Flying Scotsman

Given the approx. size of the single Mixing chamber required coupled with the flare of the diffuser I cant see that a well proportioned Lempor would need anything other than a noticeably wider chimney to accommodate it. However although it somewhat contradicts the Porta / Wardale creed, a less than ideally proportioned lempor, or more probably kylpor might still offer a more effective solution than the original arrangement. I await with interest the study that the Gurus formerly known as 5-at 's are undertaking with the Clan Project that covers this very dilemna

 

Suprisingly Holcroft does not specifically mention his own derived drive for 3 cylinder locomotives. Intrestingly wear in the valvegear pins is dismissed as easily rectified by rebushing, not so easy under wartime and post WW2 austerity conditions

 

Uneven exhaust beats are not a restriction on steaming, some three cylinder compounds had the low pressure cylinders set at 120 degrees. The designers wanted the most even torque since these designs generally worked on mountainous routes, they steamed well enough by contemporary standards, had to given the work expected of them. The sound that they made was, different.

One of the biggest issues is lack of height available due to the UK loading gauge. If things keep on heading in the direction that they have been over many years we might have to consider the Port of Par twins for mainline running. Yes, rather extreme, but it makes a point.

There is only so much that you can do with the chimney before it starts to look wrong. Within this you have your diffuser exit area with an optimum included angle of less than 12 degrees, ideally 10 - 10.5. Those that have read the theory can yawn now. Below the diffuser you have the mixing chamber, length to diameter ratio 2:1. The chimney overall length to mixing chamber ratio should be in the order of 5:1. You have the limit of the loading gauge as one fixed point, the other is your blast pipe tip. Your tip area increase over that of the original is most valuable, you are wanting reduced back pressure. The ability of the exhaust to create a better vacuum using exhaust steam containing less energy overcomes losses through the spark arrestor system, boiler gas flow, combustion system resistance.

The Theory is readily available, so are details of the Gresley Pacifics. Have a little play, you will get some idea of the problems.

 

Interesting video on FS trip down under… the most interesting thing is 4.27 onwards salt and steel really don't mix well!!!

 

In view of the intricate knowledge, and presumably patterns etc, accumulated by Riley's during their overhaul of 60103, is it not now time that we considered a "new-build" A3?

In true LNER tradition this would, of course, be merely a" general repair" of a long-scrapped loco, provided that the new loco carried some part of its predecessor, such as name/works plate, whistle, pressure gauge etc. (which must exist in private collections), and would therefore assume the identity of that loco. I would like to propose the third incarnation of 60090 (LNER 2744) "Grand Parade" for starters!

Double Kylchap, smoke deflectors and GN coal-rail tender, please.

I understand that the "Grandad's Axe" principle is also applied in the restoration of historic aircraft.

 

I seem to recall suggesting a new-build A3 some time ago, leaving the "real" 4472 to be immaculately displayed at the NRM. A good working replacement could be any one of the class but "St Simon" the last A3 at Grantham Shed, would be a nice choice if it were mine to make.

 

Surely there's enough leftover worn out parts from all the overhauls over the years to construct a static replica?

 

I suggested that, the should have saved all the broken knackered bits until they had enough!

 

Ah, but which would be "the replica" - the static one built from all of the original (worn out) parts?
...or the working one built from all of the totally new parts?!

 

"Great Northern", as it should have been.

 

Or with the amount of money already spent on it. Just build a new one. Stick 60163 on the side and Scotsman nameplates and joe public wouldn't be the wiser.

 

60163?? That's a bit of a Freudian slip! I hope you meant 60103.

Foxy.

 

Maybe we could have one in BR condition and one in LNER to keep everyone happy....

 

How about in BR condition but LNER livery? Oh hang on a minute....

 

Yep, that would be quite authentic - for the 1990s

 

Well it shouldve read 60164 ;-)

Slip of the finger. Smartphones are not my friends. Carpenters fingers (or whats left of them).

 

Ah but how long would it be before there were strident calls to restore the A3-shaped pile of worn out bits to steam...?

 

The LNER was a railway company. They existed in order to make a profit for their shareholders. In order to do that, they ran trains.

Why on earth would they have stopped, in 1945, to worry about 4470's "historical significance"? She was only 23 years old. Her designer had only been dead for four years. Why should anyone have stopped to think about whether the she would be considered worthy of preservation 20 years in the future?

If Thompson had pulled Stirling No. 1 out of York Museum and started making alterations, perhaps then we might be a little more critical. But 4470 was still a working engine in 1945. So, did Thompson's rebuild turn her into an engine that better suited the needs of 1945? Did it ultimately deliver good value for the LNER's shareholders?

I don't claim to know enough to be able to answer those questions - but I firmly believe that these are the only questions by which Thompson and the rebuilt 4470 should be judged.

The same applies to Charles Collett for the rebuilding of The Great Bear. An almost identical scenario, yet Collett doesn't seem to attract nearly as much wrath as Thompson does :-S

Another point to consider is that even if 4470 had not been rebuilt, she probably wouldn't have been preserved. Silver Link was arguably just as important, but she still slipped through the net - as did the equally-important Silver Jubilee coach sets, for that matter.