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PostPosted: Tue Jun 27, 2017 12:57 am 
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Joined: Tue Oct 13, 2015 9:33 pm
Posts: 7
Location: Waikanae, New Zealand
This is a first post from a newbie, so please bear with me if this ground has been covered in the past.

My question relates to the effect on LNWR locomotive cab side sheets when the distinctive "turn-ups" of the company's "pagoda" cab roofs were modified, from the late 1920s, to more of an arc profile to conform to the LMS composite loading gauge. I have attached a rough sketch, hopefully to make my question clearer.

The LNWR traditional cab side sheet has the elegant reverse curves at the top and bottom of the beading. It seems to me that, if the roof "turn-up" is cut back, the reverse curve at the top of the side sheet would be lost, imparting quite a different "look" to the side-on appearance of the locomotive. Is that correct? Does it vary among locomotive classes?

I have studied photographs and drawings (the latter mostly to 4mm/ft scale). Photographs, when the top of the side sheet is not in shadow, appear to show both loss and partial retention of the upper reverse curve. Drawings seem to have a bob each way.

Although my query was prompted by plans to upgrade and modify a couple of Gem Precursor/George V locomotive kits to mid-1930s condition, I thought that it fitted under a more general Locomotive than a Modelling heading.


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PostPosted: Fri Jun 30, 2017 4:34 pm 
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Joined: Fri Feb 12, 2010 9:49 am
Posts: 192
Location: Edinburgh
Hello Mike,

As far as I remember this subject has never been discussed in detail in the past, and I'm afraid I simply do not know exactly how the LMS made the alteration.

From photographs and larger-scale drawings it clearly wasn't simply a matter of cutting off the overhangs beyond the side-sheets; it looks as if the entire cab roof was new, with presumably an altered (or new) front weatherboard. I would assume the side-sheets remained as they were, but could well be wrong, so hopefully someone can give us the facts from an LMS drawing.

Harry.


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PostPosted: Fri Jun 30, 2017 9:20 pm 
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Joined: Tue Oct 13, 2015 9:33 pm
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Location: Waikanae, New Zealand
Thank you Harry, you've put your finger nicely on what has been puzzling me. The terms "cut down" and "cut back" imply a simple "chop job". But, if the rather pronounced curvature of the central portion of the original LNWR cab roof was simply continued down to the side of the cab, the side sheet would be lowered by more than six inches, and that obviously didn't happen. That implies a completely different shape to the arc of the cab roof, so therefore a replacement cab roof and even a new cab front.

This does reinforce how difficult it can be to get an answer on what might seem a simple matter once those who did these jobs at Crewe and elsewhere have passed on.

Our skilled etched kit designers may have addressed this small mystery in the past.

Mike


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PostPosted: Sat Jul 08, 2017 10:11 am 
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Joined: Tue Oct 13, 2015 9:33 pm
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Location: Waikanae, New Zealand
There's a lesson here. As soon as I ask a question, I'm bound to find an answer staring at me.

In relation to a modelling project, I was looking at the section in Volume Two of Jenkinson and Essery's "Illustrated History of LMS Locomotives" which covers the ex-LNWR 0-8-0s. On page 109, Plate 243 gives a close-up of the modified cab of a Belpaire G2a. The side sheet is clearly still in its original form with the reverse curve at the top still in place. That 's good enough for me for the "Super Ds" at least.

By contrast, the photographs of the two "Georges" (LMS nos. 5401 and 25348) on pages 24 and 25 of the same volume don't seem to show any reverse curve remaining at the top of the side sheets of the modified cabs.

So, different locomotive classes, different solutions, (or maybe different foremen in the sheet metal fabrication workshop of different works over the decade during which the modifications were made!)?

A related question: what is that strange circular object that interrupts the rain-strip on the modified cab roof of the G2a in Plate 243 referred to above?


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PostPosted: Sat Jul 08, 2017 4:25 pm 
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Joined: Sun Feb 07, 2010 7:33 pm
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Location: Deep in the Dordogne, Commune of Loubejac
Isn't it where the secondary (train alarm) whistle would have been fitted? You can see the same fitting on other classes in E & J, although not such clear detail.

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PostPosted: Sat Jul 08, 2017 10:04 pm 
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Joined: Tue Oct 13, 2015 9:33 pm
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Location: Waikanae, New Zealand
Thank you David. That is most probably the answer. I was aware of the train alarm whistle on unmodified cabs but hadn't realised that it was still in use at the time that cabs were modified - or had simply failed to use my eyes when perusing photographs for other reasons.

By chance do you know when the use of the secondary whistle ceased?

Mike


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PostPosted: Mon Jul 10, 2017 11:45 am 
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Joined: Fri Feb 12, 2010 9:49 am
Posts: 192
Location: Edinburgh
According to L&NWR Eight-Coupled Goods Engines, written and published by Edward Talbot in 2002, this ring on the cab roof was to accommodate the steam heater relief valve - when fitted.

This is mentioned in the caption to plate 208 on p157 (the photograph is the same as Jenkinson & Essery's plate 243). It seems that only a very few of these engines were actually fitted with this valve.

Harry.


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