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FR & WHR & WHHR News

Discussion in 'Narrow Gauge Railways' started by AndrewT, Jul 17, 2012.

  1. michaelh

    michaelh Well-Known Member

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    Is Lyn superheated?
     
  2. 30854

    30854 Part of the furniture

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    Yep ..... isn't Lyd?
     
  3. 8126

    8126 Member

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    I believe the FR engines are generally fitted with quite a low degree of superheat. I've just checked, and there are 2 flues per barrel for a double Fairlie (except DLG, which I think has more), while Lyd has 8 flues in its single barrel. If you're retrofitting superheat to slide-valved engines, low degree superheat is generally considered sensible, although I suspect in later LNER years quite high-superheat boilers ended up on Ivatt Atlantics which had not received piston valve conversions.

    Lyn, on the other hand, is a piston valve engine and was designed as such from the outset. She has eleven flues, so to a first order approximation will have a considerably higher degree of superheat. This carries through to exhaust temperature. Notched up, this might not make so much difference, but working hard at medium cut-offs and large regulator openings, the exhaust will be a lot less visible. I remember seeing videos of SAR 25NCs working hard in the cold Karoo. The exhaust would be invisible, until it suddenly appeared in a giant plume a few feet above the chimney.

    *Edited to reflect actually taking the time to check my numbers.
     
    Last edited: May 6, 2019
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  4. 30854

    30854 Part of the furniture

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    Many thanks for a comprehensive explanation .... I did originally say it was possibly a daft question! :)

    Thinking back, I do seem to recall a shot of Lyd's front tube plate during construction and recognise your description from that. A quick shuftie at Lyn's construction pages confirmed the degree of superheat applied.

    From various sources concerning it's visit to the FR/WHR t'would appear Lyn's performance has impressed folk all round. It certainly looked the part in all the clips and stills I've seen .... especially (IMHO) as it wasn't spewing the filth beloved of too many photographic types!
     
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  5. Jamessquared

    Jamessquared Nat Pres stalwart

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    Likewise the Brighton Atlantics (H1 - originally saturated and slide valve and H2 - originally superheated and piston valve) which by the end of their lives were all fitted with superheated boilers, with 32 flue tubes (4 rows * 8 flues). I suspect lubricant technology developed considerably between, say, 1910 and 1950; no doubt the two wars and the need for high performance aero engines acted as a spur to innovation in lubricant technology.

    Tom
     
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  6. weltrol

    weltrol Member

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    Looking at recent photos and videos of 'Lyn', the loading gauge seems very close to that of the FR . Would 'Lyn' actually be capable of traversing the whole FR, or would Garnedd Tunnel be the pinch point?

    Frank N.
     
  7. meeee

    meeee Member

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    Lyd doesn't have much superheat really. They aren't the same design as the other FR locos with an out and back loop on each element. They consist of a tube within another tube. So there is less surface area per element. They were also shortened over the winter because of cracking.

    Tim
     
  8. 30854

    30854 Part of the furniture

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    T'will be interesting to see how knowledge gained during the two (rather spledid) L&B recreations will translate into the design stage for the planned next pair.of MWs.

    (Part of me is still half wondering whether future L&B requirements might tempt 'em to build 'County Gate's' 009 2-6-6-2t Mallets for real .... note running number!
    54m.jpg.cf.jpg
    Image from www.009.cd2.com and well worth a butcher's!)
     
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  9. Jamessquared

    Jamessquared Nat Pres stalwart

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    Quite an entertaining model but I have a nagging doubt that that boiler wouldn’t keep pace with all those the cylinders! (And where is the ashpan supposed to sit? :eek:)

    Tom
     
  10. 30854

    30854 Part of the furniture

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    Gas fired compound perhaps? :Bag:
     
  11. 8126

    8126 Member

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    Oh, that is interesting, so coaxial superheaters like you find in some models (except those tend to be in stainless and extend into the firebox)? The other downside of those is no matter which way you arrange it, you end up having the hot return flow losing heat to the cool incoming steam. So Lyn is likely to have a really quite significant advantage in steam temperature, which probably explains the notably good water consumption previously commented on.
     
  12. andrewshimmin

    andrewshimmin Well-Known Member

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    Tom,
    Firstly, you're no fun any more...
    Secondly, presumably these guys have ash pans? https://upload.wikimedia.org/wikipe...emin_de_fer_du_Vivarais_à_Tournon_en_1978.jpg
    Thirdly, you don't need to worry about ash it you follow the prototype and simply fit a really big can motors where the boiler should be ...
     
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  13. meeee

    meeee Member

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    If it's working a heavy train on a decent run yes. I expect on 1 mile of L&B the loco will be quite wet because the superheaters don't have time to start working. You could have an endless debate on if the extra cost of superheating is really worth it on railways where you stop every 2 miles.

    Tim
     
  14. Paul.Uni

    Paul.Uni New Member

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    WHR event booking form and timetable teasers: https://www.festrail.co.uk/content/uploads/1/WHR-PPF_Booking_Form_v2_1.pdf

    Details and how to book for the solo Russell trips to Beddgelert: https://www.facebook.com/WHHRly/posts/2718600661515762 Relevant info in quote below for those who don't do FB
     
    Last edited: May 8, 2019
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  15. marshall5

    marshall5 Member

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  16. jon5051

    jon5051 New Member

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  17. jamesd

    jamesd New Member

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    Wow!! It doesn’t cover the whole WHR either - from the website:
    “Can be used during all three days for travel on all RhE • WHR trains between Porthmadog and Beddgelert, on event trains between Porthmadog and Boston Lodge and on all WHHR public trains.”
     
  18. 8126

    8126 Member

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    I think with superheat, if you want it to work on short runs, there's no point just tickling it. You need a lot to get the benefits quickly, since the superheater is going to get up to operating temperature in much the same time no matter how many flues worth you have, whereas the hotter the steam the faster the cylinders (which are the real thermal lag in the system) warm up. Lighter cylinders help here, I wouldn't be surprised if the Lyn's fabricated cylinders are also an advantage. Sentinels are obviously quite an extreme manifestation of this approach.

    The Ffestiniog, with its long steady uphill from one end of the line to the other, is probably one of the few preserved lines where low superheat still pays off, and the smaller your engine the faster it all comes up to temperature; a 2 foot gauge engine is a very different proposition to a standard gauge engine in this respect.
     
  19. Paul.Uni

    Paul.Uni New Member

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    Sorry about that. It seems they updated the pdf and the link I posted became broken as a result. The post has been updated with the current link.
     
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  20. Britfoamer

    Britfoamer Member

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    We've got a hotel booked for the event but went ouch when we saw the price of the rover tickets. I've just payed less than £100 for 2 x 3 day rover tickets for the G&WR event, very good value by comparison.
     

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