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Super Garratt

Discussion in 'Steam Traction' started by SomeWeeb, Nov 4, 2021.

  1. Bikermike

    Bikermike Member

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    I wonder how much loss you'd get from having two live steam joints on each end? (And would the exhaust from both come back as well?) - either by friction (if steam-tight) or pressure loss (if lack of friction was prioritised).

    And where do you hook up the steam tender to make it a Garamallatet-Sturrock?
     
  2. 30854

    30854 Resident of Nat Pres

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    The FfR have developed high pressure steam joints on their Fairlies considerably in recent years. On the early compound Garrats, I've seen mention that the supply line between high and low pressure cylinders effectively functioned as a receiver too, though with no obvious lagging, it's be doubtful how effective it'd be. Just one reason, I suspect, why compounding fell out of favour with BP.

    It's maybe worth noting that the solitary Garratt built for Russia (the biggest BP ever wrought) found no favour. No specific reasons were given and I've no idea where in the vastness of Russia it was deployed, but losses in the high pressure supply pipe seems a reasonable guess. In the main, Garratts seem to have done better in warmer climes.

    On the exhaust side, I've seen no criticism concerning excessive (or insufficient) back pressure. Pretty much the only comment I can recall concerns the effects of the exhaust pipe's routing on loading gauge (very much an issue with respect to UK examples). If exhaust was a problem with the Fairlie concept, I suspect Blodge would've gone into print by now. Certainly shots of the FfR Fairlies working in cold conditions don't normally show exhaust steam where no exhaust steam should be.

    I honestly don't know if this is anything with potential to be adapted for full-sized locos, but on his 5in gauge 'Leader', Kevan Ayling adopted a modern grade of armoured pressure tubing, needing to 'up' his initial calculations of steam temperature and replace the original tube after it melted .... thereby managing to find one more problem than Bulleid!

    Re: Sturrock steam tenders, the issue I recall mentioned most was the same which cropped up with the later LNER Garratt, i.e. firemen complained they were expected to do two mens' work for one man's pay. Was that an issue with the larger LMS fleet?
     
  3. Jamessquared

    Jamessquared Nat Pres stalwart

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    On that point, I think the crew in Sturrock’s day had just cause, since at that time drivers were, to a much larger extent than later, responsible for their own repairs and maintenance.

    I do also wonder to what extent the boiler was adequately sized to keep up with both engines, it would be interesting to know if anyone has researched that, or how it was intended they would be used.

    Tom
     
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  4. 30854

    30854 Resident of Nat Pres

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    I believe Sturrock had the coal traffic between the pits and Lonon in mind.
     
  5. MellishR

    MellishR Part of the furniture Friend

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    I'm still not sure what you're getting at. The differences between those South African locos and a Fairlie are the single boiler (with two power bogies) and the large overhang of the rigid frame beyond the points where it's supported by the bogies. But you were citing a difference between Fairlie bogies and diesel bogies. The positions of the bogies under a FfR Fairlie seem to me similar to the positions of the bogies under a typical diesel.

    (BTW: Why do we write "Fairlie" with a capital F but not "Diesel" with a capital D?)
     
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  6. 30854

    30854 Resident of Nat Pres

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    Broad brush. I wasn't and I'm not, albeit Fairlie did anticipate the basic geometry of what dangles off a large diesel's superstructure. No more than that. Tell you what, forget I even mentioned diesels .....

    The bogies on a Fairlie (original or 'modified') can't feature any component liable to foul what they're attached to, where the "bogies" on a Garratt are more properly 'units' which perform the addition task of carrying their own bit of superstructure (viz. tanks and bunker).

    .... point 2. I don't know either. Presumably Dr.Diesel patented his invention, but how many diesels feature a patent's name on a shiny brass plate, as does Merddin Emrys? Perhaps it's no more tham Robert Fairlie's contribution to steam locos and the history of the Ffestiniog being so intertwined.
     
  7. jnc

    jnc Part of the furniture

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    Interesting question (one that's of special interest to me because of my involvement with the 'internet/Internet' controversy - although not exactly a parallel, as 'internet' and 'Internet', as originally defined, had different meanings, so changing the capitalization changed the meaning).

    I think 'diesel' lost the capitalization because it is a general concept (ignition by compression of a fuel charge in an internal combustion engine), and became a general term for that concept, and engines which used it; lots and lots of companies have built 'diesel' engines without having any connection to Diesel. I'm not a Fairlie expert, but I have the impression that most 'Fairlie' engines were built by companies with some sort of formal relationship with Fairlie - licenses, etc.

    Noel
     
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  8. Jamessquared

    Jamessquared Nat Pres stalwart

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    Proper nouns lose their "properness" with ubiquity: few people capitalise "thermos" (*) or "hoover" though both were, originally, trade names. I'd suggest the answer to @30854's question tells you much about the relative success of Herr Diesel's concept and Mr Fairlie's ...

    (*) I avoid such confusion by using "Dewar" - as in 'Did you pack a Dewar of coffee, dear?" before any trip out ...

    Tom
     
  9. jnc

    jnc Part of the furniture

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    Right, but 'widely used' (one flavour of 'ubiquitous') is not the same as 'applied to many instances' (which I think is a more accurate description of the cause of loss of capitalization). 'White House' is used all the time, but it's still capitalized (because there's one 'special' one which we want to distinguish). But of course that's not a perfect analogy either, because there's more than one Fairlie.

    Noel
     
  10. Wenlock

    Wenlock Well-Known Member Friend

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    Personally I prefer "vacuum flask", but it is important to pronounce all of the vowels separately. Vac-u-um.

    The same word can also be used for a generic vacuum cleaner, to avoid confusion with a cl50 diesel.
     
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  11. meeee

    meeee Member

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    The receiver pipe between to the two bogies on the K class garratts is certainly lagged in WHR service. Correct valve setting and steam tightness is quite fundamental to making it work. Otherwise the pressure in the receiver is too low and one bogie does all the work. Likewise correct notching up.

    The K class were a solution to a very particular problem. The NEDT was an extremely challenging line through very inhospitable terrain. Curvature was only really suitable for 4 coupled locos. The gradients were very steep. So the line was a slow speed continous slog that lends itself to compounding.

    The 8 ton axle load restricted the size of the boiler too. The huge J class had proved far too big and heavy for the track. So without adding some carrying wheels the Garratt principal of a fat boiler and firebox was a non starter. Maybe he wanted all the weight available for adehision. There were severe limitations to what was possible.

    Still I think we read too much into the design of the K class. It wasn't built to Garrats principle as he saw it. It was built for a particular job for which there were no easy solutions. The fortunes of the railway ended its career long before we could tell if it was any good or not. We forget that the simple Garratts built for Darjeeling which are a similar size were also not all that successful.

    Tim
     
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  12. johnofwessex

    johnofwessex Part of the furniture

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    I cant speak for Mrs @Jamessquared but Domestic Facilities Management's response would sound like a rather over excited Rab C Nesbit liberally peppered with words that would make a stoker blush
     
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  13. 30854

    30854 Resident of Nat Pres

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    Most enlightening. Cheers @meeee. I knew nothing about the nature of the Dundas line, but reading that, wonder if the tramway had looked at other solutions, as what you describe sounds equally suited the Shay or Heisler layout. The requirement you mention also sounds similar to that which kept William Francis gainfully employed here.

    One aspect leading to the option of Garratts, which often goes unmentioned, is the increased power per ton of axle load. In S.Africa, the last class of 3'-6" gauge Garratt, the GO, were effectively a lightweight version of the far better known GMA (or it's mainline flavoured GMA/M variant). Where axle load was less of a limiting factor, monsters like the magnificent SAR GL, EAR 59 and RR 20/20A Classes showed what could be done.

    Not immediately obvious across much of their habitual stamping ground was the capacity of larger wheeled Garratts for 'spirited running'. In Brazil, the 5'-3" gauge 2-6-2+2-6-2 Class R1 locos, first built in 1927 were the first articulated locos scheduled to run at 60mph (with a 500ton train!). There may have been some instability at speed, as after just four years, they were provided with new frames (con rods and other valve gear components), with a front bogie replacing the pony truck. Reclassified R2, they emerged as 'double pacifics', in which form they served until rendered redundant by electrification in 1950.
     
  14. meeee

    meeee Member

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    The first 5 miles was relatively easy, the next 12 had something like 30 curves per mile and 1 in 25 gradients. Speed limits were 12mph on the easy bit and 8mph on the twisty section.

    They tried a huge Hagans flexible wheelbase loco. It was over 40 tons and spread the track. The track was upgraded but it still caused so much wear it was restricted to the easy section around Zeehan. The K class seems to have been more successful, and the railway disposed of the two chunky Sharp Stewart tank engines they also used. At some point they were worn out enough that K1 and 2 were combined to make one good engine. The one that ended up being preserved was actually made up of the bad bits. The good boiler being sold to power a mill.

    Tim
     
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  15. 30854

    30854 Resident of Nat Pres

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    I often wonder about regular workshop practices on the EAR & SAR. Here (UK), spare boilers speeded overhaul schedules on all numerically larger classes. Did the operators of large Garratt fleets treat boilers separately, or were boiler cradle units, ready fitted up, rotated through fleets?

    A comment by Durrant, that whether the largest SAR Garratt class were returned from overhaul as the GMA of GMA/M flavour depended on which was required next out of the box, some changing between those varieties several times during their working lives. That and comments about variations in nominal driving wheel diameters between forward and aft engine units on the EAR suggests a fair amount of interchange between the three discrete units making up class members.

    It rather puts the WHR's almost apologetic 'mix and match' approach to keeping enough NGG16s in the shade!
     
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  16. SomeWeeb

    SomeWeeb New Member

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    I just came up with a dumb idea. Garratt with a Geisel ejector.
     
  17. torgormaig

    torgormaig Part of the furniture Friend

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    You mean like these? 84-4-8 6 6023 6006 6018 Nairobi Shed copy.jpg

    A trio of EAR Class 60 Garratts awaiting their fate, Nairobi shed April '84. Virtually all the EAR's large fleet of modern Garratts were fitted with Giesl Ejectors in later life.

    Peter
     
  18. SomeWeeb

    SomeWeeb New Member

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    I never knew that!
     
  19. pete2hogs

    pete2hogs Member

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    Lovely beasts. so sad.
     
  20. Romsey

    Romsey Well-Known Member

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    Just to cheer you up .... 5924 departing Voi 15 June 1978
    It doesn't seem long ago, but it was 43 years ago.

    Cheers, Neil A984 5924 Voi 15 June 1978.jpg
     

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