested! Nobody can accuse the guy of being afraid to stick his neck out. His locomotive ratings didn't seem to make much impression, but his railroad ratings have stuck pretty well-- they're now conventional wisdom, unfortunately. Like lots of fans he figured the railroads would do better if they'd just run their trains faster: "Meanwhile, however, a few railroads were relying more on speed than on tonnage to give themselves better operating statistics while supplying better service to their shippers. Among these heretics were Nickel Plate, St. Louis Southwestern, Santa Fe and Union Pacific." "Like the Santa Fe and unlike many other roads which misapplied their high-power engines, UP held down tonnages, allowing its locomotives to run at high speeds and thus deriving from them the most work in the least time at the least cost. The financial records of these carriers are convincing evidence of their unorthodox operational philosophy."
They got better stats and lower costs by being heretical and unorthodox... we need details on that. They will follow.
I don't have access to Railway Engineering (Hay), but I do remember rated boiler horsepower factors in grate area, direct heating surface, firebox and flues, indirect, superheater steam tubes in the flues, and boiler pressure. I think a factor for bituminous coal was assumed. It seemed the efficiency was measured as the proportion between pressure in the boiler and in the piston having a lot to do with steam flow. FYI, I calculated that a fairly large, later series C&NW E-Class Pacific put out about 2,500hp.
The grate area alone would yield different results than for boiler power; and La Massena had an argument for discounting the other factors in his rating system.
Would a measure of current fixed utility power plant's boiler pressure give a good balance of higher pressure vs more complex piping??
Say we're deciding what tonnage to give to our new 2-8-4s on a railroad where the ruling grade isn't too tough-- 0.5 %, let's say. We try a 3500-ton train and the engine makes the grade at 12 mph; we try a 2500-ton train and it does 25 mph over the summit. If we assign 2500 tons instead of 3500 our ton-miles per train-hour on the grade will be 49% greater.
Far as we can tell from his article, Le Massena takes it for granted that more ton-miles per train-hour means lower total cost to run the railroad. Better service for the shippers and lower costs-- what's not to like?
Seems simple enough, doesn't it? But not simple enough for lots of railroads, who unaccountably persisted in assigning 3500 tons to their 2-8-4s. Le Massena's conclusion: railroads were run by blockheads.
I can't blame you for assuming I must be setting up a straw man-- surely he couldn't be that serenely obtuse? And maybe he can't be-- but the article gives no hint of any analysis beyond the seeming parody given here. More quotes to follow.
"Lima Locomotive Works, however, was not in agreement with this method of railroading; its 1925 experimental 2-8-4 with large boiler, big grate area, small cylinders, and bigger drivers was designed to deliver its maximum power at higher speeds. Excellent over-the-road performance was in direct opposition to the prevalent maximum-tonnage, minimum-speed gospel of current popularity. Despite the 2-8-4's immediate success, any number of tonnage worshipers refused to accept the new doctrine of speed first, tonnage second."
The new doctrine, fortunately conceived by Lima. But I'm guessing Lima wasn't trying to force any new doctrines on the railroads-- they were in the business of selling locomotives, and the way to do that is to build locomotives that do the job the railroad wants done. They intended the 2-8-4 to pull the same drag tonnage as a 2-8-2 while burning less fuel at drag speed and making better speed once past the ruling grade. Some railroads would have "fast freights", and the 2-8-4 was intended to be well suited to them too-- but Lima didn't ask the railroads to reduce train tonnage, on the "fast" freights or the drags.
The 2-8-4 wasn't actually "designed to deliver its maximum power at higher speeds". It was designed to deliver higher power, which would inevitably be at a higher speed than on the older engine. Maybe the old engine was good for 2500 dbhp at 25 mph and the 2-8-4 could do 3500 at 35 mph-- that's great, but if Lima could have found a way to get the 2-8-4 to do 3500 dbhp at 25 mph they would have jumped at the chance.
Dear Tim,
timz Some will ask: if it's true he made such an obvious error, why haven't the legions of razor-sharp railfan nitpickers mentioned it? Well, on page 41 he favorably compares the SFe 3460-class (412,000 lb "total weight") to an IC 4-6-4 (692,000 lb "total weight"). Presumably he didn't really think the IC had a 4-6-4 nearly 70% heavier than the hulking SFe engine-- he must have thrown that in to see if people were paying attention. Far as we can tell from the letters in Trains, no one was. He must have been appalled. More to follow.
is this correct, as I may understand you, he made mistakes on purpose? Maybe it was just a typo?
timz Say we're deciding what tonnage to give to our new 2-8-4s on a railroad where the ruling grade isn't too tough-- 0.5 %, let's say. We try a 3500-ton train and the engine makes the grade at 12 mph; we try a 2500-ton train and it does 25 mph over the summit. If we assign 2500 tons instead of 3500 our ton-miles per train-hour on the grade will be 49% greater. Far as we can tell from his article, Le Massena takes it for granted that more ton-miles per train-hour means lower total cost to run the railroad. Better service for the shippers and lower costs-- what's not to like? Seems simple enough, doesn't it? But not simple enough for lots of railroads, who unaccountably persisted in assigning 3500 tons to their 2-8-4s. Le Massena's conclusion: railroads were run by blockheads. I can't blame you for assuming I must be setting up a straw man-- surely he couldn't be that serenely obtuse? And maybe he can't be-- but the article gives no hint of any analysis beyond the seeming parody given here. More quotes to follow.
I do not have the article, maybe he meant running it hours for hours just on a grade, the higher HP-engine is no bonus, there.
lars
timz"Lima Locomotive Works, however, was not in agreement with this method of railroading; its 1925 experimental 2-8-4 with large boiler, big grate area, small cylinders, and bigger drivers was designed to deliver its maximum power at higher speeds. Excellent over-the-road performance was in direct opposition to the prevalent maximum-tonnage, minimum-speed gospel of current popularity. Despite the 2-8-4's immediate success, any number of tonnage worshipers refused to accept the new doctrine of speed first, tonnage second." The new doctrine, fortunately conceived by Lima. But I'm guessing Lima wasn't trying to force any new doctrines on the railroads-- they were in the business of selling locomotives, and the way to do that is to build locomotives that do the job the railroad wants done. They intended the 2-8-4 to pull the same drag tonnage as a 2-8-2 while burning less fuel at drag speed and making better speed once past the ruling grade. Some railroads would have "fast freights", and the 2-8-4 was intended to be well suited to them too-- but Lima didn't ask the railroads to reduce train tonnage, on the "fast" freights or the drags. The 2-8-4 wasn't actually "designed to deliver its maximum power at higher speeds". It was designed to deliver higher power, which would inevitably be at a higher speed than on the older engine. Maybe the old engine was good for 2500 dbhp at 25 mph and the 2-8-4 could do 3500 at 35 mph-- that's great, but if Lima could have found a way to get the 2-8-4 to do 3500 dbhp at 25 mph they would have jumped at the chance.
Timz, the Lima design is typified by the NYC A-1 class (and used also by IC and ATSF) doesn't seem to have been as successful as the design created by the "Advisory Mechanical Committee" (Van Sweringen roads). The Lima design used larger cylinders and 63" Driving Wheels, and used Limited Cutoff to keep TE within reasonable adhesion limits. The design featuring smaller cylinders combined with reasonable boiler pressure originated with the AMC rather than Lima. The first AMC designed Berkshires were the Erie S-1design built by Alco-Brooks. Lima built the S-2 and S-4 batches, while Baldwin built the S-3 batch, these locomotives introduced the larger diameter Drivers to the Berkshire design which had previously used 63" drivers like many Mikados. The design was then refined into the classic NKP S-1 Berkshires with a more balanced, smaller cylinder and longer stroke, cmbined with a larger Driving Wheel diameter design.
Lars Locois this correct, as I may understand you, he made mistakes on purpose? Maybe it was just a typo?
"The year 1937 represents the high-water mark of steam locomotive development and construction. During the previous two decades power-producing capabilities had doubled; of vastly greater significance was the fact that power per ton of locomotive weight had also virtually doubled. One specific example is revealed by comparing the latest Santa Fe 4-6-4 (300 pounds pressure, 99 square feet of grate, 412,000 pounds total weight) with Illinois Central's 4-6-4 conversion from Lima's A1 model (265 pounds pressure, 100 square feet of grate, 692,000 pounds total weight)."
Could he really have thought he was comparing engine weights?
beaulieu the Lima design is typified by the NYC A-1 class (and used also by IC and ATSF) doesn't seem to have been as successful as the design created by the "Advisory Mechanical Committee" (Van Sweringen roads).
timzbeaulieu the Lima design is typified by the NYC A-1 class (and used also by IC and ATSF) doesn't seem to have been as successful as the design created by the "Advisory Mechanical Committee" (Van Sweringen roads).Railfan books/articles like the later engines better, and limited cutoff sure went out of fashion after 1930 (except on SFe). Aside from that, what do we know about their success?
Railfan books/articles like the later engines better, and limited cutoff sure went out of fashion after 1930 (except on SFe). Aside from that, what do we know about their success?
I meant to correct the reference to Santa Fe Berkshires and change it to Missouri Pacific. The Santa Fe's Berkshires were just enlarged Mikados. The Lima designed Berkshires on NYC's B & A amounted to 55 locomotives in one order. They were never duplicated, and were replaced by diesels fairly soon after WW2. Both Missouri Pacific and Illinois Central rebuilt their fleets of Berkshires to totally different types of locomotives, which clearly indicates that they were unsatisfactory as built.
I never could figure out where the "total" weight figure for IC's 4-6-4 came from in the article. The best I have is that it weighted 405,600 lbs, excluding tender. The predecessor 2-8-4 weighed 393,500 lbs, also excluding tender. Typo? Maybe, but I doubt it was an intentional "gotcha" figure. If anyone has ever checked the complete table in the Trains article, there are several inaccuracies, perhaps due to rounding or other causes. I never found them until PC's came into play in the 1980s and I could put the entire table into one spreadsheet very quickly.
AFAIK, Santa Fe had 10 early-design 2-8-4's purchased from B&M - 4101-4104 and 4193-4198. These weren't extended mikados.
The IC 4-6-4 weight would be very close to that of the NYC A-1 2-8-4. It's a matter of weight redistribution, moving the driving wheels forward, in part because of their larger diameter. My guess is that the IC engine had 216,000 lbs on the drivers, 2/3rd of the difference on the trailing truck and the remainder on the lead truck.
As a follow-up, I see you gave a weight for the A-1 of about 393,000 lbs. That would put approximately 59,000 lbs on the lead truck (29,500 lb axle load) and 118,000 lbs on the trailing truck (59,000 lb axle load) with a 2:1 ratio. A 3:2 ratio would result in 35,400 lb and 53,100 lb axle loads on the respective lead and trailing trucks.
Didn't the IC engines get cast steel beds and cylinders when rebuilt?
More quotes from the article--
"The [CB&Q] 2-10-4 was operated at speeds well below that for peak power (about 20 mph)...The Burlington 2-10-4's big boiler, 107-square-foot grate, and 250-pound pressure, thus misapplied, were more ornamental than useful in the production of ton-miles at minimum cost."
CB&Q got the 2-10-4s to haul 8000-ton coal trains out of southern Illinois; ruling grade against the loads may have been 0.3%, which would indeed slow them to 20 mph or so-- when they were on that grade. But most of the time they wouldn't be on that grade, so most of the time they'd be making better speed, maybe even good enough to satisfy Le Massena. No doubt he'd prefer that they reduce the assigned tonnage, but he still makes no attempt to explain how that would lower costs."When the [SP] cab-forwards were used in passenger service over difficult profiles at high speeds, their performance was magnificent; yet their primary use was in low-speed freight service, three or four to a train, operating well below the ultimate capacity of boiler and machinery."
In the 1940s SP rated its newest 4-8+8-2s at 1450 tons eastward over Donner Pass, with which they could apparently make 15 mph or better on the steepest part of the climb. Not good enough for Le Massena-- one wonders what tonnage rating he would have approved. Note that if they cut trailing tonnage by, say, 40%, they'd only be cutting total tonnage by 30%, so the increase in ton-miles per hour won't be that great.
I was underwhelmed when I first read about this method of power ranking, and the more I thought about it, the more exceptions I could find, even when I held the caloric value of coal constant. (This thread's discussion of BTU values has been very useful to explore a different area of disagreement.)
A central problem was the dismissal of the boiler. Same grate, same pressure and I was pretty sure you'd have different results with different-sized boilers.
Then I wondered about the effect of superheating the steam that's produced? So I used the "equivalent heating surface" calculation of 1.5 x the superheater's sq footage divided into the total heating surface. That brings the boiler into play and, as I'll show in a moment, takes a long step toward making this a useful way to compare locomotives.
But then I thought of oil-fired locomotives - they don't have "grates" in the sense of spreading the fuel out over a single surface. They burn their fuel in a volume bounded by the firebox. So I substituted firebox heating surface for grate area, which I think allows for an apples-to-apples comparison of oil burners with coal burners.
And, I thought, if grate area is your only measure, then clearly Wootten anthracite-burning fireboxes take the palm. Their grates are relatively huge - at least twice the area and often more compared to an equivalent narrow-firebox design. What I discovered is that these fireboxes usually had very similar direct heating surface areas, so soft-draft, thin-fire apparatuses such as these can be compared.
After tinkering some more, I came up with a formula that takes into account the superheater's contribution as outlined above,
the higher rates of evaporation per square foot of heating surface for fireboxes compared to tubes (about 6 to 1),
driver diameter (fewer RPM means fewer "lungfuls" per minute or per mile).
It was a lot of fun and the resulting number works pretty well for all kinds of steam locomotives. But along the way, I became satisfied that using firebox (or direct) heating surface area (this includes syphons, arch tubes, combustion chambers...) times the boiler pressure times the superheater ratio(x 1.5) can give a shorthand comparison.
Steve Llanso, Locobase.
feltonhillThe best I have is that it weighted 405,600 lbs, excluding tender.
IC #1 was 388000 lbs, excluding tender. It was the only attempt at a freight Hudson, but was too slippery.
C&NW, CA&E, MILW, CGW and IC fan
feltonhill The NP 2-8-8-4's grate area was initially 182 SF, but it was later reduced to 161.4 SF because of drafting/combustion problems.
The grate size was to burn the (Rosebud) coal, which was a very poor but cheap grade of coal. The Z5 was not a high capacity type of locomotive and was used in pusher service almost entirely after the Z6, Z7 and Z8's were running. The Z5 was very large at the time it was built, but a very slow locomotive compared to the Z8's or the Big Boys. I am not sure about the exact name of the coal, but it was cheap and so the NP engines grate size had to be much larger to get proper amount of heat out of it.
CZ
CZ:
The source of coal for the NP Yellowstones (as well as many other NP steam engines in the Rocky Mountain area) was the company's open-cast mine near the town of Colstrip, Montana. Popularly referred to at the time (and in railfan legend) as lignite, this is in fact a sub-bituminous coal of about 8,300 BTU. Today, we call this "Northern Powder River Basin" coal and it is mined from the exact same seam for large mine-mouth power plants owned by Colstrip Energy and Pacific Power & Light, and for numerous northern plains and Midwestern utilities such as Detroit Edison.
NP's coal supply west of the Rocky Mountains was the company mines at Roslyn, Washington.
Most railways that served major coal-producing regions owned their own coal mines and sourced as much coal as possible from their captive mines. Some of these coal companies bore the same name as the railroad (e.g., Union Pacific Coal Company) and some did not (e.g., Utah Fuel Co. of the D&RGW; Clearfield Coal Co. of the NYC).
The NP's use of the very large firebox on the Yellowstone was an attempt to gain better efficiency from the low-value coal it had close at hand in Montana, as opposed to higher heating value coal from Roslyn, the Illinois Basin, or "Lake Coal" via Duluth, which was considerably more expensive due to transportation costs to carry it to Montana to put into a locomotive tender. Both Railway Age and Coal Age covered the NP's effort extensively as it was of great interest to both the railway and coal industries, the former hopeful that it would be technically possible to burn such poor-quality coal and still generate adequate transportation without high maintenance and locomotive failure expense; the latter hopeful that it would create a market for otherwise worthless coal in an era when oil and natural gas were rapidly encroaching on the railway, domestic, and industrial heating and process market. Colstrip was a very advanced mechanized mine for its time, and of great interest just for its very low mining costs.
RWM
Railway ManColstrip was a very advanced mechanized mine for its time, and of great interest just for its very low mining costs.
Colstrip was a very advanced mechanized mine for its time, and of great interest just for its very low mining costs.
The 9 cu. yd. dragline that was part of the original opening of the mine ca 1923, was still in use in 1971 along with the "small" electric shovel (ISTR also about 9 cu. yd.).
Prior to opening the mine in Colstrip, the NP was getting its coal from the mines around Red Lodge. The Red Lodge mines were underground and thus labor intensive, which was particularly important after the wage inflation due to WW1. Another issue was safety, the worst mining disaster in Montana history was happened in Bear Creek (a very few miles east of Red Lodge) during WW2.
The Red Lodge mines were gassy. The geology wasn't very fun, either.
While Le Massena concedes that the design of NP's power took consideration of the low-grade coal that was available, he implied that even better performance would have been possible with good coal.
CSSHEGEWISCHWhile Le Massena concedes that the design of NP's power took consideration of the low-grade coal that was available, he implied that even better performance would have been possible with good coal.
GP40-2CSSHEGEWISCHWhile Le Massena concedes that the design of NP's power took consideration of the low-grade coal that was available, he implied that even better performance would have been possible with good coal. Better performance would have been possible with better coal AND a complete redesign of the combustion area. It is not as simple as just using better grade coal in the existing design. Railroads that had the best steam coal in their backyard such as the N&W, C&O, and B&O had their boilers, specifically the firebox/combustion chamber area specifically designed to maximize the potential of such coal. Same with powerplant design. You can't take a plant that was designed to used Powder River coal, and start using fast burning/high BTU Pittsburgh Grade coal. The entire combustion area would need to be redesigned. Le Massena problem was he often passed his uninformed opinions off as facts to the railfan community.
To start with, is there a point where a large grate with high-BTU coal might melt the crown sheet?
Would the flues be sufficient to carry off the hot gases from the firebox-combustion chamber?
Would superheaters be large enough for adequate steam flow?
Would the firebox-combustion chamber and flues absorb that heat for steam production efficiently?
Finally, would these improvements reach peak output at 40 mph, about the limit for 63" drivers; or would the engines be considered "slippery!"
I wish to defend both the Lima A-1 2-8-4's on the Boston and Albany and their near cousins with Coffeen fedwater heaters ("the John L. Lewis look") on the nearby B&N. Both did their jobs, Both crossings of the Birkshire Moutains were early candidates for dieselization, but not because of any problems with the Birkshires. The B&A's did see further use on the NYC system and were seen later in Michigan, Ohio, Illinois, and Indiana, often with larger tenders. And obviously the AT&SF thought enough of the B&M's to buy some.
That does not prevent from admiring the NKP-PM-W&LE-C&O design even more.
CSSHEGEWISCHLe Massena's problem was he often passed his uninformed opinions off as facts to the railfan community.
I was under the impression that LeMassena was more accurate and/or better informed than Lloyd Stagner. Regarding inaccuracies in printed articles and books, I became very frustrated with Lloyd Stagner's works many years ago--and refuse to buy anything that has his name on it. Why? Well, at least where Santa Fe steam is concerned, he likes to quote lots of numbers, and either his writing or the editing on the part of Morning Sun Books was shoddy. Where Stagner quotes Santa Fe steam data, especially in The Santa Fe in Color book series, there appear to be several mis-quotes. This does not become fully apparent until you read the cited sources (S. Kip Farrington's The Santa Fe's Big Three, which included many actual Santa Fe loco test reports). Always go back to the original data source and be wary of locomotive horsepower and/or tractive effort ratings in print. Recent Classic Trains Steam special issues have also included articles that appear to conflict with each other where locomotive data is concerned.
This thread makes very interesting reading, especially for someone like myself who has read LeMassena's Articulated Steam Locomotives of North America books...
Regarding great, or potentially great engines, or relatively unsung engines:
The Santa Fe hudsons were known for beinq quite slippery, and in that regard are not as fondly remembered by most SF fans as the 4-8-4's.
The 5001 and 5011-class Santa Fe 2-10-4's were marvelous engines producing very high horsepower (if I recall correctly, well above 5000 horsepower for a 30 mph band of usable speed according to the actual test data published in S. Kip Farrington's The Santa Fe's Big Three.) but because they toiled mostly in the New Mexico desert, they are largely forgotten. In the curvy areas of Arizona, the 2-10-2's apparently performed better--so I think many folks forget about or vastly under-rate the 2-10-4's.
Also--UP's 4-12-2's were never modernized with roller bearings (other than on the Gresley gear of some) becaue Otto Jabelman decided he absolutely hated them, and spent much of his career trying to get rid of them or replace them--even basically ignored potential U.S. government war-era funding for roller bearings which would have dramatically upgraded their performance and especially their durability. Because they never received some "modern" improvements, we'll never know what the real potential of those engines might have been. As engine 9000 was tested in 1926, peak horsepower was 4917 indicated at the cylinders at 37 mph (reported in UP Type, Vol. I) and later improved versions most certainly did better--but there's no data regarding how much better the later versions performed. What a shame.
John
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