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GWR 111 "The Great Bear" and Surrounding Controversies

Discussion in 'Steam Traction' started by Osmium, Oct 24, 2021.

  1. Jimc

    Jimc Part of the furniture

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    I've seen claims about numerology and so on, but it seems far fetched. Churchwards other prototypes included 97, 98, 99, 100, 101, 102, 103, 104 and 115. All those numbers had been used before and 110-114 were 1860s 2-4-0s withdrawn between 1904 and 1914. I don't doubt that 111 was chosen because it was distinctive but I don't see any need for any more than that.

    Incidentally there's a photo in existence that shows the 2-4-0 111 buffer to buffer with the Bear. As the Bear was completed in 1908 and the 2-4-0 withdrawn in 1904 there has to be a suspicion that the 2-4-0 is not the real 111, but one of her sisters with a number plate swap!

    https://www.steampicturelibrary.com...1-great-bear-111-2-4-0-locomotive-413723.html
     
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  2. K14

    K14 Member

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    The photo shows TGB with top-feed, so likely to be from its 1913 refit. That might narrow the field for the real identity of the 2-4-0.
     
  3. Osmium

    Osmium New Member

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    It seems this discussion has died down but I have a new proposition for discussion; if you could improve no. 111, what actions would you take? Would you even consider the path of having a standard pacific when the contemporary Stars and Saints were phenomenal on their assigned trains?

    Like I said earlier in the topic, I think 111's largest failing is the 23-foot long boiler tubes which are much too excessive for a locomotive this size. Having tubes that long for a boiler with the heating surface it had (3400.81 sq ft excluding superheater) was just asking for trouble. Most American locomotives from the time had boilers with much larger heating surfaces with tubes shorter than this. Swindon could have gotten much more out of the locomotive if they kept the fat boiler but significantly shortened the tubes, as a fat short boiler is a much better steam producer than a long thin one, with large savings to weight as well. This is partly why the Beyer Garratts were so successful since their boilers were extremely well proportioned, and why the Gresley H4 was able to have a boiler with a good-steaming boiler with a 6-foot diameter producing high power at high speed while keeping the weight under 72 tons.

    The boiler barrel probably could have been shortened overall, but particularly the tubes should have been shortened. Some American books on locomotive boilers discussed how the majority of heat produced was in the first 10-11 feet of flues, with the percent of heat absorbed rapidly dropping past that length. This is not literally to say that locomotive boilers should only be 10-11 feet long, but that the longer the tubes are, the less they contribute to producing steam and eventually essentially become dead weight, which is what happened in no. 111. Some tests with different locomotives showed that the heat production past the first 10 feet or so of tubes is often less than 5% of the total heat produced, but this is subject to many variables such as rate of gas flow and firebox temperatures. It's said in these books that after a length to effective diameter ratio of 70-75 times, the amount of heat taken up rapidly lowers, which is about 14-15 feet for most locomotives, but if a higher draft is in effect, the length can be made longer, which is why American locomotives with extremely high drafts usually had tube lengths around 20 ft. I'm not sure what the gas flow rate was for 111 (if anyone has data please share it), but it almost certainly wasn't enough to require 23 ft tubes. These studies were made after the construction of no. 111, but the concept of most efficient tube lengths was probably starting to get noticed at the time of construction. Even so, the no. 111 could have been modified after the fact.

    At any rate, the tube length of no. 111 almost certainly should have had tubes 20 feet in length at the very max, probably shorter than that. I think they could have gotten away with 18-foot tubes. A combustion chamber could have been fitted past the shortened tubes. This would have made the boiler considerably lighter as well as more efficient and a better steamer overall.

    There are other numbers of obvious changes like changing the rear axle to an outside bearing truck and the like, but another thing is that I've always felt that the cylinders were undersized for no. 111. This may have been necessary due to the shortcomings of the boiler, but if the boiler and steam circuit were improved, they're letting its potential go to waste with four 15-inch cylinders. They easily could have achieved a starting tractive effort above a Castle and likely a higher pulling power at speed. Maybe superfluous for before WW1, but the GWR essentially could have a properly powerful locomotive that would have given most 1920s-1930s express locomotives a run for their money.
     
    Last edited: Jan 12, 2022
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  4. Spamcan81

    Spamcan81 Nat Pres stalwart

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    The GWR did a very good job of improving 111 when they rebuilt it as a Castle. Job done IMO.
     
  5. Osmium

    Osmium New Member

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    Fair enough response. I suppose that did improve the power to weight ratio considerably :p.
     
  6. 30854

    30854 Resident of Nat Pres

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    Not to mention the route availability! :)
     
  7. Jamessquared

    Jamessquared Nat Pres stalwart

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    What was the state of the art in wide-firebox Pacifics ca. 1900 - 1910? The earliest I’m aware of were the New Zealand Q class of 1901. What would Churchward have known about as prior art?

    Tom
     
  8. 30854

    30854 Resident of Nat Pres

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    Had to do a bit of searching. It seems the Q are reckoned to be the first pacifics. Built by Baldwin apparently, which begs the question what influence they had on US design thinking. The first US pacific is referenced as being in 1902, but built by who and for which line, I can't find at present.

    Was Q class designer A.L. Beattie, an expat Englishman, related to certain other well known loco engineers of that ilk?
     
  9. 242A1

    242A1 Well-Known Member

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    The Missouri Pacific P69 class were built by Alco-Brooks and date from 1902 and they lasted rather well with the last being withdrawn from service in 1953 they had a grate area of 42.4 sq ft, very close to the 41.79 of GWR 111. These were not the first of the type produced in the US since the type is credited with being introduced in 1886 on a double cab "Mother Hubbard" type specially built to burn anthracite tailings.
    So, like so much else in the history of the steam locomotive, matters are not as simple as we might be given to suppose.
     
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  10. GWR4707

    GWR4707 Nat Pres stalwart

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    And speed.
     
  11. Jamessquared

    Jamessquared Nat Pres stalwart

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    I guess what I’m getting at is, if the boiler proportions are wrong, and knowing that Churchward was quite awake to developments elsewhere, especially in the US, how much were such proportions arrived at by trial and error, and how much by valid theory, at that time?

    Tom
     
  12. 30854

    30854 Resident of Nat Pres

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    Aaah, you mean "what portion of locomotive development was empirically determined according to the principles already established by 'ee-triple-emm' methodology?".

    Might another question be why Jones, Churchward and later (honourable mention) Russell* and Urie managed to produce successful six coupled locos (with leading bogie), when Drummond, McIntosh, Coey (GS&W) and later Bowen-Cooke made such a pig's ear of theirs?

    *Yes, I do know the S69 was credited to Holden!
     
  13. LMS2968

    LMS2968 Part of the furniture

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    I don't think I'd class Bowen Cooke's 4-6-0s as pigs' ears. The Prince of Wales was a decent though not exceptional engine while the Claughtons were capable of some excellent performances. Their problems were the Schmidt valve rings causing excessive coal consumption; and some built-in mechanical defects which were less easily remedied, the poor oil delivery system to the trailing boxes defying rectification.
     
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  14. Hunslet589

    Hunslet589 New Member

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    Agreed. Much/most of what Osmium says is fair comment, but the sample of designs proving the point as somewhat small when the Bear was built. Big boilers and wide grates where a hot topic at the time and as has been said before, I believe that The Bear was GJC's attempt to learn more about them first hand. The fact that it needed a pacific chassis to go under it was beside the point as far as he was concerned.
     
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  15. Jimc

    Jimc Part of the furniture

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    In his 1906 paper, large locomotive boilers, Churchward stated that the experience of long tubes was quite satisfactory, especially when the boiler was being worked near its limits, so it clearly wasn't obvious the boiler was wrong on the drawing board. To my mind, with hindsight, and even to an extent with what was known at the time, the problem with the Bear was too much heating surface in too long tubes, and not enough heating surface in the firebox. The obvious resolution for this is a combustion chamber, but Holcroft tells us Churchward vetoed the idea because combustion chambers gave a great deal of trouble on the Krugers. One of Churchwards's rare misjudgements, since what was required was to sort the combustion chamber out.
     
  16. Osmium

    Osmium New Member

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    This is why I explicitly said many of those studies were made after the building of no. 111. Most of the ratios which became standard were established after, but the empirical evidence was already building at the time of no. 111. Caution has to be taken with how much you can blame Churchward or any other CME/superintendent/draughtsman because there was an enormous amount of trial-and-error when it came to building larger locomotives. Many people had to learn the hard way that you can't just extend the boiler of a smaller locomotive and get proportional results. Even so, there were a good number of pacifics running in the US and other countries (South Africa for instance), and none of them had tubes that long. Even if we accept the original no. 111 as a failure due to lack of empirical evidence, it could have been modified for better results. I'm surprised Churchward was so quick to drop interest in wide-firebox development after no. 111 considering the trends in other countries. Many contemporary pacifics, such as the Bavarian S 3/6, the Paris-Orleans 1907 pacifics, and the Belgian type 10 were all huge successes.
     
  17. Jimc

    Jimc Part of the furniture

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    Maybe one should think about need. The superheated Stars with enlarged (Great Bear sized) cylinders were very successful indeed, and post war Churchward was having design work done on the enlarged (Std 7) boiler Star that eventually became the Castle. Churchward also knew that until the weight limits were relaxed a pacific would continue to be problematic. So perhaps it ceased to be developed because it was evident the need for it had passed?
     
  18. Osmium

    Osmium New Member

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    Likely what his results indicated was what the Americans found, that the larger the draft/gas flow rate in the boiler, the more long tubes actually contribute to efficient heat absorption. The problem is that the services no. 111 worked were likely not nearly not hard enough for a strong enough draft for 23-foot tubes. Like I was saying, even many American locomotives which had extremely high drafts compared to elsewhere didn't have tubes that long, usually 20-21 feet being the max.
     
  19. Osmium

    Osmium New Member

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    I'm not sure if the need for a pacific necessarily had ever passed. Sometimes I consider the possibility that a pacific design may have actually been superior to the King design. The axle loading for a pacific design would have almost certainly been lower than the King if appropriate proportions were taken. And as I said, if the tubes were shortened on no. 111 and replaced with a combustion chamber, the weight would have been decreased a good extent. I'm sure you know, but many stokers complained about the extreme difficulty of firing a King with a twelve-foot long grate area with inadequate slopes. Perhaps a pacific with a wider grate area would have been easier to fire and would have been better at steam generation at high speeds (although this depends on the firebox design; long narrow fireboxes worked extraordinarily well in France with the 240 designs being essentially the pinnacle of the narrow firebox principle).
     
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  20. 242A1

    242A1 Well-Known Member

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    The Journal of the Institution of Locomotive Engineers Volume 20 Journal No. 93 Paper 253 is worth glancing through with respect to the thinking and degree of understanding prevalent when it comes to the understanding of A/S ratios in the late 1920s. Quite what existed before this period needs to be uncovered and like many I bemoan the lack of information available to us in the more accessible sources.
     

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