Sir Nigel Gresley - The L.N.E.R.’s First C.M.E.

With little blips on?

Tom

 

Ha!

 

It's something that we quite rightly concern ourselves about but, back in the day, it would have been an everyday occurrence, perhaps not from 126 mph but from speeds in the 70's, 80's & 90's and the effect would have been pretty much the same. The water may well have been mortgaged to obtain the record speed which may not have been the norm but even that would have been something that the crew took in their stride as not every journey was text book and fighting to keep time with the water in the bottom nut wouldn't be unusual. One thing we enginemen never know is what the true water level over the firebox is as, once it's out of sight, we have lost that indication. The water level in the glass is also always lower than the water over the firebox because it isn't boiling.

 

Having studied the roll again last night (then slept on it, then checked again today):

• Between milepost 91 and 90, Mallard does around 125-127mph (as a range)
• From milepost 90 and a half, steam is shut off and the gradient goes from down the 1 in 2240 to up 1 in 550.
• By milepost 89 and a quarter, speed has reduced to 118mph
• By milepost 89 the speed is 110mph
• By milepost 88 and a half the speed is 106mph
• By milepost 88 and a quarter, brakes have been applied and the speed is now 95mph
• By milepost 88 the speed is 83 mph
• By milepost 87 and a half the speed is 71mph
• By milepost 87 the speed is 69.5mph

So from milepost 91 to milepost 87 the change in speed is about 55mph over the distance covered (4 miles).

Hope that is helpful Tom.

 

Thanks Simon.

That raises more questions

From the info given, you get the following decelerations:

90.50 --> 89.25 - a drop of ~8mph in 1.25 miles, up a 1 in 550 gradient
89.25 --> 89.00 - 8mph drop in 0.25 miles
89.00 --> 88.50 - 4mph drop in 0.5 miles
88.50 --> 88.25 - 11mph drop in 0.25 miles, "brakes have been applied"
88.25 --> 88.00 - 12 mph drop in 0.25 miles
88.00 --> 87.50 - 12 mph drop in 0.5 miles
87.50 --> 87.00 - 1.5mph drop in 0.5 miles

So firstly it looks to me that the brakes have been released round about 88.75 milepost, since the deceleration gets markedly less. (From 88.50 to 88.00 it is losing 11 or 12 mph every quarter mile; then it takes half a mile to lose a similar amount; and then for another half mile it hardly loses any speed at all).

The other point is what happens right at the start. You'd expect that, in the absence of brakes being applied, the deceleration would be most pronounced at highest speed (because of the effect of drag and the relationship that has with speed). So if you had simply shut off speed and coasted, the train would slow down quite rapidly at first, but then the rate of decrease of speed would ease. But that's not what actually happens: the train loses 8mph in 1.25 mile to start with (presumably just being slowed by air resistance), but then loses the next 8mph in only 1/4 mile. Then it loses only 4mph in the next half mile. That suggests to me that there was some kind of preliminary brake application somewhere round about MP 89.25 (or perhaps a bit before) which was then released around MP 89.00; before the main brake application somewhere around 88.50.

Tom

 

The official purpose of the trials was to carry out brake tests, I think with coaches fitted with quick acting valves. Presumably, the dynamometer car was next to the loco and the 'brakes applied' would probably have been noted by a drop off in vacuum registered on the gauge in the car. The quick acting valves won't drop the vacuum until it detects a reasonable difference between the chamber and the train pipe so it may not have been immediately after 'brakes applied' had been noted. Again, as it was a brake test, and I'm speculating here, it may be that part of the test required the brake to be released and information obtained on how quickly they were released and this occurred around MP87½. A recording of the train pipe vacuum would be a very useful piece of information in considering all this.

 

That's the "tale" I've heard of too Steve. Officially it was to do a "Brake Test" with the quick release/acting valve. With Gresley "requesting/suggesting" that they have a go at the speed record, in an unofficial manner, using the "Test run" as a smoke screen/cover story for the record run.

 

Indeed so. It would be interesting to know what specific instructions the crew were asked to follow with the brake, but it looks to me that they are alternating between brakes applied and released in fairly short order.

Incidentally, at what point did the failed middle big end become known? Was that only after the train had drawn to a halt?

Tom

 

Whatever the technicalities of the run, I would sell both of my kidneys to be transported back to that day and be on board the train. Two 90+ runs behind an A4 were exciting enough but heaven knows what it would have been like at 126.

 

Eric Bannister reported in his book that the stink bomb went off in the 120s. He and Spencer then immediately reported it and the train was slowed from that point.

 

I seem to remember reading that the Westinghouse Team were told that an attempt would be made at the speed record and anyone who wanted could go home by taxi.

None did

 

I think we do have this and I will check when I can and report back.

 

What's interesting is that that doesn't seem to be quite what the speed data you quoted show! Or at least, conceivably Duddington shut off when they noticed the stink bomb, but the subsequent braking wasn't a smooth continuous deceleration down to low speed.

I took your data above (post 1624) and plotted the speed against distance at each quarter mile. Where there isn't data, I interpolated in a linear fashion (for example you gave 83mph at milepost 88 and 71 at milepost 87.5, so I interpolated 77mph at milepost 87.75).

There's a complexity that vac brakes are slow to apply and slow to release, so the response isn't even and also the brake is probably applied before you notice the speed start to slow; and released before it stops slowing down. But even so, it looks to me that the train was braked intermittently. It looks to me like:

• From MP 90.5 when you noted "steam is shut off" to MP 89.25 it looks like the loco is coasting, but without the brakes being applied. (1.25 miles, which would have taken somewhere around 44 seconds).
• It then looks like there was a relatively gentle brake application from MP 89.25 to 89.0, a distance of 1/4 mile which would have taken about 8 seconds.
• From there, it looks to me like the brakes are release again, since from 89 to 88.5, the deceleration is very modest again, about the same as the initial deceleration from peak speed.
• Then from MP 88.5 to 87.5 there is what looks like quite a hard brake application, but which is gradually eased. Finally at MP 87.5 it looks like the brake is released again and the deceleration is very slow. By now about three miles and nearly two minutes has passed since steam was shut off.

From the data you have on the dynamometer roll, I suspect you could plot the speed curve rather more smoothly, and hopefully also correlate with the braking data. But to my admittedly crude plotting, it looks to me that the brakes were not applied initially; then applied gently, released, applied more strongly, and then released again.



Tom

 

Would that be anything to do with the smoke deflector trials Simon?

 

Hi Tom, I agree with you that the account doesn’t match the records - but I am paraphrasing it here, having cited it in my book (and I didn’t trust my memory enough to give more than that when I wasn’t near my laptop to check).

I’ll find the quote and put it here tomorrow so you can see what was said exactly.

 

For sure. Humorist is one of Gresley’s great success stories for the innovations that came out of its testing.

 

Sorry this is so much later. Here is the quote:

I think Tom at a first glance that corroborates your version of events and likely confirms the shape of your graph to be more or less in line with that.

I am still working on the full diagram and statistics for this and will update when I can.

 

Recently I had the opportunity to visit Edinburgh, Sir Nigel Gresley’s birthplace, and I couldn’t pass up the opportunity to visit the two Gresley Society plaques in the city:









I have been reflecting over the last few years of writing, research and more today, with the knowledge my book is heading to the printers very soon.

I became - shall we say infamous? - for my repeated determination to give Edward Thompson a fairer hearing over the last decade. That was originally borne out of a curiosity as to whether what had been written on him was accurate (turns out, no it wasn’t!)

But Gresley has been in my life since 1994. Aged 5, looking up at a black and gold nameplate that read “Flying Scotsman” - railway bug absolutely took hold and has never let go. That was Gresley’s doing, I’m afraid. Everything for me centred around Sir Nigel Gresley.

Books, models, then lectures given at school, university and now given as a genuine (if always learning!) railway engineer.

Why is this important? Well, I set up this thread to discuss rationally the broader aspects of his stewardship as a CME and whether he was any good. My research and discussions have led me to the potentially biased conclusion that yes, I believe he was a good railway engineer and CME. It will be no surprise to anyone I suspect.

I was accused of being fanatical over Thompson and yet, I suspect, with a bit more context to my views, my life and history, one could reasonably work out that my fanaticism is actually, and has been all along, Gresley.

Why does this matter? Well you could argue I’m not well placed to give the most balanced views on him. Something I’ve been considering on and off with some worry for months on end. Is this book actually going to be any good? Does it add to the debate or take away from it? Does it have good evidence, have we picked the right photographs, have I offended anyone unnecessarily, are we being fair to all of Gresley’s compatriots and will the inclusion of a single photograph of DRG 05 002 generate more heat than light? Will it be reviewed well? Does that matter? The list goes on…

Sitting near Edinburgh Waverley observing the LNER Azuma coming and going, I do think it matters. I think it matters because ultimately Gresley has shaped the world around us in a way probably not recognised enough. High speed railway travel in fixed units of trains that allowed business and leisure travel to be more within the realms of reality between the capitals of the England and Scotland.

When alls said and done, I just hope that people can recognise in my work that I worked hard at getting right, even if I ultimately didn’t in their eyes. This stuff matters, dammit.

 

What matters is the man - not his locomotive / carriage designs but the factors that made him the person he was - his family, his friends, his interests, his relationship with staff and his commitment to their welfare and improvement. Most biographies tend to stick to their designs but rarely look at the elements that make a CME the man he appears to those around him. What, for example, was the influences from his wife and her early demise; what comfort did he gain from family and friends in his hour of grief and did such tragedy influence his working relationships ? Hopefully Simon's treatise will cover these points to round out the man whose previous biographies concentrate on his work and ignore the factors which make him the person whose character was universally praised by his contemporaries.

 

I think you will be happy with the overall view, but I must warn that going into the personal life is fraught with the dangers of subjectivity. You will note at the start of the book that a member of the Gresley family has provided the foreword. That will indicate the level to which it has been written.