Indication of LNER Pacifics

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drmditch
NER C7 4-4-2
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Indication of LNER Pacifics

Post by drmditch » Sun Sep 02, 2018 7:38 am

Several sources refer to No.251 Humorist being indicated in June 1931. I think I have read that this was the only time a Gresley Pacific was indicated.
RCTS 2A fig.56 shows her with shelter fitted. (This was before the various smoke deflecting experiments on this locomotive.)
There is also a web picture of 251 at speed with shelter in place, but I can't seem to find the link this morning.

O.S.Nock 'Gresley Pacifics' page 117/8 has Indicator Diagrams from these runs which are quite fascinating.

The same book (page 38) has a photograph of 1471 with a shelter in place dated 3rd September 1922.

Does anyone know of any results from the 1922 tests?
Also, were any of the LNER Pacifics indicated post-war?

Obviously, an A4 would be impossible on-the-road, but was anything published from Rugby?

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greenglade
GER D14 4-4-0 'Claud Hamilton'
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Re: Indication of LNER Pacifics

Post by greenglade » Sun Sep 02, 2018 12:41 pm

Hi drmditch....

You may find the book titled 'Locomotive Testing on Britain's Railways 1901-1968' by Dave Peel of use? It gives a list of all the tests at Rugby...from what I can see an A4 was only there the one time for the opening in 1948. 60007 Sir nigel Gresley being the loco in question. The only reference that I can see re -indicator trials' is that Rugby adopted an electrical system as developed at RAE Farnborough for testing piston-driven aero=engines, called the 'Farnboro' indicator. This did away with the need for shelters.

under the NER/LNER dynamometer car section, there is a comment stating
'During 1939, the LNER was busy developing the cathode ray oscilloscope method of electronic indicating (with A4 pacifics in mind), and trial runs were made to test this equipment. These concerned class A1 and A3 locos running from Newcastle to Edinburgh, and a k3 2-6-0 together with 4-6-0 1699 (ex-761) as counter pressure locomotive) between Darlington and York'

There's probably more info within this book's pages which covers the various Dyna cars and testing stations...

Regards

Pete

drmditch
NER C7 4-4-2
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Re: Indication of LNER Pacifics

Post by drmditch » Sun Sep 02, 2018 5:50 pm

Thank you Greenglade.
I had seen a reference to the pre-war development of CRT technology for indication, but couldn't remember where.
I've now found it in Peter Townend's 'LNER Pacifics Remembered', in the section by D R Carling, formerly of the LNER Locomotive Testing Section.
(Page 65).

The link to the picture of Humorist in 1931 is .... here.....

There is also a picture of the V2 that was sent to be 'sorted out' after being inflicted with a 'self-cleaning' screens in the smokebox ....here....

If surviving the indicator diagrams would be interesting, although I have seen it stated that that the valve events on that locomotive suggested it was in terrible condition!

I'm sure that somewhere I have seen diagrams for LMS three and four cylinder locomotives, which also show differences between LH/RH/Inside cylinders and forward and backward strokes.

I will look for the book you mention. If anybody got round to indicating the Thompson and/or Peppercorn locomotives the results might provide an interesting comparison with those from Humorist.

I wonder what measurement equipment is built into Tornado?

Hatfield Shed
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Re: Indication of LNER Pacifics

Post by Hatfield Shed » Mon Sep 03, 2018 1:12 pm

drmditch wrote:
Sun Sep 02, 2018 5:50 pm
...If surviving the indicator diagrams would be interesting, although I have seen it stated that that the valve events on that locomotive suggested it was in terrible condition!

I'm sure that somewhere I have seen diagrams for LMS three and four cylinder locomotives, which also show differences between LH/RH/Inside cylinders and forward and backward strokes...
Hopefully most here are aware that in intensive operation of steam locos the beautiful valve events of an ex-works loco are 'happy thought'. With wear in the valve gear linkage, carbon build up on ports and valveheads, liners shifting in cylinders, angular position of the gear affected by both mean and varying axle position in motion (and even maladjustments by fitters who hadn't kept up to speed) the valve events on a loco pounding along several hundred miles a day were apt to be pretty 'deviant'. But this of course was the upside of the steam loco, even mechanically neglected it would get the work done, at a cost.

drmditch
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Re: Indication of LNER Pacifics

Post by drmditch » Mon Sep 10, 2018 11:16 am

Thank you Hatfield Shed.

Yes the valve events in 'running condition' would vary from those initially designed. From what I have read different opinions about the amount of expansion to be allowed for on the middle cylinder existed throughout the LNER's existence. Although it is difficult to believe that, having built so many V2s, Darlington would have continued to have different practices to Doncaster. Obviously the build up of carbon in ports would have a considerable affect. Was some of the experimental work done by the oil companies and railway chemists aimed at mitigating this?

I believe that 'Jubilee' oil contained a higher percentage than usual of rapeseed oil.

However, locomotives did need to be designed, and many design establishments did use 'indication' to give them some feedback on how the design worked. This is why I find it interesting that the tests on Humorist were apparently unique, and I would be very interested in whether 1471 was actually indicated in 1922.

I know that Gresley was not particularly concerned if the centre cylinder was not bored/lined/rebored to have an identical i/d to the outside cylinders.
What I find interesting about the 'Humorist' diagrams published by Nock is that there only small differences between the forward and backward strokes.

I will continue to look for more diagrams and test results.

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