Steam speed records including City of Truro and Mallard

Being charitable, my assumption is that humour doesn't always come across easily in a second language, so it's a good idea to use smiley faces to show you're joking. Otherwise it can read like unnecessarily snarky language, in response to a polite, uncontroversial message.

Simon

 

I'd assumed that as forward visibility had taken a big hit, it could only travel tender first anyway…

 

Forward visibility is over rated. A hundred years ago, Lindbergh flew across the Atlantic in a plane with no front window. And he had three dimensions of movement to think about, not just one. Solo …



Tom

 

You're the one seeking to disprove Mallard's speed record, so it is implicit upon you to provide this information and say whether it is possible or not. Simon has, I think, been very reasonable with you (more than I would have been) so I would advise you to stop antagonising him.

So carry on: do the calculations yourself. We expect your working to be shown for others to examine.

 

Non-railwaymen tend to equate driving a train to driving a car where visibility is essential to guard against suicidal pedestrians, cars emerging unexpectedly from side streets, traffic lights turning red as you approach them, etc. On a train, you mostly drive on the signals: if you have a green signal ahead then you're clear throughout that section. If you're on the main line at speed and something appears ahead, there is little you can do anyway. For the most part, you cannot stop within your seeing distance, and you certainly could not back then. And as for swerving around it . . .

 

If you intend to continue like this perhaps you should consider 'adjusting' your forum signature

 

Still here Victor?

No change necessary from my part.

I have said what I needed to say, I am content to disappear into the ether again.

Sad that you are still singling me out despite this being raised to you before.

Not necessary as you will see that the dynamometer roll will give you all of the information required to work out the drawbar horse power, including its own recordings, and from there you can make the necessary calculations yourself.

Good luck!

 

Apropos of no one in particular, this thread has often reminded me of the old saying that the reason why academic disagreements are frequently brutal and vitriolic, is that there is so little at stake.

 

That much increase in speed could not have happened in a few seconds. The measurement system was evidently subject to random and/or systematic errors (as are all measurement systems). Those who care about the instananeous maximum speed need to apply informed guesswork as to what the trace would have looked like without those errors. I agree with Simon that the sustained power output up the bank and down the other side, and the sustained speed of around 125 mph over a significant distance, are more significant than the instananeous maximum, whatever that may have been.
Edit: corrected typo

 

There is actually quite a lot at stake.
British engineering / evaluation being doubted as worlds best 1938 is not little.

 

OK
Letter 610 shows three different evaluations of roll from mallards last fast miles.
The black is based on (one mile/one revolution of paper drum) mean values.
The red is based on five seconds paper feed as used by LNER 1938
and the blue uses even shorter intervals and the only one enabling 126 mph Claim.
Over 200mspeed rises from (124.5mph/55.65msec) to 126/56.32 according to blue curve from a NRM analysis .
Kinetic energy is .5*mas*velocity squared
619MJ to 634MJ that is 15MJ suplied over 3.6 second or ca 5700 horsepower extra to the ca 2000 from Mallard for air,rolling and helped by gradient.
Red Gresley curve is not quite so crazy but still.

 

As @Jamessquared has pointed out, unlike most 'speed records' there isnt for obvious reasons a 'standard' to set a record against.

Secondly whatever you think of the merits or otherwise of the two loco's - and the issues that surround them, A4's 35 were built and they were in front line service for 30 years, this compares with 3 DR class 05's. While its not an entirley accurate methaphor its a bit like comparing @Victor Jag with a Formula 1 Car, yes it may be faster but it cant do the ASDA run.

So I suggest that Mallards claim to be 'The Fastest' stands on those grounds alone

 

Not The Worlds Fastest ,but UK OK.

 

Sigh. I can’t in all good conscience ignore what’s being said, so to clarify:

We actually covered the 05 002 speed run some months ago.

I have a good copy of the only evidence we have of its run - a tracing of the speed versus the distance. We don’t have any time stamps.

The trace only claims 124.5mph. That’s 200KPH. Nobody in Germany claims more than 124.5mph. This locomotive did a sustained 120-124mph for several miles throughout the trip.

Mallards actual dynamometer car record shows 125mph, sustained, and over 120mph running for over a mile.

We have done this dance before. Mallard was faster, on a minor falling grade. 05 002 was accelerating uphill when it achieved 124.5mph. There are some questions to answer on that score.

If you go back in this thread and the Gresley thread you will see a pretty comprehensive break down of the issues but the fundamental fact is Mallard was slightly faster, both locomotives’ runs were impressive.

In 1938 the ETR 200 was running in Italy as a streamlined electric high speed train and did 126mph in 1939.

So to be honest, arguing over whether Mallard or 05 002 was faster in terms of high speed rail, is pretty irrelevant. They were already by technology terms obsolete.

But even a basic cursory understanding of numbers means that 125mph is higher than 124.5mph.

There endeth the discussion!

 

You may think that.........................

Next question -- did FS actually do 100? See Bryan Benn of this parish and the mysterious case of the dynamometer car uptick.

 

I think the only British locos that managed 100mph without destroying:

• The space-time continuum
• The buffet car crockery and large sections of pointwork at the following station throat
• Their own middle big end

... were the Bulleid pacifics. So they are the only verified and reliably fast British locos



Tom (runs for cover)

 

It is a shame you cannot read german.
It is explained that the 200,4kmh over 5 km was measured the Mallard way by a rotating one km roll.
Even if roll was wanky like Mallards does not matter as it rotated exactly five times.
What You call only trace is most likely the picture from an official report loaned by mr Wolf(05002 designer) to author Gottwalt after WW2.
Stating that 125 is higher than 124.5 is superfluous.

 

Usually on lines sighted for 75mph. One R Deeth shared the laundry challenging consequences of hitting the ton heading towards Winchester, and then realising that he had misread a signal and the home was “on”!