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Francis Webb,good or bad?

Discussion in 'Steam Traction' started by Hermod, Mar 22, 2020.

  1. johnofwessex

    johnofwessex Resident of Nat Pres

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    While they were rare on the S&D, there is a story of a Compound making a rather disappointing getaway from Bournemouth West until the fireman, ex Saltley showed the driver what to do and away it went
     
  2. andrewshimmin

    andrewshimmin Well-Known Member

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    Hi,
    There were quite a few other Webb compounds, including 4-2-2-0s for the Argentine Western and the Paulista in Brazil, a couple for India (one of which you mention), a Austrian example, one for the Pennsylvania Railroad, and a 2'6'' gauge tank engine for the Antofagasta Bolivia.


    Sent from my Pixel 3a using Tapatalk
     
  3. andrewshimmin

    andrewshimmin Well-Known Member

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    See attached article on overseas Webb locos
     

    Attached Files:

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  4. bluetrain

    bluetrain Well-Known Member

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    Thank-you for the compliment, but I have to pass it on to Mr Ahrons and Mr van Riemsdijk, who provided most of the material for my post (with support from English & German Wikipedia).

    According to Ahrons, the Webb 3-cylinder engines had:
    "An arrangement whereby steam direct from the boiler could be admitted to the low-pressure cylinder. It does not appear that this valve was provided for the usual purpose of helping to start the engine, though thee is no doubt that the drivers frequently tried to use it to that end. Mr Webb stated that it was useful for warming up the cylinder. It was a "two-edged tool", the use of which frequently choked the receiver."

    Half-way through the construction of the 40 Dreadnought class:
    "It was found necessary to improve the starting of the engines by the addition of a by-pass valve in the receiver pipe to allow the exhaust from the high-pressure cylinders to pass directly to the blast pipe, and relieve the back pressure on the high-pressure pistons. This valve, which was introduced in 1886, was under the control of the driver."

    Ahrons notes that Thomas Worsdell hit a similar problem with the first of his 2-cylinder compounds for the Great Eastern. Worsdell's solution was "an intercepting flap valve worked from the footplate was placed in the receiver pipe, and was closed by the driver before the starting valve (admitting air to LP cylinder) was opened. As the engine moved, the first exhaust from the HP cylinder automatically opened the valve, and allowed this steam to pass directly to the LP cylinder". Worsdell went on to apply the same solution on his later North Eastern engines.

    After some lengthy and complex discussion, Ahrons judges:
    Worsdell's compound engines were considerably simpler and cheaper to construct than Webb's three-cylinder type and, within the writer's experience, their performances on the road were more reliable."


    Yes, I was surprised to see that the wheel spacing and firebox layout changed completely from the Bill Bailey to the Experiment /POW / 19-inch Goods (small-wheeled version of Experiment). A fresh set of problems for the firemen, but they somehow learnt to cope.
    I think you can see the Whale Precursors as either simplified and slightly-enlarged Alfreds or as greatly enlarged Jumbos. Both views are valid.

    If you are interested in compound engines, then you will be able to find much material on the internet, following links to wherever you want to go. There is also plenty of stuff on the LNWR and Francis Webb, but here are a couple of Wikipedia starter pages on compounding:

    https://en.wikipedia.org/wiki/Compound_engine
    https://en.wikipedia.org/wiki/Compound_locomotives


    Ahrons says that the receiver capacity of the "Dreadnought" class was 1.58 times that of the two HP cylinders. But without knowing figures for any other types, how does one assess if that is small or big?

    As regards trying to thrash a compound, there is as you say the risk of constipating the receiver. Another factor for the Webb 3-cylinder types is that, with only a single LP cylinder, there are only 2 exhaust beats per revolution, not 4 as for a "normal" engine. So a more uneven draught on the fire. In that respect, the situation is the same as for a 2-cylinder compound - and 2-cylinder compounds could apparently be notorious fire-throwers. Welcome perhaps to line-side photographers who like lots of noise and pyrotechnics?
     
  5. Dag Bonnedal

    Dag Bonnedal New Member

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    As compounds are relatively rare breed in the UK, it might be worth mentioning a few practical details.
    As the expansion is divided between two stages, the expansion is smaller in each one, i.e. you always drive them with long cut off. Typically around 40%.
    If you look at the working diagram for the steam in the cylinder you can see the the power output difference between the work done at 40% and maximum cut off is rather small. While with a simple expansion engine the working diagram at minimum cut off is more like a slim banana. The work done and also the steam consumed is way much lower than at long cut offs.
    That is the reason you can thrash a simple by increasing the cut off but a compound is built to do one job at its designed cut off and does it well at its designed power output. But is not as versatile at doing alls sorts of jobs.
    The fundamental reason for the efficiency of compounds is that the temperature difference between the inlet and outlet steam is lower than for a simple expansion, Thus the cyclic heating and cooling of the cylinder walls, piston etc. is smaller for a compound.
    This cyclic heat loss is specially pronounced at low speed and this is the reason for compounds to be very good at slogging at long grades.
    While the expansion of the steam in the low pressure cylinder gives it big volume and to be efficient at high speed the steam passages and valve ports have to be well streamlined and generous. This was often the Achilles heel of compounds, and it was only in the 1930-ies that Chapelon really demonstrated that it was possible to build compounds with internal streamlining and also high efficiency at high speeds.
    If you have a compound loco with separate control of the cut off for the high and low pressure stages, like the Webb locos with slip eccentric for the low pressure or the French engines with separate reversers for the stages, you might get a surprise. If you increase the cut off of the HP machinery, the receiver pressure increases and thus the power of the HP machinery actually goes down! It is only the output power of the LP machinery that increases. Maybe a bit counter-intuitive.
     
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  6. Hermod

    Hermod Member

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    It can be visualised and I am working on it..
    Use A/B 0-8-0 compound drawings from (1893-1901) .
    Remove the front coupled axle and put a boggie on.
    Take the remaining six drivers 4 feet 6 away from their shafts and put on some redundant 5 feet 2.

    It is now 1903 and result is a Bill Bailey.
    Align the transparent drawings so that the two crank axles are coincident and the aft ends will be indentical within inches.

    In comes a new broom wanting to show how sharp he is.
    Whale knows that a two cylinder simple reving as fast as a Bill Bailey is a no-no so he puts 6 feet 2 drivers on and has to move the last two coupled shafts rearward.
    Try again to compare the Experiments to Bill Baileys using crank centre as zero point.
     
    Last edited: Apr 4, 2020
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  7. LMS2968

    LMS2968 Part of the furniture

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    Thank you, your last paragraph confirms my theory! As to compounds being better at low speeds, George Hughes (L&YR, and one of Frank Webb's premium apprentices) also tried compounding but stated that they were suitable for goods engines only, thereby differing from his mentor.
     
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  8. Hermod

    Hermod Member

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    For Whale it was not a question of compound or simple but number of pistons and driver diameter.
    In Germany it was decreed that two cylinder locomotives should not exced 5 rev per second .
    3 and 4 cylindered was allowed 6 rev per second.
    Bill Baileys were fourcylndered and six rev per second with five feet drivers give same practical max speed as Experiments with six feet drivers doing five rev per second
     
    Last edited: Apr 4, 2020
  9. 8126

    8126 Member

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    I was going to ask about the compound Hughes Dreadnought, which seems by all accounts to have been fairly successful, but I see it was converted after he retired from the LMS. Was that part of the development work for the Fowler compound Pacific that never was, or did Hughes have any hand in it?
     
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  10. LMS2968

    LMS2968 Part of the furniture

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    I believe it was the test bed for Fowler's four-cylinder Compound. and yes, it seems to have been popular enough, although I don't know any of the technical details. George Hughes wasn't involved.
     
  11. bluetrain

    bluetrain Well-Known Member

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    Thank-you for an interesting read. Your library is more extensive than mine!
    These overseas purchases of Webb 3-cylinder compounds all seem to have been for one or two engines, except for the Oudh & Rohilkund who boldly acquired a batch of 10. It looks like some locos were in use for only a short time, others hanging around for 10 or 20 years until (presumably) their boilers wore out. None of the overseas customers built or purchased any more, obviously concluding that the Webb 3-cylinder system was a dead-end. These particular exports must have caused some denting of British engineering's international reputation.
    I don't think Webb can be criticised for giving a prolonged trial to his 3-cylinder system, but 15 years (1882-97) was a bit long. If he had moved over to his 4-cylinder model around 1890, he might have had time to iron-out that system's wrinkles before the mid-1890s, when train weights began to greatly increase and the LNWR had to resort to widespread double-heading.

    Meanwhile, 2-cylinder compounds on the Worsdell/ von Borries and similar systems (with varying starting mechanisms but same basic layout) were spreading in the late 19th century to almost every corner of the planet, with many thousands being built in some countries. It seems appropriate that, while the last Webb 3-cylinder engine was scrapped in 1912, "Aerolite" has a place in the National Railway Museum.


    Well spotted! The coupled axles of the Bill Bailey were indeed in exactly the same positions as the 2nd/3rd/4th axles of the 0-8-0s. So as you say, looks like Webb developed the Bill Bailey by replacing the 0-8-0 front axle with a bogie and changing the wheel size. The Bill Bailey boiler appears to be the same type as used on the Class B 4-cylinder compound 0-8-0 (4ft 8in /1.42m outside diameter).

    The 0-8-0s were slow-speed goods engines and both the compound and simple 0-8-0s appear to have been successful in that role. The Bill Bailey was intended to go a little faster, but acquired a reputation for not wanting to go anywhere quickly!
     
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  12. Hermod

    Hermod Member

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    Bill Baileys had cylinders and boiler common with class B 0-8-0s according to Talbot.
    Let us guess that crankshaft,Joy valve gear and conrods were same also.
    It will be difficult to falsify the theory that Experiments were sligthly enlarged Bill Baileys with inside high pressure cylinders only and not enlarged Jumbo 2-4-0s.
    We need drawings.
    Where can mr Talbot have got the very well reproduced general arrangement drawings for his books?


    What sources for Bill Bailey bashing and were they big boys with watches?
    BB had ca 1600 mm drivers and Prussian S7(Hanover) had 2000.Cylinder layout almost identical and the S7 was timed by grown up prussian officials running 143km/h on level track.
     
    Last edited: Apr 5, 2020
  13. bluetrain

    bluetrain Well-Known Member

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    Mr Talbot's drawings will have come from the archives of the LNWR/LMS Locomotive Department at Crewe Works. I believe that these are now held by the National Railway Museum at York.

    https://www.railwaymuseum.org.uk/research-and-archive
    https://www.railwaymuseum.org.uk/si...e Locomotive Drawings and Microfilm Lists.pdf

    The Webb 4-6-0 was officially called the "5-foot Compound Goods Engine (4 cylinders)", but more often called the "1400-class". LNWR staff applied the unofficial nick-name "Bill Bailey" from a character in a popular song of the time. The name is also used by a present-day British comedian! The "Bill Bailey" was not an express passenger engine, so I doubt whether it was ever timed by an enthusiast with a stop-watch.
     
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  14. huochemi

    huochemi Part of the furniture

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    Ted lists the source of each image, or where not shown, these were from his own collection. At the time the book was first published (1985), the OPC/BR joint venture was the only easily accessible source of drawings from BR and this is indeed attributed as the source of some. However, there appear to be a number not from this source.

    The OPC list (or an OPC list) is still shown in the NRM drawing archive catalogue list (under O). I don't know to what extent this complements or duplicates the Crewe drawing list. The latter like the OPC lists of old, is still a bit of a lucky (or unlucky) dip as to what you end up with having paid your £25, although last time I ordered some, a helpful member of staff warned me that the catalogue description of one was a bit misleading.
     
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  15. Hermod

    Hermod Member

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  16. MellishR

    MellishR Resident of Nat Pres Friend

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    I'm familiar with the song, but why did that name get attached to that class of locos?
     
  17. LMS2968

    LMS2968 Part of the furniture

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    I understand it was because of the line, "Won't you come home, Bill Bailey?" and the engines' reluctance to keep going.

    I don't vouch for the veracity of this.
     
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  18. huochemi

    huochemi Part of the furniture

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    You complete an order form which you can find at https://www.railwaymuseum.org.uk/research-and-archive/further-resources/copying-and-copyright under Engineering Drawings. The copies of microfilmed drawings are rather cheaper than scans of the original drawing, at GBP7.50 for a soft copy (v. GBP27). I do suggest you spend some time studying the catalogue and trying to work out whether the drawing(s) is the one you want, as the descriptions are not always helpful or intuitive.
     
  19. Hermod

    Hermod Member

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    Bad engineering or sloppy manufacture?
     
  20. Hermod

    Hermod Member

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    That opens up a wonderfull goldmine of material for my forthcoming book :

    Save Webb from Whale.

    Thank You very much
     
    Last edited: Apr 6, 2020

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