P2 Locomotive Company and related matters

Someone once told me that the difference between an engineer and a fitter is that when something doesn't fit right, an engineer will reach for a ruler, a fitter will reach for a hammer.

 

That's an old one ... I always cringed when I saw hammer marks on motion gear in them days...in Yorkshire a name for a hammer was a "Lancashire Spanner"..

 

A picture speaks a thousand words, how on earth you could tell its 1.5" out of whack.
Was it manufactured that way, maybe, was it handled incorrectly, possibly, could it have been dropped, dont know......

 

Perhaps the meaning of trapezoidal firebox got lost in translation...

 

Typically, someone possessing the qualifications (formal or through decades of relevant experience) to define machines and structures that meet their requirements with an economic use of material and capital, both financial and human. Not the person who fts your sky dish.

Anyone can build a bridge. It takes an Engineer to build you one that nearly, but doesn’t actually, fall down. Efficient use of resources.


Engineering is a science, but applying it in the real world can become almost artistic, and steam locos are one of the prime examples of this. Learned knowledge in how to fit them up over and over and over again was lost in the 1960s when we stopped making them and make the workforce who were skilled in doing it, redundant.

Every single class of machine will have its own subtle details in how things expand, contract and wear over time, due to the subtle differences in how the chief engineer designed it.

In my book you don’t have to have a degree for me to consider someone a competent engineer, but there has to be evidence of their ability to repeatedly apply the principles and concepts that define what engineering is.

In the preservation space, there are many such individuals who do this day in and day out.

Side point but we don’t protect the title here in the UK and I sometimes think we should.

Tongue firmly in cheek, but it’s definitely someone who doesn’t ask questions like this.

On the boiler being out of square, there must be instances in other mainline locos where this has also happened? Yes they must have welded fire boxes but still…..

Reading the above I’m going to speculate, but this could be an answer to the hypothetical story I’m reading above about the box moving.

Iv harped on about this before, but a fully welded structure like this would be more “stable” (engineering term, mechanically stable due to residual stresses induced by thermal loading) if all the residual stresses were baked out through a full post weld heat treat. It is notable that this is what was done on the cylinder block for the P2. All that welding will distort the structure and every time you skim the bores, it will move and you may end up with ovular bores or worse.

It would be hard to do a full firebox assy, you’d need a big oven, but there is so much heat put in to the structure when welding up stays it would be prudent to take them out. Boxes stayed by threaded stays of course wont have this problem.
Also, thinking about it, what order they are welded up in will play a part in the resultant principal stress pulling on the box in the final article. This could what has happened, under repair, the box has moved because whatever residual stresses were left in the box after initial welding at manufacture, have remained, and distorted the box when the old stays have been cut out.

If say the box was welded up in a pattern in Germany, and then we get to overhaul, and we cut some stays out of one side, that side is now under-supported to counteract the residuals that are present from the still complete welds in the other parts of the box.

It is notable that it was the foundation ring that received a lot of attention, because that is a core anchor point for the box mechanically. Removing it, or sections of it, will allow any residual stresses elsewhere in the box free reign to manipulate the shape.

For those saying 1.5” is a lot, over a structure that big its bang on what would be expected in terms of movement in welded structures like this. There are rules laid down for the kind of distortions over given dimensions possible.

Is there a welding engineer on the board for the A1, or are they using Meiningen to guide them? Its all so easy to see in hindsight, but if it were my call, id really want to heat treat a fully welded box because every time you remove even 1 stay, you are risking distortion due to residuals. Quantifying that risk is a judgment call left to Engineers I highly doubt anyone modelled the boiler with all the residuals in place for FEA, as it would be an enormous task.

Also, if any of this is true, it does beg the question, are the boilers on hold to allow the A1 2nd and P2 boiler to go back to threaded stays…….? How’s that for some speculation…..?

Can anyone point us to where fully welded up boilers have been used elsewhere? That would really help inform this discussion.

 

Forgive me for asking a dangerous question, but if the Trust are now missing David Elliott, was he/were his engineering decisions actually also part of the problem - and hence his absence (and that of his knowledge & experience) a fundamental gap in how the Trust can remain sustainable ?

 

Not a dangerous question at all. David Elliott also advised a number of other new-build groups (the G5 is one that comes to mind immediately) - how have they succeeded him and also, in what form did his "brain dumps" take as regards the P2, and to whom?

 

Thats a very interesting post W.Williams. I don't know enough of the process of Welding, but it's plausible.
We also don't know what 1.5" out of square means precisely (at what temperature? In which direction? With or without tolerance?).

As you say boxes have been welded before, but does anyone with the craft oversight (ie not the designer or the blerk with the welder, but the foreman/chargehand etc) remain?

I suspect one of the problems the new boss has is that he is used to a staff below him. Within reason he says "go this way", and subordinates ensure they have men and tanks etc in place, and their subordinates organise the details. Here, there isn't that size of staff, so matters of engineering detail need to be managed at a higher level.

Hopefully, this sort of questionning is going on behind the scenes, but I'm not at all convinced.

 

I do know what CNC is....but what about a machine, that's where CNC comes into use. CNC machines have to be guarded to ISO 14120:2015 so there's no real need for PPE, apart from ear protectors if you're machining some types of exotic material. Where I served my engineering apprenticeship, I built one of the first punched tape NC machines in the UK. It was destined for Crewe works....

 

I am also thinking of Tornado, the choices made there, and the role of experience even where everything was perfectly documented and handed over.

 

Indeed. There have been many on this thread lamenting Mr Elliott’s passing, and blaming all of Tornado’s ills on that unfortunate event, but no-one has actually suggested anyone as a suitable replacement. It’s sometimes very easy to point out a problem, it takes a different skill to find the right person to fix it.

 

No we don’t, that detail is missing, it does all appear to be speculative, so I thought id throw in some speculative hypothesis grounded in some engineering fundamentals just to give a possible explanation.

Its important to remember, this is not unusual. Engineers make decisions on evidence, but it can sometimes be the case that in service, new evidence emerges and the decisions made in future need to be subtly different. Happens all the time. Comet and square windows anyone…. Ford and they current Wet Belt system is surely going to be another…

Taking a step back, now there exists 10 years of running experience with Tornado, and a wealth of experience on the overhaul of the boiler, it would be a very "brave" (insert your own adjective of choice here) move not to revisit some of the design detail of the boilers that are now on order. Very brave indeed, because if you saw the same distortion issues twice, on two different machines, over 20 years of operating life, you’d have an incredibly difficult time defending the decision.

Is this a question about if using CNC machines makes you an engineer? At a minimum being able to program and operate one makes you skilled, no doubt about that, but only using a CNC and nothing else would not, I feel, be enough to qualify as an engineer. Its application of many principles over time, in my view. Interesting that one of the first went to Crewe, was that under BREL?

 

Well I started out with my apprenticeship with fitting machine tools. Scraping slideways, fitting taper strips of all types, onto building a complete lathe. I was then put through the entire machine shop, turning, milling, planing, precision grinding, gear cutting et al and then drawing office, planning office etc. I consider on reflection to have been very lucky....

 

As these A1 boilers were made in Germany, surely the discrepancy is 38.1mm?

 

If my memory serves me right, when the boiler design was handed to the German manufacturer, sorry can't remember the name, they were not happy about the water space between the inner and outer fireboxes, I think German designs preferred a larger water space between the inner and outer fireboxes.

 

It would have been in the late sixties....we had so much snags with it, I recall, my company offered to buy it back, but Crewe refused... I think there was some sort of Government involvement with it. Hydraulic servo motors and I think Moog servo valves...fun days..
Your remark about FEA had passed my mind, interesting...does anybody know if this happened ? As you say it would be very complicated ...

 

In my work life my job title was Site Engineer.
I was responsible for all technical details for a Plain line track renewal.
I was involved in Planning and design of the renewal and on the night I ensured that the track went in to specification controlling the diggers and tampers and then it was my signature on the Track handback form saying it was fit for 90mph.

My Father in Law was titled as a Resident Site Engineer, but he was S+T and the Selby Diversion was his last major job.

A friend of mine back in the 90's was an Engineer with ICI looking after plastic film for crisp packets.

Engineers come in all sorts of fields but can they do each others speciality?

 

The original meaning of engineer was broadly "one who builds/manages/operates engines". At that point engines were engines of war, ie battering rams/siege towers and the like. This then moved into design and construction of siege works (as guns meant traditional castles were less useful, the master mason got elbowed out). From there we got "civil engineers", as they built civil works.

Engines became shorthand for "mechanical things" (see the Halifax engine...). Probably the US use of "engineer" as "one who drives the engine" is probably closest to that.

Given you even have "software engineers" now, there is arguably no requirement for physical manipulation of materials at all.

(Then in, eg the MF/1 or FIDIC forms of contract, the engineer is the third-party in the contract responsible for allocating extensions of time and costs, which is arguably a different skill-set again.)

I think these days engineer means "got a job but not an arts degree...".
[Edit: There should be a smiley face there, don't know where it went]

 

I'll try anything still to this day...my brain still works, I think, but the chassis is creaking. I'm currently doing work on 3D composite fibre manufacturing.

 

Isambard Kingdon Brunel says "yes"
Daniel Gooch says (under his breath) "not as much as you think, hat-boy"