Question About Mallard
- Thread starter BigBoyFan4006
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BLACKWATCH
Mechanical Engineer
Well I've searched through my library of railway literature, including the 'History of the LMS' by O.S.Nock & a vast volume on the
locomotives of W.A.Stanier, Nowhere is there any mention or photo of a 'Princess Royal' class on the ECML at Stoke Bank in 1953.
Now if this alleged speed run had taken place, O.S.Nock would certainly referred to it, even if he had to note it as 'only a rumour'.
As for the so called record runs by US loco's, even the 'US Trains magazine' won't back the claims .......................
http://en.wikipedia.org/wiki/LNER_Class_A4_4468_Mallard
locomotives of W.A.Stanier, Nowhere is there any mention or photo of a 'Princess Royal' class on the ECML at Stoke Bank in 1953.
Now if this alleged speed run had taken place, O.S.Nock would certainly referred to it, even if he had to note it as 'only a rumour'.
As for the so called record runs by US loco's, even the 'US Trains magazine' won't back the claims .......................
http://en.wikipedia.org/wiki/LNER_Class_A4_4468_Mallard
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jadebullet
might be back?
I still say that the record is not officially held as running on a downward grade disqualifies it from an official record due to an assisting variable. Also, there is a class of German steam locomotives that regularly ran at about that speed in regular service and though since it was mainline service and not some publicity stunt, noone bothered to officiate it.
As for the T-1 locomotive, it is unknown what speed it could attain as the engineers would not push them past a certain limit. In any case, the US had trains that would regularly be pulling freight in excess of 90mph as an operational speed, so to say that there is no possibility that they could have exceeded the limit is just kidding yourself.
In any case, what locomotive actually does hold the speed record if you actually take into account that by record standards the Mallard is disqualified, and the rumored record breaking is unofficial?
As for the T-1 locomotive, it is unknown what speed it could attain as the engineers would not push them past a certain limit. In any case, the US had trains that would regularly be pulling freight in excess of 90mph as an operational speed, so to say that there is no possibility that they could have exceeded the limit is just kidding yourself.
In any case, what locomotive actually does hold the speed record if you actually take into account that by record standards the Mallard is disqualified, and the rumored record breaking is unofficial?
I believe that if you discount runs doen hill then this German loco holds the record.
http://en.wikipedia.org/wiki/DRG_Class_05
http://en.wikipedia.org/wiki/DRG_Class_05
jadebullet
might be back?
No, it matters. If they would have shipped the Mallard to the US and ran it down one of our steeper grades, it would have achieved an even higher speed because of the way that physics works. It is also less impressive when you think about the fact that the UK rarely ran trains above 90mph, and in getting to this speed, the stress of it caused the bearing to overheat, whereas in other places in the world, such as the US and Germany, our mainline steam locomotives regularly ran in excess of 100mph.
But yeah, there is a reason why land speed records are made at the Salt Flats, and not, say, straight down Pikes Peak.
As for the whole inaccurate milepost thing, I call shenanigans. You can't just make some blanket statement that the US doesn't have accurate mileposts, and that we just placed them haphazardly, because that is highly inaccurate. It depends on the road, as well as what type of trackage it is. A branch line, yeah, I can see them being off. I highly maintained, well groomed mainline with carved stone mileposts? I am pretty sure those were as accurately as possible.
But yeah, there is a reason why land speed records are made at the Salt Flats, and not, say, straight down Pikes Peak.
As for the whole inaccurate milepost thing, I call shenanigans. You can't just make some blanket statement that the US doesn't have accurate mileposts, and that we just placed them haphazardly, because that is highly inaccurate. It depends on the road, as well as what type of trackage it is. A branch line, yeah, I can see them being off. I highly maintained, well groomed mainline with carved stone mileposts? I am pretty sure those were as accurately as possible.
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jadebullet
might be back?
That doesn't make any sense. What bearing is related to braking? Certainly not a bearing attached to a crank used in the center cylinder.
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2995Valliant
Well-known member
It is widely accepted that the main reason for the big end failure on Mallard was caused by the driver having to shut off steam rapidly so he could apply full brake as they were rapidly running out of track. It's also widely accepted that 130mph would have been possible given a long enough, straight enough bit of track such as might be found more easily in the US.
The other point to make is that the gradient on down Stoke bank is only 1:178 to 1:200 - so not actually very steep. With only 6 coaches behind any assistance from the downgrade would have been negligible compared to the effects of wind resistance.
Gresley obviously thought a higher speed was possible as another run was planned in 1939 but prevented by the outbreak of WW2.
Incidentally the comment regarding the mileposts in the US was made by an American, the editor of the US magazine "Trains", so he probably had a fair idea what he was on about.
hth,
Anthony
The other point to make is that the gradient on down Stoke bank is only 1:178 to 1:200 - so not actually very steep. With only 6 coaches behind any assistance from the downgrade would have been negligible compared to the effects of wind resistance.
Gresley obviously thought a higher speed was possible as another run was planned in 1939 but prevented by the outbreak of WW2.
Incidentally the comment regarding the mileposts in the US was made by an American, the editor of the US magazine "Trains", so he probably had a fair idea what he was on about.
hth,
Anthony
jadebullet
might be back?
Just because one guy makes a blanket statement, doesn't make it true.
As for the downward grade, it is still a variable and has to be factored into the equation, no matter how "negligible" it is. It isn't widely accepted that 130 would have been possible, it is widely acceptable that it might have been possible, just like it is widely accepted that it might have been possible that a US loco, or German loco beat the record.
As for the downward grade, it is still a variable and has to be factored into the equation, no matter how "negligible" it is. It isn't widely accepted that 130 would have been possible, it is widely acceptable that it might have been possible, just like it is widely accepted that it might have been possible that a US loco, or German loco beat the record.
Further, the A4's were well known to be well able in good conditions @90mph to stop in 1,250 yards out of a signal block of 1,300 yards.
Also certain examples of the A4's had speed recorders in the late 1930's.
Some members were also known the to regulary exceed 100+ mph on some runs.
apparently, Driver Bill Hoole, had an attempt at beating Mallard's speed record in 1959 just before his retirement when on a special trip permission was granted by the CCE to temporairily raise the speed limits to a maximum of 110mph south from Stoke. Driver Bill Hoole had reached a maximum of 112mph just beyond Little Bytham before being prevailed on by the Fireman, Alan Pegler and Chief Inspector Bert Dixon to ease off. The Locomotive was fitted with a speed Recorder at the time.
Frankly, as far as I care, the fact that only Mallard's run out of all the attempts was done with a dynamometer car gives Mallards run the only official creditability as having achieved 125mph.
Also certain examples of the A4's had speed recorders in the late 1930's.
Some members were also known the to regulary exceed 100+ mph on some runs.
apparently, Driver Bill Hoole, had an attempt at beating Mallard's speed record in 1959 just before his retirement when on a special trip permission was granted by the CCE to temporairily raise the speed limits to a maximum of 110mph south from Stoke. Driver Bill Hoole had reached a maximum of 112mph just beyond Little Bytham before being prevailed on by the Fireman, Alan Pegler and Chief Inspector Bert Dixon to ease off. The Locomotive was fitted with a speed Recorder at the time.
Frankly, as far as I care, the fact that only Mallard's run out of all the attempts was done with a dynamometer car gives Mallards run the only official creditability as having achieved 125mph.
I quote from the "The Book of the A4's" by Peter Coster.
"The overheating was probably caused by the regulator being closed for the flat curve at Essendine, while working at full power at 125mph, with the sudden removal of load through the piston and connecting rod. Adolf Wolff of Borsig had three similar big end failure in similar circumstances with his O5 class 4-6-4's, and instructions were given that the regulator should not be closed completely at speeds over 160kph (100 mph), and that the drive should use increased braking instead."
"The overheating was probably caused by the regulator being closed for the flat curve at Essendine, while working at full power at 125mph, with the sudden removal of load through the piston and connecting rod. Adolf Wolff of Borsig had three similar big end failure in similar circumstances with his O5 class 4-6-4's, and instructions were given that the regulator should not be closed completely at speeds over 160kph (100 mph), and that the drive should use increased braking instead."
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It wasn't so much of a lack of straight enough track, it was more that the CCE had scheduled a track possession on the up main at Grantham and had imposed a 20mph TSR.
jadebullet
might be back?
I am not denying history, and I fully believe that the locomotive went that fast, but I am just saying that if you take the record and match it to the guidelines for breaking a record, which were obviously much looser back then, then it doesn't abide by the rules for making a land speed record.
As for the cause of the bearing breaking, I stand by my statement of that having nothing to do with the braking system, and more to do with the regulator being fully closed at such a high speed. That, in its own way, is a design flaw, but one that is difficult to alleviate, similar to how a rotary poppet valve gear runs into an issue at 100mph plus where the springs aren't powerful enough to close fully at that speed, but if you make them more powerful, then you run into issues when it is at lower speeds.
Also, we had locomotives with speedos as well, though they weren't as common.
But yeah, that is why in listing the Mallard's record, the downhill grade is also listed most of the time, where as the German record is listed as a level grade, especially because the Mallard only beat the German record by 1mph, which can probably be attributed to the downhill grade.
As for the cause of the bearing breaking, I stand by my statement of that having nothing to do with the braking system, and more to do with the regulator being fully closed at such a high speed. That, in its own way, is a design flaw, but one that is difficult to alleviate, similar to how a rotary poppet valve gear runs into an issue at 100mph plus where the springs aren't powerful enough to close fully at that speed, but if you make them more powerful, then you run into issues when it is at lower speeds.
Also, we had locomotives with speedos as well, though they weren't as common.
But yeah, that is why in listing the Mallard's record, the downhill grade is also listed most of the time, where as the German record is listed as a level grade, especially because the Mallard only beat the German record by 1mph, which can probably be attributed to the downhill grade.
jadebullet
might be back?
European steam is pretty cool, especially German steam.
BLACKWATCH
Mechanical Engineer
Whatever, it was still a European loco and that's all that matters for me. Just something to actually cheer about in Europe.
It's not "European", it's English.
The German loco had 43 tons less to pull than Mallard, and whilst the line was virtually flat where the German record was achieved, it came after a section of 15 km of downgrade. So undoubtedly Mallard was the fastest, but only by the smallest possible margin.
Kennilworth
Active member
Hi
This seems to have become a bit of an argument when there is only one fact in all this. Mallard achieved its record with a dynamometer car immediately behind the tender and it was this that recorded the maximum speed.
As far as speedometers were concerned, in the UK they were usually driven off of the rear driving wheel on a locomotive. As driving wheel diameters would vary between locomotives due to the tyres being re-profiled when in the shops for overhaul, the speedometers would just be a good guide to speeds but they would not be as accurate as the instruments in a dynamometer car. Similarly the power of locomotives in the same class would vary slightly depending on how many times the cylinder liner had been bored out. It was not unknown for a 3 cylinder locomotive to leave Doncaster works with three slightly different cylinder diameters. I assume similar practices happened in other countries.
Source: The eighteen volume series "The Locomotives of the LNER" published by the RCTS.
Regards
Brian
This seems to have become a bit of an argument when there is only one fact in all this. Mallard achieved its record with a dynamometer car immediately behind the tender and it was this that recorded the maximum speed.
As far as speedometers were concerned, in the UK they were usually driven off of the rear driving wheel on a locomotive. As driving wheel diameters would vary between locomotives due to the tyres being re-profiled when in the shops for overhaul, the speedometers would just be a good guide to speeds but they would not be as accurate as the instruments in a dynamometer car. Similarly the power of locomotives in the same class would vary slightly depending on how many times the cylinder liner had been bored out. It was not unknown for a 3 cylinder locomotive to leave Doncaster works with three slightly different cylinder diameters. I assume similar practices happened in other countries.
Source: The eighteen volume series "The Locomotives of the LNER" published by the RCTS.
Regards
Brian
The German steam record was achieved with a dynamometer in the consist on 11 May 1936 - 124.5 mph with 197 tons.
However the fastest speed ever achieved by the German loco with an equivalent load as Mallard (~240 tons) was 116 mph. So the German loco was not faster with a lighter load and 9-10 mph slower with an equivalent one.
However the fastest speed ever achieved by the German loco with an equivalent load as Mallard (~240 tons) was 116 mph. So the German loco was not faster with a lighter load and 9-10 mph slower with an equivalent one.