Tornado

York to Newcastle would be fine, its thrown it down the past 2 days.

 

Postponement rather than cancellation - Tornado is due to visit next Easter.

Tom

 

Wasn't there talk shortly after the incident of both DBC and the RAIB having an interest in this incident and preparing reports?

 

I note that Steam Railway have published an edited version of my original response (for which I am grateful for the opportunity to air my views).

I note that David Ward has responded to Graeme Bunker - again.

I am considering my response and will likely send it direct to the magazine for comment, rather than post it here.

However I will express my exasperation at David Ward's repeated claim of "50% overloaded". There is an inherent flaw in his reasoning and I rather suspect he knows that - but likes to grab headlines still.

C'est la vie.

Thank you SR for publishing my letter.

 

Mr Ward perhaps is of the same opinion as Oscar Wilde "the only thing worse than being talked about is...not being talked about"

 

I don't see how speed can't be ruled out as the reason for the failure,What do you expect to happen to non lubricated metal at speed ?
Seems to have been showing off for showing offs sake and its come back to bite them,lucky it didn't cause further issues which might have harmed other mainline steam in being out on the mainline,

 

We've been through all that before: the basic cause was a lubrication failure to the middle valve chest, and seizure would have resulted irrespective of the speed. It wasn't a cause, any more than A1s were regularly seizing their valves in normal BR service at similar speeds.

 

As there has been no official report published yet, should your post read "the assumed basic cause"?

 

Nothing to do with showing off, you are obviously not a trust member or you would know the reason they are passed for higher speed. The A1 Trust have specifically ruled out speed as being a factor, they have all the data from the incident and their Director of Engineering is Dave Elliot, a graduate professional engineer andEx BR traction engineer , your qualifications are?

 

Ive read that that was the cause? Plus LMS2968 tends to know his stuff

 

You could be right, but thinking about, the Trust might simply have included it in a list of possible causes rather than state it as definite, as I thought. But there's a lot of thread to read through to check. It's still where my money would be, though.

 

Well, I know very little of A1 maintenance, but a Ford x-flow engine will seize just as happily at 1800rpm as 6000rpm if your dry sump gets a bit too dry. I rather suspect that whatever fate befell 60163, it would have happened at Mr Ward's nice safe 59mph just the same

 

I'm trying to understand what is meant by "overloading" a steam locomotive. It is not possible to overload it in the same sense as a traction motor, where too much current will overheat the motor and burn out the insulation. For a steam locomotive, at first sight, if the load is too heavy it will just slow down. Possibly what is meant is that, if the locomotive is working hard, you can build up a very big fire which produces a very high superheat temperature which can then affect the valve lubrication.
Does this make sense?

 

Have a look here, and it is very easy to join the dots, and see the issue centre's around a lubrication delivery failure, then consequential damage.

https://www.a1steam.com/category/news/

As for the comment about "showing off", grow up, there are enough WUM's in the world without another one.....

 

I would say he has a degree in trolling.

 

I don’t think a big fire necessarily equates to high superheat temperature. The temperature of the furnace gases as they emerge from the fire is hotter than the superheater steam, but is limited by the chemical composition of the coal - burning more coal increases the amount of gas produced, but not the temperature of that gas beyond a certain limit.(*)

Raising the temperature of the superheated steam is a dynamic, not an equilibrium process, i.e. the factors are the temperature of the firebox gases (which don't increase beyond a certain limit just by burning more coal); the length of time that each gas can flow through its respective tube; and the mass of gas to be heated. Under high demand, you have a higher mass of steam flowing through the superheater. Because the pressure is constant, it must be flowing faster, i.e. spending less time flowing through the superheater. So higher mass of steam to be heated spending less time in the superheater - that suggests to me that at very high demand, the superheater temperature should drop.

(*) In other words, at peak combustion efficiency, more coal = more gas at the same temperature, not the same amount of gas at a higher temperature. As a thought experiment, imagine a 50sq ft grate area firebox burning coal at its peak rate. Now split it longitudinally into two 25 sq ft grates - the combustion on each side is unchanged, so the gas temperature remains unchanged, but each side is only burning half the coal in half the air flow, and producing half as much gas, but at the same temperature, as before..

Tom

 

If 'Overloading' affects any part of a Steam loco. the steam circuit isn't it, its the 'engine'. Usual behaviour which your average steam loco copes with is the highest force applied whilst standing/low speeds, lower forces generally being applied at speed. Tornado is probably the only loco to have been driven at 40%+ cut off at 80+mph for generations, but on paper she should also be the loco best prepared to handle that.

 

I would suggest that any overloading of the mechanical parts is more likely to be in the power transmission area: pistons, little and big ends, coupling rod bushes, axleboxes. It's far less likely to be in the valve / steam chests, especially if the gear is linked up to give only a relatively small amount of valve movement.

 

So there's a few parts to this.

1. Train overloaded. David Ward makes the claim that 12 coaches, 24 bogies, is overloaded by making a comparison with the A4 streamlined trains pre-second world war, which were 8 carriages, articulated with less bogies.

The logic follows that less bogies equals less rolling resistance. No argument there.

The coaches used on the Silver Jubilee, as an example, were lighter - 280 tonnes from memory - Tornado's Ebor Flyer was 417 tonnes, 12 carriages, 24 bogies.

So David argues, reasonably, that this is around 140 tonnes heavier and double the number of bogies potentially. Therefore the rolling resistance is in theory higher on the Ebor Flyer.

So you would think, this is reasonable.

Except...

He states in his second letter "despite any advantages from roller bearings on the modern carriages" which actually is something of a significant advantage where the Ebor Flyer is concerned.

So is this comment from Mr Ward - ignoring the more modern roller bearings and lowered rolling resistance - fair to the A1 Trust and what actually happened?

Further...

2. David also argues in his first letter that the Peppercorn A1s were designed for hauling 500-600 tonnes of train at 60mph.

So if we re-examine what he says in point 1, and remember that the Ebor Flyer was 417 tonnes of train, whether at 60mph or 90mph, is well within the Peppercorn A1's theoretical capacity.

Throw in that the original A1s were pulling 500-600 tonne loads of coaches which were normally not articulated (in their lifetime, new Thompson coaches plus the Mk1s were not articulated - and there were only a few articulated sets on which they would have been rostered) and that the rolling resistance of the LNER and Mk1 vehicles was higher than the Mk2s and Mk3s plus the single Mk1 support coach.

Does that comment about being overloaded still seem fair?

Which is it? Was the train overloaded or not?

Also...

3. The Peppercorn A1 not being designed for 90mph.

Ludicrous.

Thompson designed the rebuilt Great Northern to be the "post war A4". He knew that. His draughtsmen knew that. The drivers knew what the locomotive was capable of.

Peppercorn took over. He didn't set out to design a locomotive to pull trains at 60mph. It was the new post war A4, developed not from Thompson's A1/1 but along the lines of the successful A2 he had developed from Thompson's A2/3.

***

I feel that the answer is more obvious and more likely than the speed factor.

I will not pre-empt the official report but I have every confidence in the A1 Trust to make public their findings and satisfy all of the regulatory bodies together with anyone else who would like for their own piece of mind, information that may be relevant to their own charges (such as anyone running a similarly set up machine such as a Bulleid Pacific).