BR Standard class - practice and performance

but 1000 hp changes quite a lot

 

Testing of one member of one class hardly constitutes a general policy when designing the Standards though, does it?

Unlike most of the Standards, the Brits were a new design, which then sired the Clans and 71000. The only other really new class was the 9F, all the others were modified versions, or straight repeats of, earlier types.

 

If we look at the graph from Britannia constant steaming 36000 lbs/hour fed 5600 lbs of coal by two firemen it can be judged that mean value is 1900 horsepower.
The peak of 2250horsepower last 1.5 mile at over 1900 and is then followed by much less because boiler has to recover.ShortPeak values are worthless for railroads

 

Within the limits of adhesion a short peak is precisely what you do need to accelerate your train, the tricky bit is following it up with a sustained decent output when the fires shot through and the injectors have to go on.
Timing that effort to get you over whatever obstacle to a better place is part of the amazing skill and poise possessed by steam loco crews past , and present

 

OK
I have no driving expirience.
My only footplate ride was on a Heissler along The Pacific in Tillamook,OR. Very nice.

 

A Heisler is a low geared logging tractor of a locomotive with a maximum speed of about 8mph. But what it lacks in speed it also loses in looks. Not much like a Brit.

 

further to my earlier reply to your post , the memory kicked in .
the standards were designed to have the ability to exceed their nominal power class by I think 50% . I may be corrected on that number ………………

it is fair to say they all achieved that although 71000 made us wait.
possibly the most impressive is the 75XXX| which came within an ace of trumping the Black 5 and the 73XXX when tested at high steam rates .

 

True in the strictest sense, however from the cynical viewpoint, it rather depends on who's doing the testing .... and why.

 

Who was trying to fool whom?
I love stories of technical fraud.

 

Merely a generalised observation. Pure scientific method should eliminate bias ..... in theory, at least, but you don't need to look too far, in any direction, to see the sort of conclusions which can be based on the most innocuous of data.

... and I did say it was a cynical viewpoint.

 

I'm intrigued by this, and wonder if you can provide a source for this information. Throughout the years, the many Drawing Offices struggled to fit a quart into a pint part; to get the required power output from the new loco while not exceeding the maximum axle loading or, in the case of the later and larger engines, the loading gauge. Many a design had to be pared down to this end, and paid the price in short durations between works visits. Thompson's L1 was an example of this. So how exactly did BR's DOs manage a 50% - or even 25% - overload power output and stay within the parameters?

 

I will try to find a source .
I have seen this written in more than one place , but just mentally logged it as "interesting" as you do .

 

Yes, I know the feeling.

 

I do recall Coxey saying something along the lines that the standards we're intentionally overboilered and set up with low grate limits, (which in some cases made them die on you rather too easily from over firing) as this was considered to give the best economy from everyday working and longevity of components. As a result there was the potential to overclock them for short periods by 'thrashing' them or for longer periods by re draughting them ( ie double chimneys)... but +50% seems a bit extreme.

 

There is a group of people that regard the Rugby/Swindon tests as utterly suspicious. I have been critisised for using the test data as valid input for my version of the exhaust momentum equation.
What are your opinions?
kind regards
Jos

 

That sounds awfully nice for a dull summer afternon.Who,Why and where to read?

 

What the testing stations did was gather data in numerical format, which must then be interpreted by the technicians. I have some experience in doing this, but in the motor industry, and the interpretations from one person to another can vary, sometimes by a lot. The main problems are with the peaks and troughs well outside the norm, usually revealed when the numerical data is transposed into graphical form.

What the testing stations did was to eliminate many of the variables: train resistance both rolling and aerodynamic, and slight fluctuations in gradient and curvature, and so on, so gave a more accurate presentation than the humble dynamomter car could manage. But it couldn't eliminate the human element.

 

tend to agree with that …. not all tests obviously , but I don't understand why they could get no more than 1850 dbhp from 46225 followed by 2250 ish out on the line

 

that does sound familiar

 

A Br Standard what if
So, Its 1955, the government is feeling flush and decides its going to roll out electrification over the next 20 years and until then steam gets a reprieve.
Theres a bit more Money to spend on Building more Steam locos/ keeping others running; what happens next ?
All in all regional types
1) Hengist #1(the original) gets built with a double chimney, A 250 psi boiler and Caprotti Gear and Run off against a double chimney Std 5.
Result a) Caprotti 5s get double chimneys, All Clans and the First batch of Brits are recalled and rebuilt along the lines of Hengist#1
Result b) No more clans are built
2) 71000 Gets its Kylchap and is run off against Peppercorn A2
Result a) the Brit Boilers from 1) get recycled to make the Duke class.
Result b) thoughts turn to rebuilding Merchant navies/ more Ivatt Duchesses/ Peppercorn pacifics.
3) Further batches of Std 4's in all guises are built a s required to replace older classes
4) Work is stepped up on Dmus and Light Diesel Locos to work branches which dont justify electrification