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6023

Discussion in 'Steam Traction' started by Eightpot, Oct 4, 2011.

  1. Phil-d259

    Phil-d259 Member

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    It should be noted that as far as NR are conferenced, a tender is considered an integral part of the locomotive it is attached to. Should the two be split at any stage, then rejoined (as has happened a couple if times at Swanage in the past) it is necessary to undertake another 'fitness to run' inspection / exam by an approved inspector before the loco is allowed back on the national network.

    As such it really makes no difference whether the air pump is on the tender or the loco.
     
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  2. green five

    green five Part of the furniture

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    6023 now appears on the SVR website roster page and will hopefully be operating test trains from 27th February to 1st March between Bridgnorth and Highley. The King will be top n tailing with a Class 50.
     
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  3. aron33

    aron33 Member

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    Interesting...
     
  4. windytinker

    windytinker New Member

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    I believe I am right in saying that Air Pumps are now required to be on the Locomotive itself rather than the tender. With Clan Line being the first of current main line scene Loco's to be fitted with Air Braking it's setup pre dates the group standard.

    The MNLPS changes the steam supply pipe to the compressor at regular intervals to make sure all stays well, but it is no longer seen as the ideal solution.
     
  5. Aberdare

    Aberdare New Member

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    6024's new cylinders, how it was done.

    The need to reduce the overall width of the locomotive was well understood to avoid gauging restrictions, a number of options were explored.

    1. Move the centre line of each cylinder closer to the frames on each side. Initially this was considered as a logical step but quickly dismissed because of multiple complications such as altering the valve gear, realignment of the slide bars and connecting rod etc. The greatest difficulty came from the positioning of the trailing bogie wheels which occupied the space between the frames and the cylinder casting, moving the cylinder inboard would have resulted in the tyres hitting the cylinder when the locomotive rounded a sharp curve.
    2. Reduce the cylinder diameter. The original design produced a cylinder 16" in diameter with a bell mouth of 16 1/2" diameter, the bell mouth being where the cylinder cover locates into the bore and it defines the maximum diameter that a worn cylinder can be increased to before a liner is fitted. The expected work of the locomotive indicated that its life would be limited by factors other than cylinder wear so the front bell mouth was reduced to 16" and the bore reduced 15 3/4". The back bell mouth was reduced to 15 3/4" to that the cylinder at this end was stronger to withstand the stresses generated by supporting the slide bars. The reduction in bore would reduce the nominal maximum effort but this is countered by the reduction in maximum wheel diameter to reduce the locomotives height. The inside cylinders were fitted with liners to bring them down to the same diameter.
    3. Reduce the cylinder wall thickness where the cylinder covers attach, this being the flange that is the widest part. The flanges at each end of the cylinder are massively strong but locally weakened by the holes for the 13 cover studs of 7/8" diameter each. Not only does each stud weaken the cylinder but it also introduces considerable localised stress. Replacement of the 13 studs of 7/8" diameter by 28 studs of 5/8" diameter not only allowed a reduction in wall thickness but it also allowed for a further reduction due to reduced localised stress. The original design has one stud on the horizontal centre line, the new design had two studs equidistant above and below the centre line and this permitted an additional small flat surface to make the flange narrower. In addition originally one of the cladding mounting screw holes coincided with the stud on the horizontal centre line, the consequential stresses around this hole could be discounted if the hole was moved to a location where the material could be thicker. Each of these changes allowed for a small reduction in width but overall they became significant.
    4. Material. The original cylinders were cast from 14 Ton grey cast iron but the new cylinders are from 17 Ton grey cast iron, because of this wall thickness could be further reduced. SG iron was considered but as SG iron has poor wearing qualities a grey cast iron liner would be needed and this cancelled out any benefit of reduced cylinder thickness by the use of SG iron for the cylinder.
    These changes reduced the width of the casting by 1 5/16" each side, in addition the cladding is recessed and bolts removed from critical locations to give a further saving of 1/4" each side. The overall width of the locomotive at cylinders is reduced by over 3".

    The design and drawings were produced for 6024 Pres Soc and a Stress Engineer appointed to confirm to the satisfaction of the VAB the design was stronger than the original.

    Andy.
     
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  6. Penricecastle

    Penricecastle Member

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    That's great news! I guess they'll unleash 6023 on Eardington bank.
     
  7. Kylchap

    Kylchap New Member

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    Thanks for providing such a detailed and interesting explanation. I wonder if there is any prospect of 6023 following suit.
     
  8. toplight

    toplight Member

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    I did see articles about this guy falling between the platform and the train and wondered whether in response to this kind of accident NR are moving the track closer to the platforms to reduce the gap, hence the problems with gauging and need to reduce widths of locos like 6024. What do people think are NR doing this ? In the case of this accident the platform was on a curve so the gap would be bigger.

    https://www.standard.co.uk/news/uk/...-platform-sues-rail-firm-for-2m-a3761221.html
     
  9. flying scotsman123

    flying scotsman123 Part of the furniture

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    I thought it was well documented that that was exactly what was happening.
     
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  10. LISTER B

    LISTER B New Member

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    ;)
     
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  11. GWR4707

    GWR4707 Resident of Nat Pres

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    Its been discussed on here many a time....

    Not according to the latest GWS Echo, no, although things change I suppose overtime and will depend what aspirations are when the new boiler ticket kicks in (assuming they turn her round after this one expires), for those who know about such things, how much would casting and machining a set cost assuming that the 6024 group make the patterns available?
     
  12. toplight

    toplight Member

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    I can't see it happening for 6023. The guy I know who works on it told me there was only 4 people who worked on 6023 with others borrowed occasionally and I can imagine it is a huge amount of work to do. People assume there is available free knowledgeable labour out there to do all these tasks when often there isn't or it is in very short supply.
     
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  13. flying scotsman123

    flying scotsman123 Part of the furniture

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    And this is, I'm afraid, my criticism of Didcot. I think it's a similar number working on Pendennis Castle? And probably similar for other projects. I fully appreciate it's hard to reallocate volunteers away from their "own" projects if that's what they want to focus on, but if there was a little bit more focus then it might provide a better sense of achievement and more volunteers joining as locos returning to steam would be a more regular occurrence.
     
  14. LesterBrown

    LesterBrown Active Member

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    Just how many mainlin.e locos do Didcot aspire to. If only one or two it probably makes more sense concentrating on 4079 even if it does mean a second, new, cab and borrowing 5051's chimney.
     
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