Why weren't the Standards standard?

I think that's a misinterpretation. One of the drivers behind the 47s seems to have been that for all its disappointment on passenger trains the Bear had been very good at running fast fitted freight. It seems to make more sense that the 47 was always intended to have a high capacity boiler derived from the Bear flanging blocks, but the original plan as per weight diagrams in RCTS 9 was for the boiler to be used on Stars and Saints as well. Cook tells us that the Std 1 boiler was fitted because the Std 7 'could not be completed in time'. This sounds odd, but it seems to me that perhaps the delay was fundamentally that the drawing office were trying to design a boiler that would provide the desired capacity and make the weight limit for the Star. In the end Collett elected to commission new flanging blocks for the upgraded Star and build a slightly smaller diameter barrel on the Std 7 firebox, and that was the Castle. In the meantime one assumes the Std 1 version of 4700 provided an extended trial to chassis features like the long fixed wheelbase.

 

The largest new, different, components were the wheels, cylinder and saddle assemblies and the front extension frames. I think these were all manufactured more than a decade ago.

Standard cylinders were cast from a set of standard patterns put together to suit the smokebox diameter and boiler pitch, so that the resulting finished castings were not generally interchangeable between classes.

Hence new cylinders for 2999 (giving the opportunity to use the earlier inside steam pipe design) and some rather dubious (?) jiggery pokery to fit a no 7 boiler to the replica 4700.

 

William Dean was even more enthusiastic about standardisation than Churchward. He developed three standards each of which superseded the previous one!

First developments of George and Joseph Armstrong's existing inside framed designs with a new domeless boiler built in different lengths.

Then a series of 0-6-0 and 2-4-0 tank and tender designs with identical cylinders and wheels and only slight variations in boilers.

And finally a series of 8 wheeler designs developed from the convertible 2-2-2 express loco he designed for the final gauge conversion, though with a multitude of boilers, some to fit between large driving wheels and others of new designs he allowed his chief assistant to experiment with.

Whereas, in contrast, Churchward developed one standard which lasted for 3 CMEs and beyond.

 

Thanks for that information, although I must say that I'd have had more to say about manufacturing new cylinders and saddle than I would have the wheels (even the Hairy Bikers have cast loco wheels) I take it that the Std No 7 boiler for the Night Owl is larger than the Hall, 28xx, etc. boiler (Std No.1?) which is being used on Lady of Legend?

 

No.7. Boiler compared to No.1. - both are 14'10" long but 7" larger diameter at the smokebox, 1' longer in the firebox, nearly 20% larger total heating surface, and has a 12% bigger grate.

 

So the No.7 is the larger of the two? and was used on the 47xx 2-8-0? was it used on any other class?

 

The No.7. was only used on the 47xx class - a total of only 9 engines which, at face value would hardly make it standard hey?? However, there was a plan to shoehorn it onto the 28xx's, saints and stars. It could not be made to work due to weight restrictions on the six coupled locos and would have placed route restrictions for the 28xx's. Collett also wanted to use the No.7 on the castle but also had weight problems with it. So it was designed as a standard with several applications in mind but practicalities made it impossible.

 

Swindon standardisation (meaning the use of identical components on more than one class of loco) is certainly relevant to some of the other projects, notably 4709, which is incorporating parts from more than one donor loco. But AFAIK pretty well all the parts for Lady of Legend have either come from the single donor Hall or been manufactured from scratch. If anyone knows different, please say.