4468 Vs 05 002

Apologies if this is hard to read but thought it would be interesting to overlay the speed curves of Mallard (blue - of course) and 05 002 (black). Interesting to see how 4468 had to put a lot of effort in working up speed from Grantham. Also people assume 4468 limped into Peterborough with a hot bearing - whereas actually it ran at about 70 until Werrington.

 

Interesting indeed, actually illuminating. I have been aware that just how very considerable the sustained power output of Mallard
was right through from Grantham - first to get the speed over the top of Stoke and then to accelerate beyond - but I had not had in my mind
the degree to which the speed rose up hill, nor realised that the gradient profile in Germany was not dead flat.
Both the the general gradient diagrams - an ascent, then the speed record - and the speed graphs immediately afterwards
are eerily similar.
Could I ask two questions? Both about the German record. What does the graph line at the bottom labelled "Zn" represent?
And am I right to think it was before this trip when the Deutches Reichsbahn had a failing big end problem after this sort of speed?

 

I assume that the scale at the bottom is km and that one or other colour has been stretched or squashed to make both the horizontal and vertical scales equivalent. Until now I had understood that the German loco maintained a speed close to 200 kph for a long distance. These curves do indeed look very similar, but they're not very clear. Is it possible to post a clearer version?

 

- Drawbar pull in tonnes
- I don't know

 

hope this helps

 

It does indeed -- giving us a mass of information to try to digest. Is the reason for shutting the regulator from time to time known?

 

I have read in german(isbn 3882552166 )that feed water pump was not big enough and water was falling.
Mallard was starting to break crank and 05 to blow boiler
At 200 km/h.
Steam locomotives should have been ordered by law to stay under 120km per hour like in France.

 

Sorry to criticise the graphs, but 200kph is 124.274mph so Mallard's sustained 125mph should be a bit higher on the graph.

 

I may have been too terse in my previous comment.

There was a speed limit through Grantham and to go really fast down Stoke depended on seriously accelerating up the 1 in 200 to the summit
You had to have everything right before Grantham and then really go for it - hence some of the remarkable speeds with Bill Hoole, he normally
kept his locomotive as extended as far as it reasonably could so he had the speed out of the tunnel and past Stoke box, after that it was
simply a matter of not easing off. Hence the continuous power output being so high both before and during the particular bit at 100 mph
and more.

The Germans had had trouble with big ends after these sort of speeds. Having attributed this to there being no cushioning effect from residual
steam in the cylinder so that all the inertia of the piston, piston rod, crosshead and connecting rod was visited on the big end bearing, they
issued instructions that until some lesser speed was reached steam was to be kept on. This was successful but never widely realised here.

It is not clear whether the inside big end went on Mallard after its record because of the valve to the inside cylinder overrunning or because
steam was shut off at over 120 mph and there was no cushioning effect. The train was formally - and practically on the up trip before they came back
from Barkston - brake trials. For comparable stopping distances they must have been conducted with the regulator shut.

(At least they stopped in Peterborough and took Mallard off. There was an attempt for some comparable speed but the driver was not told in time and
did not have the speed at the top of Stoke nor the speed they were hoping for down it. Presumably they kept trying too late and then had to break hard
for the low speed restriction at Peterborough no doubt with the regulator shut. The denouement was that the inside big end failed and the driver was told,
by Thompson who was on the footplate, to keep going through to Kings Cross. The driver obeyed and it does not seem that the engine was necessarily eased.
By the time they were coming in from Potters Bar it was obviously dire. The A4 - Flying Fox? - made it through but the big end was well on the way
to breaking up on arrival. It seems they may have just made it: if the piston, not controlled as it needs to be via the connecting rod had overrun
you could probably have written the inside cylinder block off, never mind anything else.)

 

The loco was 2512 Silver Fox (So you got the right animal. Flying Fox was an A3, 4475/60106) in 1936. That run was on the up Silver Jubilee, I believe the only time the LNER actually attempted a speed record on a public passenger service (When Silver Link reached 112 on her demonstration run, the crew believed they were doing about 90, so smooth was the ride!). It is worth noting that they did get the then-record, by 1mph (113mph, beating Silver Link's 112), so it is one of those interesting 'what-ifs' - had the driver been given the notice upon departure from Newcastle, how far greater a speed would they have reached? Would it have been so great that the LMS was unable to match it on Coronation's test run, thus negating the need for the LNER to claim back the record with Mallard, and would we have a lower British speed record held by Silver Fox, which probably would have been preserved as a result at Mallard's expense, and the undisputed world speed record belonging to the Germans? Would it have caused the LMS to push 6220 so hard that it actually resulted in a derailment and loss of life? Would the LNER have attempted the 'brake test' on July 3 1938 with Mallard anyway as yet another attempt to put themselves further in front with the British record?

 

That should be enough froth to keep us going at least until the new year!

 

Thank you very much for the details.

I had been wondering if that extraordinary press run behind Silver Link - then very new and as it was unique it had to run the service single handed for the next three weeks -
meant that an A4 would cruise happily at 112 mph but possibly not.

And you have jogged me into putting two and two together: it was just the same with the BR 2-10-0s the drivers went as fast as it felt, which was decidedly more than what
they first thought. John Powell in "Living with LMS Steam" has a marvellous story about managing to persuade Newton Heath loco crew to take them on excursions to
Llandudno after they jumped to the conclusion they must be like Austerities - same designer and all - and the reaction the next day. People could quickly get used to
their turn of speed.

 

Not quite.
Fox: Dog
Flying Fox: Bat

 

As somebody with a Zoology degree I should have known that! However, I generally know and refer to flying foxes as fruit bats. So if we are to take Flying and Silver as merely adjectives describing the animal, not flying fox being a specific animal (which was the conclusion my brain jumped to), I could still technically be correct...

 

But they weren't though, were they. What France did was entirely up to them.

Dave

 

Fox, Bat or... Horse?

https://en.wikipedia.org/wiki/Flying_Fox_(horse)

 

It's the horse. 100 per cent it was named for the horse.

 

The question is, what was the horse named after? A fruit bat, or an actual fox that was able to fly...?

 

Mallard? Crank? Try middle big end bearing getting hot. Wouldn't have happened if the regulator had not been fully closed so robbing the cylinder of cushioning steam. Same thing happened in Germany when they were engaged in high speed running. Chapelon Pacifics had little trouble running at approx 176km/h when testing electric locomotive pantographs, though this was tame compared with what he was planning. The decree of Napoleon III limiting all forms of mechanical transportation to a maximum speed of 120km/h was at one level frustrating but against this limitation the need for faster schedules was addressed by locomotives designed to deliver high acceleration and capable of maintaining speed on inclines.
What was needed was the best of both words. The power and acceleration coupled with high speed running.