City of Truro's speed record

[OnTheBranchline]

Normally a record is usually a record without dispute.

[Karhedron]

Because of the way the speed was recorded. It was a chap with a stopwatch recording the time between mileposts which is not a particularly robust measure. This does not mean CoT did not hit the magic 100, just that the evidence is not as solid.

 

Later speed records were recorded with dynamometer cars and the results examined which makes them much more reliable and less open to question.

[DavidH]

There have been a few articles written in the railway press about it, which are worth seeking out if you're interested in the subject. One objection if I recall is that it is doubted that 3717/3440 could have generated enough power to reach that speed. I think there was an article in Steam Railway last year about the various "top speeds", although I can't access my back issues to check for you at the moment.

 

Equally, there are questions about Mallard's speed as well. The 125.5mph claimed (not 126mph although that may have been reached for a brief moment) was just enough to beat the German loco's top speed of 124.5mph. (The German loco, 05002, didn't break down immediately afterwards, unlike Mallard, and has recorded nine high-speed runs, and did it on more or less level track, so has a good claim to be the fastest loco, even though it doesn't have the fastest speed - if you follow my drift.)

 

And questions about Scotsman's 100mph too ... was it just 98mph, was that 100mph a glitch in the speed trace?!

 

The Steam Railway article (at least I think it was Steam Railway) resulted in one grumpy letter about it being fashionable to belittle Britain's achievements and why couldn't they leave speed records alone! I think the writer missed the point that it is the job of historians to review evidence, and report what they find - why should speed records be different to any other area of history open for interpretation and evaluation? Indeed, isn't it more vital that such claims are able to withstand scrutiny? (That's just my opinion, mind you.)

[Guest dilbert]

It's like one of Geoff Hurst's goals in the 1996 WC - was it or wasn't it a goal ? The technology at the time couldn't give an answer but does It really matter (unless you are attempting to rewrite history)?.... aren't the steam records are held by the City of Mallard ???... dilbert

 

edit for a couple of tpyos in bold

[gwrrob]

It's like one of Geoff Hurst's goal in the 1996 WC - was it or wasn't a goal ? The technology at the time couldn't give an answer but does It really matter (unless you are attempting to rewrite history)?.... aren't the steam records are held by the City of Mallard ???... dilbert

 

I don't remember winning the world cup in 1996.Must have dreamt that.

[Guest Phil]

There have been a few articles written in the railway press about it, which are worth seeking out if you're interested in the subject. One objection if I recall is that it is doubted that 3717/3440 could have generated enough power to reach that speed. I think there was an article in Steam Railway last year about the various "top speeds", although I can't access my back issues to check for you at the moment.

 

I think I've read that the techies claim the "engine" part of CoT couldn't physically produce the hp output required to propel the train to the speeds quoted. There is apparently a limit to which reciprocating machines linked with the valve events through which the steam has to pass through, can function.

[Mike J]

For it to be an authenticated record, there must be proof of the speed indicated by a generally accepted measuring device. Obviously, this is only as accurate as the technology of the time. As Karhedron says, the City of Truro "ton" was recorded using a stopwatch and milepost sightings, which is open to massive inaccuracies when high speed is involved.

Also, City of Truros 102.3 mph, Flying Scotsmans 100mph and Mallards 125.5/125.88/126/126.2 mph (take your pick) were all absolute maximums. Gresley only ever claimed 125 mph for Mallard as he felt a sustained effort over 1/4 mile was a more accurate assessment.

The two later efforts listed above were generally thought to be irrefutable at the time as they were measured using the dynamometer car, which is positively archaic by todays standards.

Many who dispute the City of Truro claim cite the reason that the locomotive was too small and not capable of producing the power to achieve such a speed. But, after a review of the evidence by one eminent railway historian/analyst (sorry, I can't recall who) in Steam Railway magazine the decision reached was that because previous calculations had under estimated the power output and free running qualities of this locomotive, coupled with the fact that Wellington Bank would give considerable gravitational assistance, it may just have been possible and a speed around 100 mph was probable. Still, there is a big difference between possible, probable and irrefutable.

Even sat nav readings used today are open to question, as happened on the recent German steam run when speeds between 98 and 101 mph were recorded, depending on which side of the train, where you were situated about the length of the train, and which sat nav device was used seemed to make a difference.

[beast66606]

Because of the way the speed was recorded. It was a chap with a stopwatch recording the time between mileposts which is not a particularly robust measure. This does not mean CoT did not hit the magic 100, just that the evidence is not as solid.

 

Exactly - it was claimed it covered 1/4 mile in 8.8 seconds, which equates to 102.3 mph.

 

A +0.3s variation drops the speed to below 98.9mph, conversely a -0.3s variations boosts it to 105.9

 

A 0.6s variation in the time gives a 7mph - or roughly each 0.1s inaccuracy gives a 1mph change to the speed.

 

It's hard to measure accurate (certainly to within 0.3s) using a modern digital stopwatch never mind an old mechanical, analogue one*, especially when travelling at high speed and passing a given point - hence the doubt.

 

* which apparently only measured in 0.2s increments.

 

(If I've done my maths correctly)

[Guest dilbert]

I don't remember winning the world cup in 1996.Must have dreamt that.

 

A fair cop... just edited my original for the obvious errors ...dilbert

 

PS it would appear that edited posts don't always show as such - must be a software bug somewhere

[34theletterbetweenB&D]

The time was recorded over quarter miles. Was this done visually by sight of the QM posts or by counting the 60' rail joints? There's error potential in those too, in addition to the inaccuracies inherent in the stopwatch operation. The recorder has to observe the distance marks, operate the stopwatch(es?), write down the data accurately, all in a rocking and rolling train at sub ten second intervals. Notice that at no time did the original recorder of the data make the 100mph claim: he knew the limitations of the method too well to suppose that this claim was strong enough to stand. Plot the original data on a graph and apply a curve fitting programme. Mean line peaks at about 96mph.

 

It really cannot be seriously considered as a 100mph. A good instrumental technique with some sort of trace taken in real time is what is needed. Ironically it was the NER copy of the GWR dynamometer car that was instrumental in proving where this speed was attained on rails in the UK.

[Guest Belgian]

Whatever speed it was, it was sufficient to have resulted in the engine's preservation for us all to admire today!

 

JE

[Peter Kazmierczak]

 

 

Equally, there are questions about Mallard's speed as well. The 125.5mph claimed (not 126mph although that may have been reached for a brief moment) was just enough to beat the German loco's top speed of 124.5mph. (The German loco, 05002, didn't break down immediately afterwards, unlike Mallard, and has recorded nine high-speed runs, and did it on more or less level track, so has a good claim to be the fastest loco, even though it doesn't have the fastest speed - if you follow my drift.)

 

 

If there's doubt about Mallards record, surely then there could be a doubt about the German one too?

 

I don't think it's fair to say that Mallard broke down immediately afterwards. It reached P'boro OK, though granted it was taken off the train there as it was, shall we say, a little tired after its exertions.

[beast66606]

PS it would appear that edited posts don't always show as such - must be a software bug somewhere

 

Not a bug, a change, you can choose to have the post marked as "edited by ..." or you can choose not to

 

Sorry, wandering off topic.

[John_Hughes]

It's only fair to point out that the justified honours given to the City of Truro should't eclipse the sterling efforts of others.

 

When she'd been taken off the train at Bristol (die to concern about lack of coal in the tender) the trip to London was completed by Dean's 4-2-2- Duke of Connaught, which - given a clear road - managed the 119 miles from Pyle Hill Junction in 99 minutes - in itself an incredible achievement for a loco which was well past the first flush of youth.

[melmerby]

There is ample evidence to show the "City" class locos were certainly capable of speeds into the nineties, so a top of 100mph for "Truro" is a possibility, even if it has not been authenticated with 'accurate' timekeeping.

 

Keith

 

EDIT:

There problem with rail speed records are that there are hardly any comparable runs e.g. different locos on same line. So what might a Coronation have done with a trip down Stoke bank?

 

There are also locos that where specifically built for high speed such as the Milwaukee F7 which were claimed to be able to run at 120mph on level track and certainly had the power and wheel size to do it, but were never 'accurately' timed.

 

Keith

[Oldddudders]

Debunking heroes has become a fashionable activity, and this is no different - however learned the investigator and rational his analysis.

 

As far as I am concerned CoT - and Mallard - did what they did.

[DavidH]

Debunking heroes has become a fashionable activity, and this is no different - however learned the investigator and rational his analysis.

 

As far as I am concerned CoT - and Mallard - did what they did.

 

I find it regrettable that historical investigation should be seen as entirely negative "debunking". It is subjecting presumed fact (and past interpretation of evidence and opinions thereof) to careful review to see whether any new insights can be gained.

 

I like to know that the things I hold dear as "fact" can stand up to scrutiny.

 

What you seem to be saying, it seems, is that no one should ever question anything or that if enough people want or believe it to be true, then it's fact. That's a slippery slope ...

[DavidH]

If there's doubt about Mallards record, surely then there could be a doubt about the German one too?

 

I don't think it's fair to say that Mallard broke down immediately afterwards. It reached P'boro OK, though granted it was taken off the train there as it was, shall we say, a little tired after its exertions.

 

There could be doubt about the German one, although reportedly 9 runs of 110mph and higher, with two runs over 120mph, one up to 124.5mph, without significant gradient assistance, can only merely suggest that if the two locos were given a level playing field (so to speak), the German one would be faster.

 

But, Mallard is still the fastest, unless it can ever be proven otherwise, and on current evidence I doubt it will.

 

I am using "immediately" correctly! :-) However, to avoid needless semantic argument, what if I say "failed shortly after"? ;-)

[Guest dilbert]

Not a bug, a change, you can choose to have the post marked as "edited by ..." or you can choose not to - of course this opens a can of worms because troublesome posts can be silently edited after the event to make the poster appear sweet and innocent but no-one would ever do that ... would they.

 

It doesn't bother myself that a post is edited that this is indicated (by the original poster or someone else)... the same probably applies for most people. As for 'troublesome posts' there are other ways of managing these...

 

Back on topic,..

 

History is history, you can take all the rugby match results when a try was worth four pts and these results to reflect a try worth five points - there are several outcomes that would change - is this significant? Does it really matter several decades on that one or t'other loco, if using latest technolgies, did or didn't make a certain record ? ... dilbert

[beast66606]

 

It doesn't bother myself that a post is edited that this is indicated (by the original poster or someone else)... the same probably applies for most people. As for 'troublesome posts' there are other ways of managing these...

 

Troublesome posts ? not sure what you mean there, I didn't say that.

 

see how history can be changed

[DavidH]

History is history, you can take all the rugby match results when a try was worth four pts and these results to reflect a try worth five points - there are several outcomes that would change - is this significant? Does it really matter several decades on that one or t'other loco, if using latest technolgies, did or didn't make a certain record ? ... dilbert

 

That's not at all a like-for-like example ;-)

 

I'm not trying to do anyone down, or say that their beliefs and passions are wrong - I just believe that we should always keep an open mind and remain receptive to new ideas and interpretations of history. History is not just history. The way it has been recorded, interpreted, structured, conceptualised, etc etc, changes through time. From time to time new approaches throw new light on past events that open up new lines of enquiry and ... well, you get the picture I'm sure :-)

 

I've just copy-edited a fascinating book on Historical Thought. Every chapter deals with difference aspects: Foucault, the Annales School, Marxist thought, Subaltern studies, women's studies, Hayden White, history from below, even interpretation of photographs and the way the internet is affecting history, and lots more. You think a speed record is contentious ...

[Guest dilbert]

 

 

 

Troublesome posts ? not sure what you mean there, I didn't say that.

 

see how history can be changed

 

I shall take this offline with Andy - this post is a disgrace... dilbert

[Andy Y]

I shall take this offline with Andy - this post is a disgrace... dilbert

 

Don't get silly and uppity please; beast did that to illustrate how some people can re-write their version of history. Of course he said it.

[beast66606]

Don't get silly and uppity please; beast did that to illustrate how some people can re-write their version of history. Of course he said it.

 

And of course it was Dilbert who prompted the whole thing in the first place by asking "PS it would appear that edited posts don't always show as such - must be a software bug somewhere " maybe he's got my invisible ink and spilt some on his own postings.

[PhilH]

I think this thread amply demonstrates the glass half empty approach so prevalent in this country. As has been pointed out above any error need not have necessarily been on the minus side - the thing could actually have been doing 105mph...