BaltACD daveklepper I was a Junior engineer (summer job between Junior and Senior years at MIT) at EMD, summer 1952, and saw the F7s prepaired for the N&W tests, four units, ABBA, if memory correcdt, painted UP yellow scheme. I think they were souped up a bit, more than regular horsepower, 1750 per unit instead of 1500? Sounds like they may have been the prototype F9 package as the F9's and GP9's were 1750 HP machines.
daveklepper I was a Junior engineer (summer job between Junior and Senior years at MIT) at EMD, summer 1952, and saw the F7s prepaired for the N&W tests, four units, ABBA, if memory correcdt, painted UP yellow scheme. I think they were souped up a bit, more than regular horsepower, 1750 per unit instead of 1500?
Sounds like they may have been the prototype F9 package as the F9's and GP9's were 1750 HP machines.
There is evidence that HP on both EMD and GE locomotives is a matter of fuel-rack settings.
The rating of a locomotive, however, is not simply a matter of releasing the locomotive from the factory with an advanced fuel rack. There are changes between successive models so that the locomotive can hold up in service with the prime mover and the traction equipment pushed that much harder.
So you suppose those really were F7s with a higher fuel rack setting and that the true F9 model waited further mods that the locomotive could stand up in service that way? There is also evidence that EMD goofed with releasing a model with higher HP out of the same gear -- was that the SD50 story? See https://en.wikipedia.org/wiki/EMD_SD50
If GM "killed the electric car", what am I doing standing next to an EV-1, a half a block from the WSOR tracks?
I was a Junior engineer (summer job between Junior and Senior years at MIT) at EMD, summer 1952, and saw the F7s prepaired for the N&W tests, four units, ABBA, if memory correcdt, painted UP yellow scheme. I think they were souped up a bit, more than regular horsepower, 1750 per unit instead of 1500?
Speaking "engineer-to-engineer", the claims that EMD "cheated" by calibrating the F7s for what would be the HP of the later F9 model or that N&W goosed the performance of the Y6b by going to 310 PSI boiler pressure or added more weight to the front driver set is immaterial. EMD was increasing HP with successive models and that was the trajectory Diesels were on. 310 PSI boiler pressure my have been a cheat for a riveted boiler, but were steam to stay around, it was not an entirely implausible improvement -- it was not in the realm of exotic boiler designs.
That a Diesel was, hypothetically, 10% more effective in N&W operations is within the engineering margin-of-error of testing. Yes, 10% differences are greater than one's profit margin in railroad practices, but that has to be weighed against all the other considerations of scrapping sunk investment in steam to make the change and so on.
The decision to go with Diesels ultimately had to be based on where management saw the trajectory for future improvements to it compared to what was considered steam development stagnating for reaching upper limits.
daveklepperI was a Junior engineer (summer job between Junior and Senior years at MIT) at EMD, summer 1952, and saw the F7s prepaired for the N&W tests, four units, ABBA, if memory correcdt, painted UP yellow scheme. I think they were souped up a bit, more than regular horsepower, 1750 per unit instead of 1500?
Never too old to have a happy childhood!
I think I read that article.
The reason I was thinking FTs was that an ABBA FT set "barnstormed" the major railroads and convinced many managements that the time for Diesels on mainline freight had arrived. I guess the demonstration on N&W occurred later than that time to persuade late-adopter N&W.
Paul Milenkovic Yes, it was F7s vs the Y6b https://www.american-rails.com/y.html
Yes, it was F7s vs the Y6b
https://www.american-rails.com/y.html
Another article is "N&W's Secret Weapons", Trains, Nov 1991.
Paul MilenkovicAs to the conjugated duplex with the crank axles and inside connecting rods, there is that precedent from France -- Plate 87 in Alfred Bruce's book.
For those with no Steam Locomotive in America, there is a picture (and some discussion) of the PLM 151A on the inimitable Douglas Self Site:
http://www.douglas-self.com/MUSEUM/LOCOLOCO/duplex/duplex.htm
This is interesting for its linked cutoff, which at least attempted to keep the piston thrusts proportionately equal: if you look at the 180-degree-opposed design you can see that this will keep the thrusts taken through the inside 'conjugating rods' minimized, so their throw can be less, their mass lower, and the axles and webs involved stronger. Still doesn't help the situation if you want to use American-style roller bearings, though -- there are solutions, but not particularly simple or light ones...
A little more discussion, and a somewhat better picture, here.
Now I suppose that such a locomotive was built and operated in France doesn't say much as they put up with everything from the Crampton design in the 19th century to the de Glehn 4-cylinder compounds with the thin webs for two inside LP cylinders driving a cranked axle and attendant bearing maintenance and breakage concerns.
The French experience is interesting, because their fuel cost was always so exorbitant they could value 'thermodynamic improvement' much more than most American 'operators' did; they had a better class of 'mecanicien' willing to control the sometimes convoluted controls (e.g. of a typical de Glehn-du Bousquet locomotive, which was exquisite when fine-tuned, but who has the time to tinker with two sets of valve gear when running?) and, during the 'golden age' of the 1930s, had an artificial politically-imposed top speed limit that required the locomotives to have great acceleration and relatively high performance but did not value absolute high speed at all. Advanced compounds and multiple-cylinder engines make sense there much more than they would in a North American context.
Not to say they didn't have their share of what the Germans call "Fehler" - the Raymond valve gear and the 'progressive development' of the salmon-rod Cossart gear being two somewhat amusing examples. We have discussed the 160 A1 and its testing on this forum before; I don't consider it a mistake, but some of its approaches are a bit ... abstruse.
On the other hand, the ACE Project ran the 614 as a test/publicity stunt in coal service over the line where the H8s once ran, and the 614 was as misapplied to the tonnage and the grades and the speed (fast freight coal train?) as the H8s.
Ross, bless his heart, seems to have had no idea whatsoever about how to run actual scientific locomotive testing. How you think results with an overtly leaking firebox are worth more than railfan-excitedment cred is even more of a mystery than testing a locomotive like a C&O J3a at high output without a functioning feedwater heater. It is not difficult to see why Mr. Rowland and Mr. Wardale had a fairly dramatic parting of the ways (and perhaps, why the two have fairly dramatically different accounts of it). It is more difficult to try to figure out why Mr. Porta signed off on this trash wallow.
Not saying how ACE could have had the money to restore one, but a Y6 with "full proportional IP injection" would have been a much better competitor to Diesels in that service, much as a modified Y6b convinced Norfolk and Western to hold its own against a brace of FTs?
I've never heard of N&W testing FTs; tell me more.
There is comparatively little to be learned about actual economy from the F-unit testing in the 1950s, as it's pretty clear that both sides 'cheated' -- someone once noted that N&W could have had very effective revenge on EMD by requiring any production order of Fs to produce 'equivalent performance' with full warranty. In my opinion even N&W couldn't get a locomotive with 315psi pressure in a riveted boiler to work very well long-term, and I never saw any indication they were interested in adopting welded construction (e.g. including something like downhand submerged-arc welding for the shell, and a vertical furnace like Alco's for normalizing) which is almost the only thing that makes higher pressures economical; the chain-grate watertube boiler they adopted instead was an interesting thing to keep maintained but not an impossible one ... it just wouldn't scale to the actual output power that would make a STE 'pay' in their service compared to a good conventional reciprocating locomotive.
Note that there is a bit more to the proportional IP injection than just nominal receiver pressure. When done right (imho) the approach prevents some, perhaps all, of the need to perform inline reheat on the receiver steam (as in the 160 A1), in part because there is little restriction on the degree of superheat that the injection arrangement itself will tolerate, so very effective superheat to reduce both wall and nucleate condensation in the LP charge 'as a whole' can be achieved without needing to incur damaging effects of differential thermal expansion or impaired tribology in even high-mass-flow operation.
The Y-6b may have won the battle (barely) against a quartet of F7's in 1952 but the diesels still won the war.
As to the conjugated duplex with the crank axles and inside connecting rods, there is that precedent from France -- Plate 87 in Alfred Bruce's book.
On the other hand, the ACE Project ran the 614 as a test/publicity stunt in coal service over the line where the H8s once ran, and the 614 was as misapplied to the tonnage and the grades and the speed (fast freight coal train?) as the H8s. Not saying how ACE could have had the money to restore one, but a Y6 with "full proportional IP injection" would have been a much better competitor to Diesels in that service, much as a modified Y6b convinced Norfolk and Western to hold its own against a brace of FTs?
CSSHEGEWISCHAt the risk of being shot and deported, I am beginning to think that the T1 Trust is building the wrong locomotive. Instead of building a T1, apparently to prove its capabilities, they should have considered building an H-8 to prove that it was actually a fast freight design.
No, you have it backward. There are two H-8s in existence, which with permission could be restored for testing at a fraction of 'replication' cost. And I think it rather well established (from a number of sources) that the H-8 was definitively a fast freight design, to the extent that any modern simple articulated would be. It's the intentional use of the design for much of its service life in service well below the peak of its horsepower curve that is at issue here.
What would be appropriate is a 'replica' either of a Y-6-size 2-8-8-2 with full proportional IP injection, or an adapted Y-7, to establish that those would actually be fast freight designs.
Withuhn was an excellent historian, and I have neither the desire nor the intent to abuse his memory, but he has had some remarkable run-ins with reality in modern steam design, most particularly with the conjugated duplex system for the ACE3000. Aside from not recognizing second-order issues with the balancing, he never seems to have provided an actual frame that would work, and the illustration of the geometry in the ACE patent itself is almost pathetic, with the arrangement as drawn being very evidently inadequate and little mention being made of the actual strength distributions required in the frame. In my opinion, Hirsimaki is a better scholar (at least in terms of Lima tech) and J. Parker Lamb, for all his faults, understands the technology better, and I'd listen to either of them sooner than accept what is suspiciously like the old-railfan's-chestnut account of the Alleghenies being misused without a much better technical account of what the 'fix' should include.
At the risk of being shot and deported, I am beginning to think that the T1 Trust is building the wrong locomotive. Instead of building a T1, apparently to prove its capabilities, they should have considered building an H-8 to prove that it was actually a fast freight design.
charlie hebdo timz C&O ordered ten 2-6-6-6s, and supposedly set the HP record. So why reorder? After 1943 they were free to order big 2-8-8-2s, and keep the fans happy.
timz C&O ordered ten 2-6-6-6s, and supposedly set the HP record. So why reorder? After 1943 they were free to order big 2-8-8-2s, and keep the fans happy.
timzC&O ordered ten 2-6-6-6s, and supposedly set the HP record. So why reorder? After 1943 they were free to order big 2-8-8-2s, and keep the fans happy.
Do you actually think that or is that supposed to be sarcasm? Sarcasm is "a sharp, bitter, or cutting expression or remark; a bitter gibe or taunt". Sarcasm may employ ambivalence, although sarcasm is not necessarily ironic.
Withuhn knew that a big 2-8-8-2 could pull more tonnage up a given grade than a 2-6-6-6. All us fans know that, and C&O certainly did.
What did Withuhn know about 2-8-8-2s vs 2-6-6-6s that C&O didn't know?
Nothing -- and maybe he knew that. But he figures C&O knowingly chose a stupid engine. Fans always like to think railroads are run by blockheads.
timz PNWRMNM Ellis decided they had to beat the N&W in terms of HP and that a 2-6-6-6 was the way to do it. That's what railfans like to think. Aside from the general implausibility--
PNWRMNM Ellis decided they had to beat the N&W in terms of HP and that a 2-6-6-6 was the way to do it.
That's what railfans like to think. Aside from the general implausibility--
Timz,
You are not arguing with me but with Withuhn who I am 100% confident knows more about steam engines than you and I put together.
What was truly striking to me was that they were no better at the job than their predecessor 2-8-8-2s were. C&O spent more money to get no better perforance with extreemly high axle loadings which put more stress on the entire track structure which had to have increased track maintenance exense and probably caused a few derailments that otherwise would not have happened.
My personal opinion is that Withuhn is correct. Read the book!
Mac
PNWRMNMEllis decided they had to beat the N&W in terms of HP and that a 2-6-6-6 was the way to do it.
Don't think C&O mentioned the 1943 test results in Rwy Age or Rwy Mech Engr (or any other publ?). They knowingly ordered a stupid engine, planning to set the horsepower record -- then didn't publicize the record when they supposedly got it?
C&O ordered ten 2-6-6-6s, and supposedly set the HP record. So why order more of them? The HP record's in the bag; after 1943 they were free to order big 2-8-8-2s, and keep the fans happy. They could run the 2-6-6-6s Russell to Toledo and get a 16-driver railfan-approved engine to haul coal to Alleghany.
Don't be too hard on the Advisory Mechanical Committee. After all, they did come up with excellent 2-8-4 and 2-10-4 designs.
I am surprised that no one has mentioned William L. Withun's analysis in his new 'American Steam Locomotives'. Chapter 18 is about the Big Boy and the Allegheny.
For each he describes the development process and then their performance in the roles they were designed for, after spending much time earlier in the book on the issues of Gross Ton Miles per Hour and the economics of producing those GTMPH. The Super Power salesmen were selling some combination of increased speed and increased tonnage ratings, and it was not a hard sale if the competitor was a 20 year old 2-8-2.
The C&O went wrong from the start. The AMC was its own little fiefdom. The only credible explanation for what happened is that Chairman Daniel Ellis was green with envy at competitor N&W's class A 2-6-6-4 which developed more than 6,000 drawbar horsepower. Ellis decided they had to beat the N&W in terms of HP and that a 2-6-6-6 was the way to do it. The design started ot heavy, Lima found another 30,000 pounds in the design that the C&O overlooked and it got heavier as further changes were made, resulting in very high axle loadings.
The AMC did NOT talk to the operating guys about what they needed. The result was that the Alleghney had no impact on the opertion of the territory it was designed for. Train weight and length were unchanged due to other operating restrictions. Worse yet, the C&O engines had a lower tonnage rating than did the Big Boys (of about 6,000 hp) on equal grades, both at 10-15 MPH. Big Boys were rated for 4,400 tons on 1.14% grades while the Alleghneys were rated for 2,950 on their 1.14% grade. The C&O grade was not compenstated, which knocked the Alleghenys down by about 800 tons. Adding back 800 tons, we get an adjusted rating of 3,750 tons.
Why the disparity when the Alleghney has 7,000 hp and the Big Boy about 6,000 hp? Because the BB has two more powered axles and higher tractive effort all the way up to 30 MPH.
Withun concludes that the Alleghney was '... simply the wrong design for the C&O.' He goes on to suggest that a 16 driver engine with slightly bigger drivers than the (simple) H-7 but smaller than the Big Boy would have been a more economical choice for the C&O.
nhrandIn the article [Woodard] answers the question originally posed in the Forum, that is, was the Allegheny wasted by often being used on slow coal trains rather than in service where its high horsepower could be better applied.
Actually, this is something he DOESN'T address ... at least in the sense you mean.
He is advocating precisely that a design for slow-speed be optimized for efficient (hence, economical) operation in the specific services for which the locomotives are provided. We would not, for example, expect to see his '30s design for high-speed four-coupled locomotives adapted for 'secondary service' even if that included passenger work that might take advantage of high speed at some point. Note that this is less than a year later than his discussion of the 'Central Machinery Support' 2-12-6, which is perhaps interesting to consider as his 1928 thinking on a "12-drivered" locomotive; the effect of Eksergian's paper on effective locomotive balancing published that same year had not had much time to 'gain traction' in providing effective solutions for good balancing of relatively low-drivered locomotives (cf. the package that converted the T&P 600s from drag-freight Super-Power to relatively capable passenger-capable power in the 1930s as recounted in at least one Trains article).
That does not make the article worth any less from the standpoint of assessing what 'good contemporary choices' for motive-power design details in a particular service ought to be. I would ask only that we remember a considerable number of 'enabling technologies' in reciprocating-locomotive design were developed subsequently, sometimes with a terrible learning curve (ACL R-1s, anyone?) before their often frankly common-sense implementation was 'mainstreamed'.
... Woodard advocated using modern Super-Power specifically designed for branch line or secondary line service rather than relying on old, outdated power displaced from main line service.
Now, I am tempted to be a bit sarcastic and note you clearly have a Lima designer doing this discussion. You, I, and the person behind the tree would know, even by 1929, that the articulated trailing truck alone would make this a holy horror if, you know, the engine were expected to perform something like trailing-point backing moves or substantial reverse running on typical 'secondary' trackage of that era. We won't go into the fun of keeping complicated steam auxiliaries like FWH pumps running 'in the boonies' to keep the fuel bill minimized -- some railroads, C&O among them, recognized that even first-line large power might be "cheaper" to run without the complications at some rate of return far better than that of secondary service. Where he thought railroads would get the capital to buy these shiny new engines instead of working additional miles out of that paid-for cheap earlier power is unclear to me, even before the New Era came crashing down; what actually happened on some (perhaps many!) railroads was that the 'shiny new technology' came to be applied in rebuilds (to reset the tax clock on depreciation, etc., more than real tangible benefits in operation) instead of at full price on new locomotives -- Frisco 1351 and 1352 are poster children for this practice -- and one might suspect that this would be as true in the late '20s as in the late '40s.
The locomotive Woodard proposed was a light Hudson 4-6-4 with 69" drivers, 250 lbs. steam pressure and a tractive force of 50,700 lbs. with booster. The engine was proposed for dual service, mainly freight but also passenger service. A drawing of the locomotive was included and it appeared something like the A-1 with a similar articulated trailing truck but given the small drivers and large boiler there was a pronounced space between the leading truck and drivers. It even had tandem main rods and limited cut-off. Woodard said, "It is perfectly possible to replace practically all of these old and obsolete types with one single design of locomotive".
One likely problem that could easily be foreseen is that railroads wouldn't treat the 'replacement' single design relative to the capabilities of the various older locomotives it would replace -- one very important 'likelihood' being that the new engine would become treated just as C&O did the Alleghenies (or PRR, the T1s): flogged to increase perceived 'return on equity' by taking the full modern output as the number for calculating effective 'train ratings' for service.
To me, this suggests something that the English engineer Tuplin observed NYC doing with one of the Niagaras: by using a version of sliding-pressure firing, the engine could be made to do the work of an earlier-class 2-8-0 on the 2-8-0's consumption of fuel and water. Nifty ... until you consider All That Capital (and greater length, complexity, etc.) tied up doing that little job, and then starting to wonder if that was all being wasted when more cars could evidently be tied on and handled...
Woodard realized that many would scoff at the idea of buying a super-power locomotive for lowly service so wrote the following about the issue of applying super-power elements to low grade service: "These are the essential elements in locomotive design which produce power output at speed with economical performance. Objection may be raised that such provisions are not warranted in the class of service to which secondary locomotives are generally used and that full advantage cannot be taken of these power producing elements. The answer is that they are equally as useful in promoting economical operation as in producing high power output. And, moreover, we believe it will be found that such characteristics are highly desirable in a general service locomotive."
And here we have an unintentional echo of all those unsuccessful things from the 1920s that were aimed at 'increasing thermodynamic efficiency' ... but at a cost, or maintenance headache, or increased likelihood of road failures, that made any such Big Savings for years and years of fleet operation disappear with a sad sizzle as soon as the problems started to occur. Some of the 'best' of L.D.Porta's thinking has the same characteristics when you look carefully at how they would be long-term implemented.
The answer is almost always that robust, simple, and a bit wasteful is preferential to high-dollar saving of a few percent on what is already a gloriously inefficient thermodynamic 'cycle' for most secondary steam service. When we do see a good-performing 'general-purpose' locomotive for secondary service adopted ... it was a well-designed diesel-electric from Dilworth et al. (mind you, after an almost ridiculous false start designing the wrong kind of secondary-service power, the BLs) and not steam with its limitations at all.
nhrand LIMA'S WOODARD ANSWERS THE QUESTION Purely by coincidence I was paging through some old Railway Age magazines and found an article by W.E. Woodard, Vice President, Lima Locomotive Works, the man who designed the famous A-1 2-8-4 and is credited with introducing "super-power" locomotives. In the article he answers the question originally posed in the Forum, that is, was the Allegheny wasted by often being used on slow coal trains rather than in service where its high horsepower could be better applied. The article is titled MODERN LOCOMOTIVES FOR SECONDARY SEVICE, and appeared in the April 20, 1929 issue complete with several diagrams, charts and tables (Abstracted from a paper presented to a professional group). In the article Woodard advocated using modern super-power specifically designed for branch line or secondary line service rather than relying on old, outdated power dispalced from main line service. The locomotive Woodard proposed was a light Hudson 4-6-4 with 69" drivers, 250 lbs. steam pressure and a tractive force of 50,700 lbs. with booster. The engine was proposed for dual service, mainly freight but also passenger service. A drawing of the locomotive was included and it appeared something like the A-1 with a similar articulated trailing truck but given the small drivers and large boiler there was a pronounced space between the leading truck and drivers. It even had tandem main rods and limited cut-off. Woodard said, "It is perfectly possible to replace practically all of these old and obsolete types with one single design of locomotive". Woodard realized that many would scoff at the idea of buying a super-power locomotive for lowly service so wrote the following about the issue of applying super-power elements to low grade service: "These are the essential elements in locomotive design which produce power output at speed with economical performance. Objection may be raised that such provisions are not warrented in the class of service to which secondary locomotives are generally used and that full advantage cannot be taken of these power producing elements. The answer is that they are equally as useful in promoting economical operation as in producing high power output. And, moreover, we believe it will be found that such characteristics are highly desirable in a general service locomotive." Unfortunately, the article appeared only months before the Great Depession reduced the need for locomotives and made it difficult for most railroads to finance modern locomotives. Remember that the Illinois Central did convert an A-1 2-8-4 into a freight Hudson in 1937 -- not exactly what Woodard had in mind but interesting nontheless.
LIMA'S WOODARD ANSWERS THE QUESTION
Purely by coincidence I was paging through some old Railway Age magazines and found an article by W.E. Woodard, Vice President, Lima Locomotive Works, the man who designed the famous A-1 2-8-4 and is credited with introducing "super-power" locomotives. In the article he answers the question originally posed in the Forum, that is, was the Allegheny wasted by often being used on slow coal trains rather than in service where its high horsepower could be better applied.
The article is titled MODERN LOCOMOTIVES FOR SECONDARY SEVICE, and appeared in the April 20, 1929 issue complete with several diagrams, charts and tables (Abstracted from a paper presented to a professional group). In the article Woodard advocated using modern super-power specifically designed for branch line or secondary line service rather than relying on old, outdated power dispalced from main line service.
Woodard realized that many would scoff at the idea of buying a super-power locomotive for lowly service so wrote the following about the issue of applying super-power elements to low grade service:
"These are the essential elements in locomotive design which produce power output at speed with economical performance. Objection may be raised that such provisions are not warrented in the class of service to which secondary locomotives are generally used and that full advantage cannot be taken of these power producing elements. The answer is that they are equally as useful in promoting economical operation as in producing high power output. And, moreover, we believe it will be found that such characteristics are highly desirable in a general service locomotive."
Unfortunately, the article appeared only months before the Great Depession reduced the need for locomotives and made it difficult for most railroads to finance modern locomotives. Remember that the Illinois Central did convert an A-1 2-8-4 into a freight Hudson in 1937 -- not exactly what Woodard had in mind but interesting nontheless.
Interestingly, both Illinois Central and Canadian Pacific took Woodward’s advice - sort of.
IC converted older Pacifics to freight service with lower drivers.
CP built new G5 Pacifics specifically for branch line service in the 1940s.
CP also built new G3 Pacifics for dual purpose usage in the 1940s, albeit primarily for main line usage, but intended to be both freight and passenger haulers nonetheless.
Paul Milenkovic Plate 126 shows a 1923 ALCo 2-8-2 of unspecified railroad with the fire box extending over the last driver.
Plate 126 shows a 1923 ALCo 2-8-2 of unspecified railroad with the fire box extending over the last driver.
It's noted under the photo in Bruce's book that the locomotive was built for stock (without a buyer in mind). It looks a lot like a typical larger logging locomotive. Here's another:
I'll note that, in both photos, the firebox is not ABOVE the drivers, but BETWEEN the drivers.
Also of note is that, in both photos, the trailing truck axle and the lead truck axle are both about the same distance from the drivers. The trailing truck wheels are actually BEHIND the firebox. For weight bearing purposes, this was not necessary. But I suspect it came in handy when backing up, which these locomotives did quite a bit.
I do not consider these logging-type locomotives as germane to the discussion.
The 4-12-2, though, certainly is. I thought perhaps the 4-10-2's might also be in the club, but only one is: Baldwin 60000. Here's an interesting photo illustrating that:
and here's one that's perhaps a bit more flattering:
Ed
Unfortunately, the article appeared only months before the Great Depession reduced the need for locomotives and made it difficult for most railroads to finance modern locomotives. Remember that the Illinois Central did convert an A-1 2-8-4 into a freight Hudson in 1937 -- not exactly what Woodard had in mind but interesting nonetheless.
Paul, just speaking from experience the somewhat archaic writing styles of the 19th Century (and 18th Century for that matter) does take a bit of getting used to, but they're not bad once you get used to them. The thing is to slow down a bit so various bits of the writing don't act like visual speed-bumps.
And of course, some people could write better than others, that's always been the case. Despite their abilities and education not everone was a Charles Dickens, or a Mark Twain for that matter.
I've got a reprint of an 1889 book called "The American Railway," an anthology of various articles by various authors, and some are certainly better than others.
7j43k Are/where there any steam locomotives with trailing trucks, excepting articulateds, that had the firebox partially over the drivers? Ed
Are/where there any steam locomotives with trailing trucks, excepting articulateds, that had the firebox partially over the drivers?
Um, the Union Pacific 4-12-2 "Nines"?
That locomotive is Plate 62 in Alfred Bruce "The Steam Locomotive in America."
Bruce's book has a survey of wheel arrangements, rigid-frame and articulated, that goes into design trades in firebox placement. On p 328 describing the 4-6-6-4 Challenger type, "the grates were generally blocked off at the rear of the throat to provide clearance for the rear drivers as developed on the three-cylinder (4-12-2)-type engines."
So 2 and 4-wheel trailing trucks were indeed used in a complicated compromise in firebox height and grate area when a large firebox had to extend forward from the trailing truck to partway over the drivers.
By the way, Alfred Bruce "The Steam Locomotive in America" is a fun, easy-to-read book with detailed text along with a supporting pictoral section on 20th century steam. I recommend it.
Overmod had also suggested Angus Sinclair, "Development of the Locomotive Engine." That book concentrates on early, 19th century steam. Now I have been told that a lot of the problems that the advanced 20th century designs tried to solve with varying degrees of success were known to 19th century locomotive design engineers. Sinclair's book isn't as "accessible" to me in its writing. Maybe I need to just read it on its own terms to figure out what it is trying to say? Are there parts I should read first?
7j43kOne could speculate that the square footage of lost surface area in the firebox caused by raising the bottom (from the 2-6-6-6's height to that of a Challenger) could have been made up for by lengthening the grates and/or the combustion chamber. I brought the point up originally because of hearing how adding a trailing truck would allow the firebox bottom to drop down, enlarging the firebox. And yet most of articulateds WITH trailing trucks did not have the firebox bottom lowered.
Ed, it doesn't work that way. There's some gain from extending the grate (if you can fire it effectively, something the Big Boys 'cheated' a bit to do) but it's not nearly the same as the advantage from greater rise from mudring to crown -- the same thing that makes narrow-firebox engines like the French 240P steam so remarkably well.
Challengers are a kludge of sorts at the back end, not realizing as much gain from the portion of the firebox that may be over the trailing truck (it is if anything a bit higher than the part over the drivers as the grate has to slope forward to feed coal properly as it burns down). Lima made a great deal of the advantage from deep fireboxes 'behind' the drivers, just as Beyer-Peacock made much of the deep fireboxes possible in a Garratt. These are important considerations.
Now, if you want a four-wheel lead truck (for stability or other reasons associated with higher road speed) with two Mallet-style engines, the overall length with a full deep firebox would be considerably longer than the Challenger type; the practical length of the convection section at practical aspect ratio will still be little more than 20', and the lion's share of the substantial mass of the larger firebox and circulation will have to be carried on the trailing truck - hence the three axles in late Lima designs. About the longest practical arrangement you can have is the 'stretched 4-10-4' that was the Q2; beyond that, you're better off with a good 2-wheel truck as on the AMC Berks (and, for different prioritized reason, the L&N Big Emmas).
The Challenger (and Big Boy) is more like an extended version of the 2-8-8-2 idea: the boiler rides entirely above the drivers, and the trucks on either end are optimized for relatively short length given desired overall axle loading numbers.
One reason the Cunningham circulator is so effective is that it increases effective circulation pattern in the water legs in these large, deep fireboxes with multiple syphons or central circulators. Much of the advantage of the deep box is in better natural circulation and steam-separation without DNB in the radiant-uptake areas, and better defined circulation improves this still further.
Best of all, of course, is a LaMont-style setup with defined fast circulation through waterwall tube construction (the feedwater going through about 6x the mass flow of delivered steam). The 'catch'is how the tubes are arranged in a locomotive-style firebox arrangement...
kgbw49 No doubt the massive and deep firebox on the 1600s behind the drivers was a major factor in their horsepower development.
No doubt the massive and deep firebox on the 1600s behind the drivers was a major factor in their horsepower development.
Mayybeeee....
One could speculate that the square footage of lost surface area in the firebox caused by raising the bottom (from the 2-6-6-6's height to that of a Challenger) could have been made up for by lengthening the grates and/or the combustion chamber.
I brought the point up originally because of hearing how adding a trailing truck would allow the firebox bottom to drop down, enlarging the firebox. And yet most of articulateds WITH trailing trucks did not have the firebox bottom lowered.
It struck me that most articulateds with trailing trucks did not take advantage of the common claim that it allowed a larger firebox. The Allegheny and the 2-6-6-4's did.
7j43k Well, yeah. I figured you guys would come up with some more. Still, it's interesting that there's this difference. Ed
Well, yeah. I figured you guys would come up with some more.
Still, it's interesting that there's this difference.
It would have been interesting to see how one of these would have performed on Oris’ and Mantis‘ C&O “cousin” Nickel Plate Road in High Speed Service, but I suppose every siding between Chicago and Buffalo would have had to been extended to handle at least 1.5 times the train lengths handled by the Berkshires and every turntable enlarged.
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