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Steam speed records including City of Truro and Mallard

Discussion in 'Steam Traction' started by Courier, Jan 30, 2011.

  1. Spamcan81

    Spamcan81 Nat Pres stalwart

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    Thanks. I’m sure I read in Bill Hoole’s biography of a similar feat.
     
  2. Miff

    Miff Part of the furniture Friend

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    But surely no evidence (anecdotes out of Popular Mechanics are not evidence) that 126mph was exceeded?
     
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  3. 30567

    30567 Part of the furniture Friend

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    I guess that's Winkworth's book with some esteemed timers. On a quick look through, most of the high speeds including the tons are eastbound while the fastest westbound is 94 by Mr Porter with most of the fast westbounds in the high 80s. That suggests a slight gradient bonus at work. Are there any examples of 100 at Farnborough eastbound? That would be more convincing given the level stretch from Fleet but I couldn't see any.
     
  4. Jamessquared

    Jamessquared Nat Pres stalwart

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    I guess the point about eastbound is that - regardless of gradients - you are running into congestion, not away from it. So you are far more likely to start hitting caution signals. Which doesn’t make fast times impossible, but I suspect makes them statistically less likely. That would then make a fear that is already rare going west even more rare going east.

    Tom
     
  5. MellishR

    MellishR Resident of Nat Pres Friend

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    This depends what you understand by "evidence". Certainly not conclusive primary evidence, but secondary evidence with some degree of plausibility, sufficient that the claim cannot be dismissed with certainty.
     
  6. Miff

    Miff Part of the furniture Friend

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    However it can be dismissed with derision, if the so-called ‘evidence’ is nothing more than “Charlie said”.
     
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  7. RAB3L

    RAB3L Member

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    Yes, but how many had 7ft drivers and an output of 7,200hp? The S1's test runs were certainly documented otherwise what would be the purpose of a test run? The T1's high speed runs on the Fort Worth to Crestline line were also documented and checked.

    That's clearly not the case, as my post explains.
     
  8. 30567

    30567 Part of the furniture Friend

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    Given that we are dealing in outliers there are all sorts of factors like the 3 coach night train on which 35003 did 106 happened to be an up train.

    I guess where I am is that there are two questions.

    Was an A4 or a MN capable of 100 with no gradient bonus? If Hailstone or Hoole had been told to go out with a special train and do 100 at Tollerton or Porter the same between Farnborough and Fleet, was 100 on level track possible? I think yes.

    Is there secure evidence that it was actually achieved? Depends on how quickly you think gradient effects run out and on what counts as evidence but I think no. And judging from @Maunsell907 contributions that seems to be where the RPS is.
     
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  9. Hermod

    Hermod Well-Known Member

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    Supply total length and mass of trains ,and I will do the hard slide rule work ?
     
  10. 30567

    30567 Part of the furniture Friend

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    Well why not take the dimensions of the Mallard record train or the Tregenna Castle run you've already been working with.
     
  11. Hermod

    Hermod Well-Known Member

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    I cant find them in this smokescren covered thread.
     
  12. 30567

    30567 Part of the furniture Friend

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    have a look at posts 97 and 111. Set gradient to zero and wind speed to zero.
     
  13. Hermod

    Hermod Well-Known Member

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    Mallard (100 mph =44.7mps)
    Length 154 m
    Mass 407 t
    Eqvivalent drag plate area 0.13*154=20.02 (m**2)
    Dynamic pressure 0.5*1.23*44.7**2=1228.82(N/m**2)
    Air power 20.02*1228.82*44.7=1099kW
    Roll power 407000*9.81*0.0015*44.7=268kW
    Needed cylinder power 1367kW==1830ihp
    V 2 was max 1990 IHP steady state.

    The UK fudge factor of 0.13 was found to suit Mallard at 124.5mph situation,with no correction for streamlining.The germans tested a streamlined 03 against standard and found a saving more or less like three squaremeter.
    I ougth to recalculate the Mallard situation with 2.5 sqm less flatt plate area and then adjust fudge factor
    The ugly thing with air resistance power (that dominates over say 50mph)is that it is a
    Cube function.Upping speed from 100 to 125 mph needs 59% more steam per time unit
    Reasoned objections apreciated
     
    Last edited: Feb 15, 2024
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  14. The Gricing Owl

    The Gricing Owl Member

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    I've avoided spending much time on this thread after my early posts in a former life, as I am right at my limit with owls and steam loco memoirs at present. So I'll try and stick mainly to facts as I am going outside (for owls and then Spa Valley), and may be gone for some time.

    Some runs I times behind Bulleid pacifics, all detail is for light pacifics except the first one.

    On the down road to Basingstoke, which is largely against the collar, on 15 May 1965 Gordon Hooper with fireman Dave Wilson on 35005 with ten cars reached 90 mph in the very short, slightly downhill 'Newnham Dip' which comes circa 13 miles after the long climb from near Byfleet to MP31.

    34087, on 12 cars for 430 tons gross at the end of June 1967, had a gentle start from Basingstoke, passing Winchfield at 82.5 mph. Where the loco was opened up to reach 91 mph around Fleet then a sustained 90 mph along the level stretch afterwards, before the Eastleigh driver had to slow for a 60 mph tsr at near Sturt Lane Junction. Then, and not totally relevant to a Bulleid reaching 100 mph on the level, an astonishing departure from Woking on that load to reach 84 at Hersham. I rate this as amongst my very best Bulleid runs, MN or Light Pacific.

    Gordon Porter, with a very badly steaming 34101 (needed a wash out and with not very good coal) on the up mail on the slow line with 10 cars for 325 tons gross on 19 February 1966, went through Winchfield at 88 mph and, yes using the slight grade , got to 90 mph at/after Fleet, before easing for the often quoted but without limit boards, 65 mph at Farnborough on the up slow line. We went through at 83 mph. Boiler pressure was 200 psi at Basingstoke, 145 psi at Winchfield and 140 psi at Fleet - Tommy Molt on the shovel was having a really rough night trying to keep the pressure up - a common place occurence towards the end of SR steam with poor quality coal and with regular maintenance was not being carried out when it should have been. I was on the footplate from Basingstoke to Surbiton that night, and could see the work Tommy was putting in at the Basingstoke, Woking and Weybridge stops to keep some sort of half decent boiler pressure.

    Then there is the wonderful run with 34102 Lapford in April 1967 with the so recently and so sadly lost Clive Groome driving. Just 6 cars for 210 tons, and from the Basingstoke start eased up to 92 mph at Fleet with none of the utter thrash and fire throwing when Gaffney took the same loco up to 100 mph a few weeks later. Then 95 mph at milepost 35, 98 mph at Milepost 34 - then a change in loco control settings saw a drop to 95 mph at Farnborough, before reaching 98 mph (possible 98.5 mph - I haven't fully analysed my log yet) around milepost 32. It's all level track from circa milepost 35.5 to circa milepost 32. R.I.P Clive.

    I have a number of MN runs on ten or eleven cars that reached what were probably speedo tons for the driver, but actually fell in the range 97 - 98 mph after Winchfield. I don't think any of those were reached on the level stretch, partly because of that annoying tsr near Sturt Lane Junction near the end of steam, and partly because the drivers thought they had already got their tons.

    There is enough there, ignoring the lightweight load runs of 35003 (including my 106 mph on the footplate on 26 June 1967), to suggest that a MN on ten or eleven cars could have accelerated to 100 mph or more on the level stretch from mp 35.5 to mp 32.

    As for a Bulleid Light pacifc? Certainly yes, but I'm not sure how much more of a load than the 6 /210 tons that Clive Groome had with 34102, that could be achieved with.
     
    Last edited: Feb 15, 2024
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  15. Spamcan81

    Spamcan81 Nat Pres stalwart

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    What a shame you weren’t timing the alleged 150 run with that Pennsy duplex mentioned earlier. :)
     
  16. Hermod

    Hermod Well-Known Member

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    Are there other members than mr Martin having acces to the Mallard NRM roll?
    In that case everything written here has not been in wain.
    We know that one revolution of paper-drum is equal to one mile railtravel within 1 part in 2000.
    We know that one revolution of roll activates four more or less equidistant markings called quarter miles.
    A clockwork marks either half or whole seconds
    Is it possible to asign whole second numbers and first decimal to each quatermile mark?
    To within 0.1 or 0.2 seconds and without to much bias?
    We will then be able to calculate whole mile average velocities to within the accuracy of drum to rail and clock to time ratios.
    If we do it from every quatermile(start time 0 at MP89.75?) to say MP 94.5 we have extracted what is possible from roll markings.
    Plot them and ask a shipwrigth or artist to make best fitting curve and the question of Mallards top speed is still confusing but at a higher level ,
    No high quality scan or photography needed.
    Only counting from 1 to ca 170 and assigning 0.1 second values to each quarter mile mark.
     
    Last edited: Feb 15, 2024
  17. 30567

    30567 Part of the furniture Friend

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    Thanks Bryan. So 2 mins dead Fleet to Farnboro/vv would be very convincing evidence in my book. Looks like the Groome run will have been close to that.
     
  18. Hermod

    Hermod Well-Known Member

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    Dear Bryan Benn

    Can You inform us who calculated the speed numbers and from what source?

    Kind regards

    Hermod

     
  19. The Gricing Owl

    The Gricing Owl Member

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    I've glanced at this thread from time to time, but strictly avoided making posts for the reasons in the first line of #974.

    I broke my rule on posting here as the subject of Bulleid pacifics running at or close to 100 mph, as you may have guessed from that post, is something I was very close to in the 1960s before the world came to an end on 10 July 1967! And I hoped a mainly factual post here would help the debate amongst those I very much consider as online friends, and, on a secondary basis, help me as I work on my BR SR steam locomotive memoirs. Without me needing to come back with any frequency for the follow up on that specific subject.

    Re your questions, I am sorry, but it would be wrong to give a half answer 'off the top' for such an important subject. And to give a proper answer I would have to first find, and then dig into my computer and document archives for something I did circa 18 years ago.

    Doing that is way out of my reach at present.

    Bryan B
     
  20. Hermod

    Hermod Well-Known Member

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    Thank You for answering.
     
    Last edited: Feb 16, 2024

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