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35011 General Steam Navigation

Discussion in 'Steam Traction' started by GSN, May 15, 2015.

  1. misspentyouth62

    misspentyouth62 Well-Known Member

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    I visited the Swindon & Cricklade 60th Anniversary Gala on Friday and had the first opportunity in many years to paw over the 'remains' of GSN. This is the view of the rebuilt inside cylinder viewing from the front between the frames.
     
  2. daveb

    daveb Member

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    For any N gauge modellers out there, the General Steam Navigation wagons are currently available in N gauge, available from both the 35011 and Medway Queen PS websites. I picked a couple up at TINGS at the weekend.
     
  3. siquelme

    siquelme Member

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  4. siquelme

    siquelme Member

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    Our trailing truck has arrived safely at the North Norfolk Railway where work will start on its restoration in the coming weeks. You can help support its restoration by becoming part of our Trailing Truck Transformers funding group. By joining this exclusive group you'll be directly helping our efforts to restore the first main component of General Steam Navigation back to mainline standard. You can find out more on our website
    https://35011gsn.co.uk/funding-campaigns/trailing-truck-club.html

    Thank you
    Photo courtesy of Andrew Rothe
     

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  5. Allegheny

    Allegheny Member

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    From what I understand of "General Steam Navigation", some of Bulleid's more novel ideas are being tweaked with the benefit of hindsight and modern engineering, so it will have the same relationship to the original MN as the new P2 will have to the original.

    To catch up on some other points that have been raised recently on this thread, regarding track curvature, didn't the NYMR have some problems operating an LNER pacific through to Whitby?

    On the modern railway one of the limitations of steam traction is acceleration. Would an 8-coupled locomotive have an advantage over a 6-coupled in this respect?
     
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  6. Spamcan81

    Spamcan81 Nat Pres stalwart

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    IIRC 60007 went there once and after that it was a case of "never again".
     
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  7. 30854

    30854 Resident of Nat Pres

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    GSN Is a fascinating project. Though I saw mention of design modifications, have any specifics been detailed? Would one such perhaps involve amending the design of the crank axle, in similar fashion to P2 2007? Though I get the point about the resemblance of the finished product to the originals, there's rather more metal in this one which left Eastleigh in the 1940s than either A1SLT loco started with.

    The question of acceleration is an interesting one, as during 34092's Giesl fitted mainline stint, among comments which sticks with me were "accelerating the Scarborough Spa Express like an electric" and a BR manager quoted as saying he could do with a dozen such locos on his patch. Whether the latter was said with the train in motion, or a few sherbets later is a different question entirely!

    I can't recall if the outline diagram of the 8 coupled proposal (the 'Merchant Navy' tag not then coined and pre the Civil Engineer's insistence on a K-H leading truck) I saw in HAVB's biography of his father's work indicated weight distribution. Though you have to suppose a greater adhesive weight would've tended to reduce slipping, much still depends on the power (and more consistent torque characteristics) of the three cylindered engine. Here, the crank axle failures on the original MNs and P2s loom large.

    One thing which crossed my mind, if GSN is to go mainline at some point, concerned water capacity. A1SLT reduced the coal capacity of the LNER (four axle) tender to increase water supplies. In days of yore, the longest truly non-stop MN working was Waterloo to Bournemouth. If memory serves, that's 108 miles. The Devon Belle* despite the first passenger station stop being Exeter, involved an engine change at Wilton.

    If there's one thing even a ardent fan of Mr.Bulleid's machines (Hello!) would have to concede, it's that they weren't best noted for low coal consumption. How much scope will the GSN have to play with the coal/water ratio? I'm going to go out on a limb here, but I'm guessing a bogie tender design to MN outline wouldn't find much favour. Ditto, s'pose, Mr.Pegler's solution of a second water tender. That leaves the auxiliary tank in the leading carriage, developed during the preservation era. What a shame Bulleid's suggestion of a 15" gauge edition of the MN for the RH&DR was a non-starter .... that would've provided a half way credible excuse precedent for a bogie tender!

    *Edited to reflect correction (with thanks )from @Maunsell907
     
    Last edited: Oct 18, 2021
  8. torgormaig

    torgormaig Part of the furniture Friend

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    Were they particularly heavy on coal? Sure they will burn any ammount that they are fed but a good fireman will soon learn to be economical in his firing, if only to make life easy for himself. Remember that Bulleid tenders only carried 5 tons of coal whereas other Pacifics often had a capacity of 9 -10 tons. I suspect that if they were such coal guzzlers the later locos would have had a larger coal capacity. But I have to say this is only a hunch - I'm no expert in this (or any) field.

    Peter
     
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  9. Maunsell907

    Maunsell907 Well-Known Member

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    A thoughtful posting, thank you.

    A couple of nit picking details. The Atlantic Coast Express stopped at Salisbury (83.7 miles from Waterloo) where
    water was taken. The ‘Devon Belle’ changed locos at Wilton (2.8 miles further ). Whilst non stop running to
    Bournemouth was regular ( Bournemouth Limited ) pre WWII; it was rare post WWII ( the ‘Belle’ stopped at
    Southampton as it had pre WWII, there was no ‘Limited’.)There were some Summer Saturday trains that
    ran Bournemouth non stop, but they were a rarity.

    The best indication of the original MN’s fuel efficiency I think are the 1948 locomotive exchanges.
    As a Class comparator they offer little, as individual footplate crews adopted different approaches, as an
    oversimplification the SR crews set out to prove what they could do, the Duchess was driven overall
    ‘easily’ ( the schedules demanded nothing more )

    However: lb of coal per mile for the MN were per region WR 48.02, ER 49.41, LM 50.66, SR 50.65.
    The highest of the five classes in the passenger group.

    (by comparison the A4 gave the lowest figures Ie 42.45, 39.08, 41.25 & 45.57, in all bar the last the
    lowest of all the passenger locos. Again driving characteristics were at play i.e the A4 was driven,
    based on the logs available, hardest on the SR and WR, the splendid start with 525 tons east from
    Taunton for instance, Castle Cary passed within even time. )

    Conversely when evaporation figures are considered the MN in terms of lbs water evaporated per lb
    of coal the MN was only beaten by the Duchess.
    Average evaporation rates lb water/coal Duchess 8.67, MN 8.45, King, 8.07, A4 7.92, Royal Scot 7.70.
    ( remembering the MN was driven harder than the Duchess and therefore probably at a similar
    or perhaps with a superior boiler efficiency )
    i.e confirms what we probably all know, under Bulleid’s aegis an efficient boiler mated with
    an inconsistent front end.

    If memory serves me right the first ten loco had 5000 gallon tenders, the next ten 5,150 and
    the last ten 6,000. Subsequently some ( if not all. ) the earlier ones were modified and of course
    in later years there were various tender swaps etc. However if we assume 60lb coal per
    mile ( allowing for the fact that present main line running is hard, often due to pathing
    considerations ) then ( assuming evap of 8lbs water per 1lb coal ) then c.50 gallons per
    mile. If 6000 gallon tender and we assume 4,000 gallon used 80 miles.

    My feeling is many tours have water stops at this frequency ( 5000 gallons then 100
    miles ) and if a ‘Tyseley type 2000 gallon extra supply then 120 miles ?

    Sadly I think we are still some years away.

    Michael Rowe

    p.s based on 7 ton coal capacity and 60lb/mile c.250 miles
     
    Last edited: Oct 18, 2021
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  10. Allegheny

    Allegheny Member

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    I think devices such as the chain driven valve gear, and the exhaust system are being looked at, as Jos Koopmans observed in his book, imposes a higher back pressure on the pistons than could be achieved by other designs.
     
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  11. 30854

    30854 Resident of Nat Pres

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    I don't pretend to understand more than the very basics of the chain drive .... and then, probably none too well. The front end considerations, I'm slightly more at home with. My understanding of the Giesl ejector (as fitted to 34064 and 34092) being that while it worked when correctly aligned and maintained, the presence of moving parts in so hostile an environment as a locomotive smokebox is something to be avoided if humanly possible. From an operation point of view, so is addition of components unfamiliar to those not specifically trained in their use.

    The Bullied Lamaître application, as originally fitted, certainly seemed conducive to steam production, but I can't help but wonder (and how best to put this?) what percentage of coal so laboriously shovelled through the firebox doors actually performed the task it was so expensively provided to perform? To what extent inclusion of the Porta ejector arrangements would be possible, again I don't know, but if I'm reading the runes correctly, the MN smokebox looks a lot more conducive to such an arrangement than the W&L Beyer Peacocks, where LDP's principals were applied to benefit.

    Whether a gas producing grate would be either a sensible or viable feature to investigate, I don't know, but one question there (beyond the obvious "can it be retrofitted to an existing boiler?") would have to concern the likely effects on the thermic syphons. Perhaps I've misunderstood, but it appears the weak point of those is the scouring effect of particulates on the obtuse angle exposed within the firebox. If provision were an option, would the characteristics of a GP firebed improve or worsen the situation?
     
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  12. Maunsell907

    Maunsell907 Well-Known Member

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    I thought the concept was to restore/rebuild ( retrospective ) GSN to 1940s condition.

    If the concept is to have a ‘modern’ loco within an ‘air casing’ then perhaps it should be judged against Mr Jarvis’s rebuilt MN.
    I think if that is the comparator then ‘Porta type’ mods might seem less appealing. I empathise with Cox, that many
    modifications eg.‘Franco Crosti’ ‘Giesl’, fluidised beds etc are less appealing when applied to an existing well
    designed machine.

    I do not believe it was just NIVH. Michael Rowe
     
    Last edited: Oct 18, 2021
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  13. Allegheny

    Allegheny Member

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    Discussion of GSN would be better on this thread.
    35011 General Steam Navigation | National Preservation (national-preservation.com)
     
  14. johnofwessex

    johnofwessex Part of the furniture

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    So what was Bulleids proposal for the RHDR & how much detail work was done on it?
     
  15. 30854

    30854 Resident of Nat Pres

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    I believe it was no more than an 'off the cuff' remark by Bulleid, of the "What this line could use ...." variety, at either one of the postwar RH&D 'reopening ceremonies', or an invitation event to mark the return of one of their locos overhauled at Ashford (No.5 Hercules IIRC).

    Somehow, after No.8 Hurricane went and tied it's inside motion into knots back in the 30s, the suggestion of any new 3-cyl loco would've been a complete non-starter, even had postwar currency restrictions not prevented Howey accessing his Australian income stream, as in the pre-war era. Amusingly, Howey's 'revenge' on his former favourite loco was to temporarily rename it Bluebottle!

    Even had they wanted to, the Southern were hardly in any position to fork out for such a project.
     
  16. Jamessquared

    Jamessquared Nat Pres stalwart

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    Are you sure about that?

    If you take the chain drive out, you aren’t doing what the project claims, i.e. return to an original condition MN. You are also setting yourself up for a ton of expensive design and certification problems if you choose to build something that is neither original, nor Jarvis (ie three sets of full sized Walschaerts valve gear).

    I think the issues with the chain-driven valve gear were largely related to maintenance, something that is to a degree avoided in an occasional use loco in current conditions. Likewise the actual Achilles heal of the first Merchant Navies - the steam reverser - suffered from some poor design (which the SR and BR largely overcame) and poor accessibility for maintenance (which was changed for the better on later locos). A screw reverser would give finer control, but at that point it is no longer an original MN.

    Tom
     
    Last edited: Oct 18, 2021
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  17. 30854

    30854 Resident of Nat Pres

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    Rather begs the same question of any modification (other than for compliance/safety reasons). I guess the closest comparison would have to be with 71000, in regard of any changes beyond correcting clear construction errors. Where does that leave the sort of mods made which a turn at Rugby for Duke of Gloucester might, or might not have suggested?

    On the other hand, given Bulleid's well known penchant for innovation on the hoof .....
     
  18. Hirn

    Hirn Member

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    Yes, in two ways. There is a direct relationship between the weight on the rail and the amount of power the grip of the wheels will transmit - “adhesive weight” this is very well established scientifically, originally before Puffing Billy was built. Also practically: the weather may lessen the adhesion - heavy dew is worse than a downpour, and oil/grease may get on the rail head - there is a notorious flange lubricator near the top of Shap, the effect is better reliability which helps running specials on the main line quite comparably to better acceleration.
    Two different wins.
     
    Last edited: Oct 19, 2021 at 11:07 AM
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  19. Allegheny

    Allegheny Member

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    My understanding was that the design of the chain driven valvegear would be re-visited to improve the reliability, reduce oil leaks etc. possibly using modern materials, seals etc, and eliminating any other flaws, instead of replicating what was done in the 1940s. I didn't mean it would be eliminated altogether.
    This would also apply to the steam reverser.
     
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  20. Jamessquared

    Jamessquared Nat Pres stalwart

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    Ah thanks, I’d mid read you then!

    Tom
     
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