Flying Scotsman Speed

Whoah there!

I went to the NRM expecting to find that their graph of FS speed was one of the ones from the Railway Magazine of Jan 1935 that didn't clearly show a speed of 100 mph. I was wrong - their graph does show a sustained speed of 100 mph.

I studied the dyno roll from Mallard's run expecting to find evidence that they played fast and loose in their interpretation of the time and distance data. I was wrong - the dyno roll shows the same (odd) fluctuations in speed that the LNER reported. (I'm talking about their 125 mph claim in 1938 - not the later 126 mph claim) I didn't see the same speed as they stated - but there might be reasons for that.

None of this confirms that FS did 100 mph or that Mallard did 125 mph - but I do have greater respect for how they interpreted the dyno car data. The question remains whether those speed fluctations were possible - and I don't have an opinion on that yet.

Whether or not FS did 100 mph has no bearing on whether Truro achieved 100 mph ( as it happens I believe the evidence points to Truro hitting 100 mph - and that many GW locos had achieved 100 mph - light engine - before 1934 - as it appears to have been a fairly normal test when engines were built or repaired at Swindon).

What you can say in comparing FS and Truro is that 100 mph meant a lot more in 1904 than it did in 1934 - in 1904 the ton was faster than any car or plane - and slower only than experimental German electric railcars. (which were also faster than Mallard)

 

I think that light engines have been restricted in maximum allowable speed for a long time for good reasons so I do have doubts about one being driven in what would appear to be a reckless way.

 

I still insist that Papyrus was the first loco to achieve a sustained and provable speed of 100mph in the UK. So you can keep your FS's and CoT's, along with whatever fantastic thing GWR light engines are supposed to have done. But I'm glad City of Truro got preserved and FS got repaired because of their respective myths - it is only a pity Papyrus wasn't.

 

Did someone take a closer look at the single wheel that measured the velocity of the dynamometer car? It must have felt the influence of the railgaps and the like, the earlier remarks of peaks at identical locations of the road makes me suspicious.
kind regards
Jos Koopmans

 

There are similarities between FS and Papyrus (a distinct peak) - but Mallard is different (the speed rising, falling and then rising again) and in a different location. At some point in the future I will create an overlay comparing the three.

What I can say is that for Mallard there seems to be good correlation between the 24" per mile paper speed and the milepost locations marked by one of the pens on the roll (An engineer pressed a button when every mp was passed) - which you wouldn't get if there was a gross error in paper speed. (The paper was driven by the 9th wheel)

 

You've just been told that Scotsmans roll shows 100mph. What other evidence could you ask for to prove beyond reasonable doubt that 4472 achieved the ton? Video evidence?

There seems to me to be a desire to undermine Scotsman rather than look objectively at her record. If it was good enough for the LNER and Gresley (someone who insisted on 125mph for Mallard where everyone else insisted on 126mph) and we also have a roll showing the data of her run then logic dictates it's far more likely than not that she achieved it.

The LNER didn't play fast and loose with their data - everything I've read and everything far more knowledgable and respected persons than me say points to the LNER being very scientific in their approach and taking records seriously to the extent of questioning their own data and examining it carefully.

To be frank: on the balance of probability I think there's little to doubt Scotsman achieved it. Whether she achieved it as a 180lb A1 as easily as Papryus, a 220lb A3 Pacific, did, is another matter.

I agree with this though. It is a shame Papryus wasn't preserved.

 

just to be pedantic - the dyno roll for Scotsman hasn't survived - what I saw is the speed/distance graph drawn in pencil by hand (which an LNER draughtsman would have drawn from the dyno roll distance/time data)

 

Are you're sure you wouldn't like to qualify that unequivocal statement? [grin]

 

Cecil J Allen didnt think Flying Scotsman topped 100mph, despite being a LNER employee at the time.

There is something very odd about the original dynanometer readings as published at the time.

I was hoping to complete my re-hashing of City of Truro's run in 1904 but time has been very limited to do this the last few months. All I can say from what I remember of the primary source info from the original log in The Engineer was that Roux Marten's stated figures need a great deal of analysis, and much better than O.S. Nock attempted some 50 or so years later. I dont think Nock had the The Engineer log available at anytime, relying instead on the later Railway Magazine log a few weeks later that differs quite a lot. Then you have to compare this with the letters to the GWR by Rous Marten.

All very complicated!

Chers,
Julian

 

I seem to recall that GWR practice was to attach a couple of coaches to engines undergoing test runs after shopping, presumably so as to add brake capacity and also help steady the tender at speed. Certainly I have seen photos of "Kings" hauling two coaches which have been captioned as being on test. I'm sure @Jimc could confirm.

Tom

 

Or was it just photoshopped to convince Paulhitch that we can use kings on short heritage trains authentically?

 

I haven't spotted a reference to hauling coaches on the initial post works test run, but i have also seen references to locos being used for light duties in the Swindon area before going on to their allocated sheds.

 

Thanks - I'd seen pictures labelled as a "running in turn" but I guess that could encompass doing a local passenger duty prior to returning to the home shed.

Incidentally, I just re-read Tuplin's account of 2903 doing 120mph light engine on test. It's full of delightful detail about the run, which is convincing in every respect except that, by his own admission "no very precise details have been forthcoming" and the following three pages of yarn appears to have come almost entirely from his imagination! To which he closes "Had she beaten 100mph? No-one questions that even now! [...] Is there any evidence to suggest a 'Saint' might reach 120mph if driven 'all out' down a gradient of 1 in 300? Yes!" Though he has the good grace to suggest that "no one would seriously support the suggestion of 135mph" !!

Tom

 

Don't think you need almost in that sentence!

The 135 thing is the usual problem with granularity that bedevils all these measurements with devices/techniques of limited precision. In the case of that "135" figure it was from passing times recorded to the nearest 1/2 minute between signal boxes 4 and a half miles apart so the precision is not very high... Really the measurement would have been (at best) "anywhere between 108 and 180", ( or whatever according to how far the boxes really were apart and how recently the signalmen had reset their clocks), and if we assume that their 120 was a 7.5 second quarter then that probably means somewhere between 112 and 130 assuming they could clock to the nearest half second, although Collett's very qualified description of the episode suggests they had more than 1 fast quarter mile.

 

Tuplin isn't the source for 2903's run - that is Collett's statement to the Railway Magazine. For another high speed trial with a light engine see Cook's Swindon Steam. 108 mph with 5000 in 1927.

For another one this is from A H Vaughan (taken from GWR elist):

On 16 May 1928, No.6004 King George 111 built July 1927 was run
'light' from Swindon to Didcot - turned on the Didcot triangle and
returned. This was done twice that day. I had not looked at my
evidence when I wrote my ''By the Way' and the maximum speed was 102
mph on the DOWN journey, 2nd run.
Driver 'Clem' Crook and Fireman Humphries. Swindon men.

The purpose of this was to see how hot the leading axle boxes of the
bogie became under extreme speed.
I will put my evidence on this site. This takes the form of a postcard
photo given to me by Driver Crook's family showing the front of the
engine upon whose buffer beam two Swindon drawing office men sat at
102 mph taking readings from a thermometer. Each man sat on a wooden
box with a padded sack on top. Only one man is shown in the photo but
there are two boxes. The postcard image was not properly washed free
of chemical after 'fixing' and after 80+ years had become very
bleached. On the writing side of the postcard are the details of the
run.

Collett also stated (when asked if it was true that each King had been run up to 100 mph light engine when built) - "The Kings were designed for high speed and tested as such."

The practice of running engines light engine down inclines near Swindon dates back to the 1840s.

 

[QUOTE="Courier, post: 1581925, member: 10874]
Collett also stated (when asked if it was true that each King had been run up to 100 mph light engine when built) - "The Kings were designed for high speed and tested as such."

The practice of running engines light engine down inclines near Swindon dates back to the 1840s.[/QUOTE]
That is the sort of statement politicians are very good at. Answers the question without actually answering it.

 

For some time I have been studying Mallard's dyno roll - and I'm still some way off finishing. In the meantime I hope this is of interest - it shows the DHP (taken directly from the roll) and EDHP (my calculation) vs speed.

 

Enlightening. Looks like the Ceiling had just about been reached.

 

oh yes, that's 126.

 

This could either mean the cylinders were incapable of developing power over 120mph or that simply the cylinders were beating the boiler and that by the time they reached 120mph the boiler pressure was going down. I suspect the latter.