Scotsman overhaul by Dr Marchington

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Percybigun
NER Y7 0-4-0T
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Joined: Sun Feb 05, 2017 5:02 pm

Scotsman overhaul by Dr Marchington

Post by Percybigun » Tue Feb 21, 2017 3:30 pm

I've seen a few dvd's about the Scotsman when it was owned by tony marchington, describing many "go-faster" modifications included during the overhauls. Whilst the famous double kylchap blastpipe and chimney was tried and tested during the LNER/BR era, surely the other mods would have been by Gresley and his successors but were not used on the A1/A3. Could the other 'dubious' go-faster mods have contributed to it becoming such a mechanical mess which later had to be sorted by NRM and Rileys? And was the famously mis-aligned cylinder/block a cowboy bodge, cocked up by Marchington's overhaul(s)? I've read a few books about the scotsman and it touched on these subjects, but is a bit vague as to who was to blaim.
Also did the other "go-faster" mods (apart from double blastpipe and chimney) done by Marchington, get removed during its recent epic overhaul by NRM and Rileys?
And because NRM retained the double chimney, does this mean (because of their purist approach) that it is unlikely to ever wear the LNER apple green livery ever again? I had hoped they would alternate the livery, like Tornado's owners do.

drmditch
NER C7 4-4-2
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Re: Scotsman overhaul by Dr Marchington

Post by drmditch » Tue Feb 21, 2017 5:17 pm

There was quite a lot published about this issue a few years ago.

The NRM report is ....here...
You can find more .....here.....
and .... here.....

I can't find the earlier engineering report at the moment. I'm sure I saved a copy of it!
Tracking it from either the NRM website or the 'First Class Partnerships' website doesn't seem able to locate it.!

Some of the problems of operating a 'conventional' plate framed steam locomotive at network speeds are discussed on the A1 and P2 websites.

From memory:-
- the use of the A4 boiler at 250 PSI (most A4 boilers used on A3s were set to a lower pressure)
- the A3 cylinder diameters used were not reduced for the higher pressure, so generating more power than the structure was designed for.
- modern CWR creates quite different stresses in plate frames than the jointed track most locomotives were designed for. The tendency of coned wheelsets to 'hunt' is 're-set' by the track joints, whereas on CWR the hunting will have to be contained by the frame structure itself.
- there were other problems as well.

I will try to look more later, unless someone else on here has a better memory than I do!

The livery question is also contentious! The argument goes:-
- the double Kylchap is needed for reliable fast running on main lines with an unpredictable coal quality
- the exhaust is softer with the Kylchap, so the 'German' smoke deflectors are needed to avoid exhaust clinging to the boiler and obscuring the drivers view forward.
- No A3 ever had Kylchap and smoke deflectors when in LNER Green (except for Humorist - and she had 'A1' shape deflectors).
- Therefore the only 'authentic' livery is late BR green.

However, I do like big engines in LNER green, .....with LNER on the tender.....

Be warned though, this subject can generate enough emotion and strong opinions to pre-heat boiler feedwater!

Percybigun
NER Y7 0-4-0T
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Re: Scotsman overhaul by Dr Marchington

Post by Percybigun » Tue Feb 21, 2017 6:03 pm

Ah so the go-faster mods didnt do it any favours, especially on such an old loco that has had such heavy use. Hopefully bittern wasnt effected by such things when owned by marchington?
I understand why the double chimney is much better for modern mainline use, but the drab livery does have its negatives, whenever its on the tv you can only see the top 10% of the loco, the rest (i.e. The best bit!) is mostly in shade.
I was on a train passing NRM and york station last year, scotsman was parked outside, i was the only person on the whole train who jumped up to photograph it, nobody else on a packed train even noticed it. If it had been in the apple green livery, everybody would have gone mad! But that said, the dark livery has not effected the
loco's huge appeal and popularity since its return. I'm just a bit disappointed to see so many Ex lner and lms loco's in black or dark green BR liveries these days.

pete2hogs
LNER Thompson L1 2-6-4T
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Re: Scotsman overhaul by Dr Marchington

Post by pete2hogs » Mon May 08, 2017 9:17 pm

I'm not sure the 'go-faster' mods are to blame.

First, to what extent was the extra power actually used instead of proividing an increased reserve.

Second, the A3's were notorious (to the works) for needing extensive frame repairs in LNER/BR days, to the degree that a 'float' of repaired frames was in existence and a repaired set would be taken from the pool to speed up overhauls, while the loco's own frames would be repaired and eventually reappear under another class member. Bad news for those who believe a loco's identity belongs to its frames!

So it is hardly surprising that after what, 40 years of maintenance by people not familiar with the type that extensive frame repairs were found to be necessary.

I think the more relevant question is was the work carried out of sufficient thoroughness or was it more of a 'sole and heel' job. Against which it has to be remembered that at the time the loco was private property and the owner was quite entitled to do with it what he wished.

Doncaster had a grand tradition of quietly getting on with work that other establishments might have thought demanded scrapping and replacement of the whole loco - most of the Stirling Singles got through at least two sets of frames, IIRC some got through three sets. And to jump to more recent times, they cheerfully coped with the Deltics and their special needs when nowhere else wanted to touch them.

JonR
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Re: Scotsman overhaul by Dr Marchington

Post by JonR » Tue May 09, 2017 11:13 pm

I just did some maths and that boiler at 250psi and cylinders bored back out to 20" would have given it a TE of 41375lb! No wonder the frames were shot as they were designed for a 29000lb TE for an a1. With a misaligned cylinder too it had no chance.
JR

burnie
NER J27 0-6-0
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Re: Scotsman overhaul by Dr Marchington

Post by burnie » Wed May 10, 2017 9:40 am

I guess those who were around just after the nationalisation remember the locos not in the Apple green, but in the later British Railways colours and therefore perhaps like the idea of the current colour and german smoke deflectors look. Though when the Scotsman was sheded at Leicester it didn't have either the double chimney or the deflectors when I first saw it, the same with the other A3's on the GCR. My take on the line that I am currently starting to build as a model, has the "Flying Fox" in Brunswick Green, but with a single chimney and no deflectors to accurately reflect the period I intend to re create for the 1958 - 1963 period when the loco was allocated to Leicester.

Hatfield Shed
LNER P2 2-8-2
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Re: Scotsman overhaul by Dr Marchington

Post by Hatfield Shed » Fri May 12, 2017 6:04 pm

JonR wrote:
Tue May 09, 2017 11:13 pm
I just did some maths and that boiler at 250psi and cylinders bored back out to 20" would have given it a TE of 41375lb! No wonder the frames were shot as they were designed for a 29000lb TE for an a1...
Underlying this is that whatever the tractive forces, UK plate frames simply could not be made strong enough within the limitations imposed by weight restriction, to cope with the power potential of a wide firebox design. The Doncaster team did class leading work in their day - which is not often recognised - in successfully squeezing the quart of power output potential onto a pint pot worth of structure. A pacific frame - compared length for length - was no heavier than that of a 4-6-0, yet the pacific format has the potential to sustain double the continuous power output thanks to the much increased grate and ashpan area and larger superheater area it makes possible. Twice the work going into a gven weight of frame brings inevitable consequences.

A certain M. Chapelon was very eloquent on the limitations imposed on European steam designs due to this restriction in weight (which of course affects quantity of metal in frame structure) and looked enviously Westward to a land where axleloads significantly exceeding 30 tons were permitted thanks to investment in route structure and heavier rail sections. Cast steel one piece frames and cylinders...

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