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Evening all,

 

If any of you have ever seen any of my layouts and models you'll know that I model industrial railways and normally I would have posted this in the UK Standard Gauge Industrial section of RMweb but I thought that there may be more people who would appreciate this, and have knowledge of the prototype, here.

 

About 10 years ago I picked up an original 1927 copy of A.R. Bennett's book "The Chronicles of Boulton's Siding" and I have always fancied building a model of one of the ancient and eccentric wonders in the book. I'm going to have a go at building Isaac Watt Boulton's No.11, which was originally a Sharp Roberts 2-2-2 passenger tender loco and was bought from the LNWR on 1st of March 1866. It may have orginated with the Liverpool & Manchester Railway and was probably built in the 1830s.

 

As far as I am concerned No.11 does count as an industrial loco as Boutlon hired his engines out to railways and contractors. What makes it interesting to me is that he rebuilt it with smaller wheels and converted it to a saddletank.

 

post-494-0-04405900-1510779484.jpg

 

I have a set of 4mm scale bodywork and fittings castings for a standard Sharpie tender loco from 5 and 9 models as a basis on which to start but I am going to have to build a running chassis from scratch. So, the first question is did these ancient outside-framed locos also have another set of frames on the inside of the wheels? I'm sure I have read somewhere about things like this having inside frames so as to give more bearings for the crank axle in the days when they were prone to breaking due to metallurgy not being so advanced at the time.

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Based on the well tanks on the Furness Railway, plus sight of drawings for other engines of this wheel arrangement, I can offer the following.

 

The rear carrying wheels are only carried in the outside frames - this keeps the springs and their mounts away from the firebox, keeping the wheelbase down.

The front carrying wheels are (usually) also carried only in the outside frames, for the same reason with respect to the cylinder block.

It is important to keep these carrying axles as close as possible to the firebox and cylinder block to keep stresses down on the frames.

The middle, driving, wheels are supported by both the inside and outside frames, with axleboxes either side of each wheel. Early GWR broad gauge engines also had a fifth bearing, in the middle of the axle. (There was room!)

The inner frames ran above the outer axles, if they reached that far.

 

Now the fun bit... Where did the inner frames begin and end? Think of them as being the braces to the belt provided by the outside frames. These latter are the main structural component of the locomotive, as everything else is fixed relative to them. But the role of the inner frames is to support the power unit, i.e. the cylinders and the crank axle, plus valves and eccentrics. As such, the inner frames have to begin by being bolted/riveted to the cylinder block, and must go beyond the driven axle. Since they will need joining together, (or keeping apart!) then a spacer of some form will be needed beyond the reach of the cranks and connecting rod big end, in addition to that provided by the motion bracket (which is also quite possibly supporting the mid length of the boiler). This will have to go in front of the fire box.

 

On the drawing you have, the bottom of the inner frame is quite clear between the leading and driving axles, but there is no indication of this besides the firebox. It is likely that both the inside and the outside frames supported the buffer planks at the front, but only the outside frames at the rear: it is also likely that there was no footplate in front of the cylinder blocks.

 

The outside frames may well have been a sandwich with thin plates either side of a substantial thickness of wood, necessary due to the fact that the high quality steels which rendered this unnecessary lay some years in the future: the Furness engines had outside frames composed of 5/16” plates sandwiching timber of 3 ⅜”, or 4 in total. You could easily cut the outside metal frame from 5 thou sheet and emboss it to represent rivets, and sweat it onto a piece of 1mm or so metal.

 

How much of this you actually follow is up to you. It is perfectly possible - and a lot easier - to build a working inside framed chassis, and to make the outside frames cosmetic. I know I would, and having done it once the same way as the prototype, so would the best modeller I know!

Edited by Regularity
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There is a good drawing of a Stephenson 2-2-2 here https://www.flickr.com/photos/[email protected]/36834175885/in/photostream, just for interest. This shows inside frames running from the front of the firebox to the front buffer beam. There are no front axles, if the drawing is correct - the leading wheels being independent assemblies running in inside and outside bearings.

 

There is a good photo of a Sharp 2-2-2 converted to a tank engine here - slightly different to yours but with similar features. https://en.wikipedia.org/wiki/List_of_early_locomotives_of_the_London_Brighton_and_South_Coast_Railway#/media/File:CVHRsharp222.jpg

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Off hand I cannot think of many Loco types that had stub axles, Winan's did on some in the States.

The weight of the loco would stress the outer frames to much, without the full axle, which keeps things stable.

Stephen.

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With the second drawing I would suggest it was the drawing simply not showing the axle for simplicity. If the drawings are usual type done in the Engineer, they are rarely works drawings, and often the engraver took liberties with details.

Also a serious point, the wheels would barely remain in gauge without the solid axle, as the wooden frames flexed a lot. A solid axle checks the wheels in gauge all the time, and aligns the bearings, spreading the forces more evenly.

Stephen.

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No. 11 certainly was an odd duck, I'll be watching this progress with interest, the LNWR converted a few of its sharpies to saddle tanks, I beleive I have a photograph somewhere

Thanks for posting that photo. It appears that there isn't what we would know as a running plate, as on more modern steam locomotives, just a gap between the inner and outer frames that is open where there are no springs, toolbox, splashers etc. I'll see how that compares to the castings.

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Thanks for posting that photo. It appears that there isn't what we would know as a running plate, as on more modern steam locomotives, just a gap between the inner and outer frames that is open where there are no springs, toolbox, splashers etc. I'll see how that compares to the castings.

you're very welcome, I do have another photo somewhere which shows another such loco from the front which I'll try and dig out for you

Edit: here we go from the January 1960 railway magazine, note the ornamental chimney cap which no. 11 also had

sharpie_zps7winbs71.jpg?w=480&h=480&fit=

Edited by Killian keane
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I prepare to stand corrected but think what the drawings show is the early practice of rigidly fixing the rear end of the inner frames to the firebox - thus making the boiler a structural member whose differential thermal expansion relative to the inner frames was a source of stress - of the mechanical sort. The implications of this weren't well understood at first, so it wasn't a source of stress to footplate crews although occasionally fatal. It took a while - perhaps until the late 50s/early 60s? - for it to be realised that full-length inner frames with the firebox supported on slides was a much, much better arrangement.

 

Boulton's lowering of the frames (by reduction of the wheel diameter) appears to have left the buffer centre-line above the top of the frames, which must be a further source of weakness. There would be a considerable turning moment applied to the buffer plank when buffing up hard and conversely when pulling hard - how is the drawgear arranged?

 

Further H&S anxiety arises from Killian keane's first picture - that shovel is going to swing back and deliver a nasty blow to the engineman.

 

Interesting early LNWR carriages, though. Any idea of dates for the photos?

Edited by Compound2632
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I prepare to stand corrected but think what the drawings show is the early practice of rigidly fixing the rear end of the inner frames to the firebox - thus making the boiler a structural member whose differential thermal expansion relative to the inner frames was a source of stress - of the mechanical sort. The implications of this weren't well understood at first, so it wasn't a source of stress to footplate crews although occasionally fatal. It took a while - perhaps until the late 50s/early 60s? - for it to be realised that full-length inner frames with the firebox supported on slides was a much, much better arrangement.

 

 

I was at the museum at Penrhyn castle the other week, and was wondering how the Dinorwic loco 'Fire Queen' coped with boiler expansion. It has no frames, with the boiler acting as the main structural member. I guess the answer is 'not very well'
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There is a good drawing of a Stephenson 2-2-2 here https://www.flickr.com/photos/[email protected]/36834175885/in/photostream, just for interest. This shows inside frames running from the front of the firebox to the front buffer beam. There are no front axles, if the drawing is correct - the leading wheels being independent assemblies running in inside and outside bearings.

 

 

Someone mentioned the inner frames not being full-length but in the engraving in the above link they go right up to the buffer planks at the front (and, presumably the cylinder block is bolted to them) but at the rear it's not possible to tell as the outer wrapper of the firebox and the footplate are shown covering whatever is under there. They are wider than the uncovered part of the firebox, so would I would assume that they were full-length and they either supported, or were bolted to, the firebox.

 

Regarding the front axle, I agree with Bertiedog that the drawing doesn't show it for simplicity. In fact if you look at the enlarged verision you'll see that the inner end of what is shown as a stub axle is roughly drawn, which would suggest that it should really continue.

 

I have the castings.

post-494-0-24562000-1511027249.jpg

The outside frame parts are cast with a top plate, which I'm not sure whether to remove or not. At the smokebox end it fits into the smokebox casting, so at least part of it will have to remain. I will have to remove the splashers and make new ones to suit the smaller wheels.

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Things are not exactly going to plan with this.

 

I decided to scale the drawing to 4mm so I could measure up the saddletank and to make sure that I had got the finished size of the drawing right I put some of the castings in the scanner and scanned them to the same dpi as I did the drawing.

 

The length and height of the frames match but the axle spacings don't. Another problem is the smokebox/cylinder casting. As you can see it is of a greater overall depth than that on the drawing, which means the boiler will end up being higher and the gap between the rail tops and cylinder block will be smaller.

 

post-494-0-66538800-1511711758_thumb.jpg

 

I don't know if the drawing is wrong, the castings are wrong, or even if the original locomotive prototype was different to the prototype that the castings are intended to build up into, so I can't decide whether to just go with the castings as they are, or to have to do a lot more scratchbuilding than I expected.

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You could try the opposite and stretch the drawing to the same size as the castings. That might work. Otherwise, it may well be that the drawings in the book are essentially reasonably well-proportioned sketches. Personally, I would be pleased but surprised if the drawings in the book were to exact scale.

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You could try the opposite and stretch the drawing to the same size as the castings. That might work. Otherwise, it may well be that the drawings in the book are essentially reasonably well-proportioned sketches. Personally, I would be pleased but surprised if the drawings in the book were to exact scale.

I don't understand how stretching the drawing will help. My picture shows the scan of the frame casting superimposed on the drawing; the length and depth of the frame casting matches the drawing. It's the spacing between the middle and rear axle that is different.

 

If I stretch the height of the drawing to match the smokebox casting then everything else, including the depth of the frame will be out.

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Or thinking a little off beam - you have pointed out that the rear axle frames have had to be reinforced, as evidenced in the drawing.

 

Is it possible that the axle was moved a few inches inboard when the mods/strengthenings were made to reduce the flexing in the frames?

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As I suggested before, I think it would be wrong to take the Boulton's Sidings drawings as accurate. I doubt the information was available to do that - and the absence of a scale on most of them points that way too. There are one or two exceptions, like the broad gauge 0-4-0T in fig 57, which I feel sure I have seen a scale drawing of elsewhere (possibly The Engineer?). In the frontispiece and at the end of the book, the original author suggests that many drawings were produced from faded photographs or sketches from memory where no photo existed. Looking through the book, the photos are of poor quality. Most photos are angled to show a side and an end., so guessing exact dimensions for things not quoted in paperwork must have been an educated guess, at best. Look at fig. 44, for example, and compare the locos shown with the drawings quoted on p155, as figs 25, 65 and 4. Maybe the drawings represent these locos at different stages of their careers, but there are quite noticeable differences nevertheless.

 

If you are really keen to do a credible model, I would find a good drawing of the original locos and adapt it to suit. The wheel diameters in the book ought to be reliable and Boulton's other enhancements can be approximated from the Boulton drawing. If the castings aren't right then you have a choice of either using them and adapting the design, or sticking to the design and making new parts.

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Never trust old drawings, often wrong in detail, but overall correct to accompany a book, pamphlet, or The Engineer. Ahrons simply took many of his republished drawings from old sources that bore no dimensions at all.

If it look a right to surviving photos, it probably is as accurate as your going to find, bar going through works drawings in the NRM, and even then there legends of errors.

One of the worst offenders was The Engineer, whose engraved drawings are magnificent art, but are often wrong.

We forget that Steam engines were the equivalent of rocket science to Victorians, the engravers did not understand complex steam engines.

The Engraver would not specialise in the early days, his daily round might have been Punch or The Illustrated News. The illustrations were drawn out by the contributor, who then employed the engravers.

I is perfectly obvious that some engravings were sized to fit the format of the printing plates as well.

 

Best course with Victorian locos is to work from the middle outwards, say on a single assume the driven axle is correct, and work away from that datum, keeping proportion in mind rather than exact dimensions.

Stephen

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On the smokebox front casting, it looks like there is a bit of excess material in between the top of the cylinders and the bottom of the smokebox door. Could this be cut and shut to reduce the height?

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