News from JLTRT

Dog Star

Western Thunderer
Just for the record... what was done to that loco which resulted in the 47 having a "banana-boat" appearance?
 

Dog Star

Western Thunderer
The upper bodyside rails are, ahem, missing?
Fair enough Steph. So what you are saying is that the stress calculations for the body shell include a contribution from the bodyside structure... I believe that the BT4s did not have a stressed skin so what was the internal structure which has been removed here?
 
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Steph Dale

Western Thunderer
Graham,
Have a look at this link https://flic.kr/p/rkYVtT which helpfully shows a Cl47 with one side removed. This would seem to indicate what you say; actually after posting I realised the same. However there must be some strength in the upper bodyside or roof as every photo I've found of a loco with cut sides and engine in place has a failed frame. It's also true to say that the cab crash frame would be structurally pretty useless (which it isn't, even if the level of protection it offers is far from ideal) if there wasn't some way of transferring load along the upper body side, over the doors. So there must be a rail of some form at, or above, the top of the bodyside.
It'll be interesting if someone can come along with the definitive solution.
Steph
 

mickoo

Western Thunderer
Fair enough Steph. So what you are saying is that the stress calculations for the body shell include a contribution from the bodyside structure... I believe that the BT4s did not have a stressed skin so what was the interenal structure which has been removed here?
All of it!

Class 47, like many others are monocoque construction and rely on a complete box (or in BR locos cases a trough) type affair for strength, imagine a girder bridge, then cut out the top main beam :cool:

However the 47 frame is also strengthened in the engine area for the very reasons Steph notes above, no high level integrity above the engine room access door. The floor drops down for two reasons, part of it is to depress the engine to get it inside the body, two to add extra strength.
IMG_2872.jpg

The chamfered section is the depressed engine room floor, not the internal walkway as that remains level but the floor is lowered to accept the engine, the box girder section below that adds extra strength to the floor to support the engine and add strength where high level longitudinal steel work is reduced.

On the Class 56 the engine is slightly smaller and there is no side door, those bodies have a thick beam at high level where the roof panels fit onto. Class 56 basically use a Class 47 body with some modifications.

The reason the loco in Stephs view hasn't collapsed is because the engine has already been removed so there is very little weight there.
 
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Mr Grumpy

Western Thunderer
Hi Mick,
Great detail photo of the underframe!
Don't suppose you have a photo of one in original condition as per IKB when built you could share?
How can one person know so much about diesel locomotives both sides of the pond???
 

mickoo

Western Thunderer
Hi Mick,
Great detail photo of the underframe!
Don't suppose you have a photo of one in original condition as per IKB when built you could share?

Hi, afraid not, this is one of the later Freightliner modified ones, as you've already spotted.

I only have one shot of IKB, York, probably 80-81
47 484_York.jpg
Other than the colour, ETH fitting, blanked headcode and Serek radiator shutters, the rest is pretty much as built.

How can one person know so much about diesel locomotives both sides of the pond???
Simple, I'm a sad git who has nothing better to do than sit on my fat backside and browse the web for research ;) Seriously, I only know so much about particular locos that interest me, which isn't really that many, class 33 and class 50 I know jack all about nor really care about.

The Class 47 arrived at Felixstowe to be taken away for scrap, it had sat in Ipswich yard for years slowly rotting away until it was in such a bad condition Network rail basically banned it from ever moving, it kind of achieved cult status locally. There's no facilities at Ipswich to load to road so a special train was eventually formed to move it to Felixstowe where we put it on a truck for scrapping, that's why it has a air pipe hanging out of the front, the loco brakes were shot so it was temporarily through piped and placed between a Class 66 and a freightliner train.

I only know so much about 47's as I crawled all over this one for underframe details for my MMP 57....which lurks under the bench awaiting my return.
IMG_5269.jpg

I decided to make a full underframe, fish belly engine room floor and strengthening plates for the tanks as well as full 3D drag beams and other major beams, bit crude by current standards mind.
 

richard carr

Western Thunderer
Well it looks pretty good to me and I know the final version will be spot on.
I'll certainly be buying one but more likely 2 or 3

Richard
 

Dog Star

Western Thunderer
Pete, I agree with Richard... the external appearance is what is so critical with diesels and that is where the effort needs to be spent. A more interesting question might be "what about the shape / detail / accuracy" of the underframe as highlighted by Mick? I think that Mick has a point about the depressed part of the BT4 and as the position of the fuel / water tanks is relative to that lowered frame then Mick is correct to (try to) model the overall impression.

regards, Graham
 
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