Leaderboard

There is a photograph in Jim Russell's book 'GWR Wagons Appendix' that shows a wagon loaded with long, thin conifer tree-trunks, of the kind referred to as 'Norway poles'. For some time I have wanted to model a similar load. The wagon itself has been described in this blog before, and has a rather chequered history. Amongst other issues, I put washer plates on the inside, corresponding to the attachment points for the sheet supporter mechanism at each end. I was following the RCH drawing for the sheet supporter parts, which was the only information I had at the time; since then, I have seen photos that show the GWR didn't put washer plates on the inside. I therefore wanted to add a load to hide the washer plates I had put in, so this was my opportunity to model the Norway poles. Making the poles has been a slow process - 15 months in fact. They are made from the twigs of a Christmas tree, with the needles stripped off and most of the bark sanded off. I collected all the suitable twigs from our 2022 tree, but there weren't quite enough, so I had to wait until the 2023 tree became available. Each time, I left the twigs for a couple of months to dry out, then stripped the needles and sanded then with coarse sandpaper. The remaining texture gives a reasonable impression of the partly-stripped bark seen in the prototype photo: The bottom layer of poles was glued to a piece of stiff card about two-thirds the length of the wagon. More poles were glued on top, and the final layer left loose, as I wanted to ensure there was no glue visible. The roping follows that shown in the photo, and is made with 0.75mm rigging thread, as used by ship modellers - the same technique I have described in previous blog entries. A small amount of thin cyanoacrylate glue holds the knots in place. And here with a 2-plank wagon as a runner: Nick.

With all the running repairs completed for now, I couldn’t resist putting a few items of stock on the layout before putting it away for the time being. I’ve a list of jobs to do before Wells, including finishing off stock items so I’ve filled my display case with items requiring attention, just to remind me. Some just need lamps, crews and coaling. Some need motors! Next up will be the fiddle yards. photos attached The prairie is heavily reworked Lima with Comet chassis The Collett Goods a reworked Replica with High Level chassis 5757 is a Bachman pannier with a High Level chassis 4694 is rewheeled Bachman Pannier The twin rail car a Worsley Works etch on a cut and shut Replica chassis all are detailed in my other tinking table blog.

I have finally finished the first B set for Cheddar. Little did I know that this was going to be quite so involved when I started, what now seems a very long time ago. The origin was a set of sides, roofs and ends from the Ks kit, kindly given to me by Tim Venton. These coaches were prevalent in the Bristol division after nationalisation so I was always going to have a set on Cheddar. When it came to start, I’d lost one of the ends so ended up making a blank from plasticard. The sides were glued together and married up to a Comet under frame and Bill Bedford sprung bogies. Under frame detail is a mixture of Comet and MJT. The bogie sides were originally the incorrect 9ft pressed steel type before I swapped to the 9ft fishbelly bogies and added lots of extra step details. I also made the mistake of painting carmine and cream before being corrected and advised that this wouldn’t have been applied to non gangway stock. Easily rectified and painted chocolate and cream to match the photos in Russell. Lining is HMRS. Numbering and end lettering is from Railtec. Seating is Ratio, handles Comet and an unmarked bag of unknown origin. Glazing… Hmm. This was individually flush glazed with perspex and yes it did take an age but I’m out of therapy now. I’m never, ever doing this again. Thank goodness for Rapido’s E140/5. I’ve an E129 and E147 to do from Comet kits but at least they’re brass. Whether I’ll ever use the shawplan extreme etching flush glazing on the Airfix b sets remains to be seen. At least they’re pre-cut. These coaches have taken over a year to complete and yes there are plenty of things I could have done better. Apart from some weathering they’ll have to do for now.

Dave the welder has run out of big bits to weld..... We are now at the stage of where we now have lots and lots and lots of fiddly small parts that need to be sorted out, and if you watch something like car SOS this is where the time gets eaten up..... The drivers side window getting much attention after more rot was found in the corner, the lower window frame and shelf have been replaced with metal. Another view of the shelf, some quite complex fabrication was required to recreate this. towards the side the shelf has to curve in correctly Awaiting final cutting the whole area of new metal is etched primed to protect it from corrosion. There have also been significant issues found with the door frames and at no1 end the corrosion was so bad it would have prevented proper fitment of the doors, so it has been cut away and replaced with fresh steel. The steel here is 6mm thick so it can be tapped to hold the hinge bolts for the cab doors. Similarly on the other side the door frame was completely rotten its and the cab grab rail recess have been replaced with new steel. below that the door threshold has been replaced and this will form part of the outer skin of the locomotive. this is prior to having the side skirt fitted. on the other side the side skirt has been bent to shape and fitted giving an idea of how things are being achieved, towards the front original side skirt deemed suitable for re-use has been re-attached, it awaits final welding to close up the join, you cant weld too much too quickly as during welding the metal expands and distorts. the cab grabrail recess base awaits cutting and replacing. the drivers side getting the same treatment, as you can see, if you don't protect the steel with primer...it very very quickly starts to rust. At no2 end the cab desk refurbishment is underway we see the absolute rats nest of pipe work below the desk, the cab desk has been removed as the Formica is life expired, and needs replacing. the Formica has been removed (it didn't take much effort) and this leaves behind the contact adhesive we can see the aluminium desk is pretty badly butchered with years of modifications evident. a solvent has been applied to "clean" the old glue off. the desk has been re-covered with tufnol, which is similar to formica but a lot cheaper and less brittle, the only problem is, that its more susceptible to scratches, and isn't as hard wearing as Formica, the desk is being trial fitted, to determine its correct position. the desk in its final position with the fittings attached, the instrument panel will be thoroughly cleaned, and the gauges given a good clean as well after years of dirt ingress, the gauges themselves were comprehensively overhauled, by a group member many years ago and as a result need no attention and are in perfect working order. The brass plunger behind the locomotive air brake is the brake overcharge valve, as 26s had a yellow band FV4 (valve on the left) they didn't overcharge the brake valve in the release position. Back to the exterior....the part we have been really dreading is the front skirts...they are an extremely complicated part of the bodywork and many discussions have been had with other 26 owners on ways to fabricate these correctly.... the one problem we do have is none of us have legible original drawings....so we are going to have to compromise. the skirt itself is a is a curve on 3 planes....and this is something a skilled panel beater could probably achieve with an incredible amount of time....on an English wheel, but the labour costs quoted would be in the region of 5 to 6k per end. Another way of creating it would be with press, but we would need to create the tooling....which for such a limited amount of panels required wouldn't be viable. the way you see above is actually the way BRCW created them individual sections profiled to create the curve along the base and the front to the middle.....but since we don't have the drawings...and neither do the NRM...we will have to use our gut.....and go with what we think looks right from photos....but every other 26 has the same issue....none of them are the original front skirt....they were all repaired and bodged over the years. above we have the plates tack welded into place...to do some trial and error....fitting after we were happy with the result....they were finally welded.... the welds ground and primed... the process completed for the other side..... and finally the front.....is complete.... the windows have been cut to roughly the correct shape, no doubt some work will be required when the screens go back in, there is also some remedial work needed to the "eyebrows" as well. only 15% of the steel in the whole front end of the locomotive is original steel! the original front end.....nice paint....but its hiding a lot of issues.... the July gala approaches......time is of the essence.. and an old friend is coming back....and there's only one thing better than one 26..........

Here I am again, with the freelanced locomotives on the Broad Gauge. Starting from the beginning how I came to this point, I'd have to tell you about @Annie's 4-2-4T freelance which started it all, and I'm glad for that because it just looked really good that I wanted to build something like it. Seeing how good it looked and it also being in a wheel arrangement I really like, I just had to build something like it. But when I did so, the results were quite... bad? mediocre? I don't know either. Maybe it was my lack of modelling experience at the time, because this was months ago. Looking back on it embarrasses me because of the many things I did incorrect. Or maybe because I just didn't put much effort in it as what I came up with was basically indistinguishable in my opinion. My first mention of it was in this blog post of my freelance designs "Kenstec" Having "improved a lot" looking back on this model just makes me laugh, to list the things wrong with the model, the side tanks are too wide, very wide sander yet no pipework, quite a modern smokebox, also a really wide door. In short, this model is basically old and looks off. Time-skip to today, neglecting and procrastinating all my school assignments due to asynchronous classes, I saw that @MikeOxon posted about his progress with building the Small Pearson Tank in the end bits of the post, he added in his 3d model of Dean's experimental single tank, which I've always found unique and beautiful in how it looked. Too bad it was a huge failure! Having reminisced on my old model, I decided that it was due for a new one. "Great Western" Featuring "Great Western" a new WIP project of mine that basically acts as Dean's single tank but on broad rails. Many parts of this freelance can be seen in real life locomotives such as the 517, Dean Single, Armstrong Class, and some other I forgot about. The process was just me loading in the old file and removing everything except for the wheels, which I turned into real ones instead of just cylinders with colors. Bunch of searching for references later and I think I've almost reached completion since as of now I think I only have to do the brakes, coal bunker and buffers left, maybe some other small details too. Really proud of how this looks like! Definitely a huge improvement if I say so myself.

At the outset, the primary concern of mine was fitting Rospeath Lane v.2 in my car. Rule 1d of the Scalefour Jubilee Challenge stipulates "The layout has to be portable and capable of being transported by a single car or similar size vehicle and exhibited by two people". I'm surprised it dosen't state that both operators have to be transported in the same car as the layout. As a cost saving exercise for exhibition managers, I feel it would be prudent for both operators to travel with the layout. The problem I face is Tredethy Wharf fills my car including the passenger seat. I've been relying on help at exhibitions from friends having their own transport. Also Rospeath Lane's footprint is larger than Tredethy Wharf which means there is more to fit in the car. This is why I've been worried about how I might adhere to Rule 1d. Since committing to the Scalefour Jubilee Challenge, I've almost exhausted the grey cells in working out how to fit Rospeath Lane into the car. I have measured the car boot space and all other nooks and crannies that could be utilised. Then, I spent a lot of time thinking about how to reduce the important clutter around the scenic section of the layout. In this I mean the support structure, lighting frame, control panel, cassette boards with blanking/information panels and tool box along with the all important operators stool for thous quiet moments. The diagrams below hope to show how I visualise it all fitting in the car, including a couple of small overnight bags for multiple day shows. Hope you can make sense of the drawings... One way I'll be saving space is to use the storage box tops for the lighting frame. This, along with the back screen, will help to create an enclosed space to minimise external light flooding the layout. I'm also planning to include the control panel within Baseboard 2. The current support structure for Tredethy Wharf has improved the stability at the expense of taking up more space in the car. My concern has been how to create a rigid support structure while reducing it's mass. I may have a solution in two trestles supporting and U girders, the proof being after it's constructed.

After dissecting the workings of the extraordinary 9ft. Pearson 4-2-4T engines in my previous four posts , I was interested to examine how these engines compared with William Dean’s later attempt to create something similar for the standard gauge. To make the comparison on as level a playing field as possible, I looked up information on the slightly later Pearson engines fitted with smaller 7’ 6” driving wheels – similar to those on Dean’s standard gauge engine. I have previously modelled the Dean engine, as described in my Pre-Grouping blog . Thee were eight of the original Pearson 4-2-4T design, with 9 ft. driving wheels, all built by Rothwell & Co. and delivered in 1853-4. There must have been difficulties arising from their novel features, as they were all rebuilt, with the usual form of inside frames and conventional springs, in 1868-70. In between these batches, two more 4-2-4T engines were built for the Bristol & Exeter Railway (B&ER) in Bristol. These were similar to the 9 ft. engines but with smaller driving wheels of 7’ 6” diameter. No. 29 was delivered in September, 1859 and No. 12 in April, 1862. These engines survived into GWR ownership and, as GWR No. 2005, the former No.12 remained in its original condition until broken up in about 1887. Ahrons, in “Locomotive and Train Working in the Latter Part of the Nineteenth Century”,Vol. Four, 1953, reports seeing No. 2005 frequently at Swindon and Bristol sheds. GWR No.2005 formerly B&ER No.12, built 1862 and broken up 1887 Taken together, these facts suggest that there may have been a closer relationship than has been recognised previously between Dean’s standard gauge 4-2-4T and the Pearson broad gauge 7’ 6”, GWR No.2005. Since I have already created a model of the Dean engine , I wanted to see how it compared with No.2005, by placing two models ‘side by side’. Creating a Model of B&ER No.12 (GWR No.2005) No.12 has been described as being similar to the earlier 9 ft. singles, although many of the ‘exotic’ features of the earlier engines had already been abandoned by then, even before the original engines were re-built. I found a fairly detailed description of the smaller engines, including an outline drawing, in ‘The Locomotive Magazine’, Vol . III. No. 36. Dec.1898 According to ‘The Locomotive Magazine’: “Their driving wheels were only 7ft. 6in. Diameter…. The diameter of the bogie wheels was 4ft, and the total wheel base was 25ft. 2in, the leading bogie having a base of 5ft. 6in., whilst that of the trailing bogie was 5ft. 9in., the driving wheels were 9ft. 4in. behind the leading bogie centre, and 10ft. 3in. in advance of the trailing. The boiler was 9ft. 9in. long, its maximum external diameter being 4ft. 2in., and the height of its centre line above the rail level 6ft. 11in.” This information was adequate for me to create a 3D model, which I based on my existing model of one of the 9 ft. engines. It was actually an easier modelling task, since these engines had conventional inside frames. Some peculiar featured remained, however, such as the water tank underneath the ashpan! Following my usual method, I created the boiler-smokebox-firebox assembly by reference to the above drawing, imported into ‘Fusion 360’ as a ‘canvas’. In addition to the driving wheels being smaller, the boiler was 1 ft. shorter than on the earlier engines. I used the ‘Move’ tool in ‘Fusion 360’ to modify faces of the original models of the 9 ft. engines, so as to match the profiles taken from the drawing. Creating 3D Boiler Assy with reference to Drawing I had to make new driving wheels, by my usual method, but re-used the bogie wheels and then assembled all the wheels around a new pair of full-length inside frames Creating 3D Chassis with reference to Drawing I took advantage of the way in which objects can pass through one another in the virtual world, by creating the two cylinders as complete ‘bodies’ that were then largely enclosed within the smokebox with parts of the sides protruding. The coke bunker only needed slight modification and the chimney and safety valve cover had to be re-profiled. One item which I have not modelled before was the curved handrail, which is such a prominent feature as it loops above the driving wheel splasher. This feature is easy to create in ‘Fusion 360’ by using the ‘Sweep’ tool. The path to be taken by the handrail is first created as a sketch, using the ‘arc’ and ‘line’ tools. Next the circular profile of the rail has to be created in a perpendicular plane. The ‘Sweep’ tool then causes the ‘profile’ to be extruded along the ‘path’, as illustrated below. Using the ‘Sweep’ tool to create a curved handrail in ‘Fusion 360’ So, it needed surprisingly little re-work before I had another model, representing the smaller-wheeled version of Pearson’s 4-2-4 tanks. My 3D model of Pearson’s 7’ 6” version of his 4-2-4T in GWR livery There’s a lot more detailing that could be added but I think this gives a good impression of the overall appearance of the real locomotive. Comparison with Dean’s standard-gauge version In parallel with developing this 3D model, I have also re-modelled the Dean standard gauge 4-2-4T in ‘Fusion 360’, so that I could place both versions together, to make some direct visual comparisons: I describe creating my 3D standard gauge model in in my Pre-Grouping blog. Pearson (broad gauge) and Dean (standard gauge) 4-2-4T Engines compared Looking at these two together, I think it is fairly obvious why the Dean engine had difficulty in staying on the track! With Dean’s inflexible bogie design and the excessive overall length, the lateral forces on any slight curvature must have been considerable, not helped by the large masses of water sloshing about in the long side tanks. It is possible that the two engines did actually come together at Swindon, since No.2005 was still around when No.9 was built and, according to Ahrons, a frequent visitor to Swindon. Dean 4-2-4T meets Pearson 4-2-4T Mike

Almost 10 years ago, I wrote a post about Dean’s experimental 4-2-4 tank engine , which made a brief appearance in 1882 before being hurriedly rebuilt as a more conventional 2-2-2 tender engine. Very little information has survived about the original engine, except that it had a chronic inability to stay on the track. With so little prototype information available – and even less that could be considered reliable – I felt justified in taking considerable liberties in the design of my model. The most glaring divergence from received opinion is my arrangement of the bogies, with the longer one at the back. I arrived at this decision after considering the layout of the rebuilt 2-2-2 version, which indicated that the outside Stephenson valve gear could not fit, if the longer bogie were at the front. I illustrate this point in the following diagram: Bogie arrangements compared to photo of Rebuilt No.9 Other aspects of my model that are entirely fanciful are the extended cab roof and the decorative ‘fake’ wheel arch. So the following photo is my own interpretation, which may or may not have some similarity to Dean’s prototype. My representation of Dean’s 4-2-4T at North Leigh Station More information about the construction of my model, which was built by traditional methods, using brass sheet, and was powered by a Tenshodo SPUD motor in the rear bogie, was given in my original post . Coming to more recent times, the extraordinary 4-2-4 tanks that were designed by Pearson for the Bristol and Exeter Railway have entered my sphere of interest. I have modelled these recently, as described in my Broad Gauge blog . One fact that has emerged is that two examples of a version of the Pearson engines, with smaller 7’ 6” diameter driving wheels, survived into GWR ownership, when they were numbered 2005 and 2006. GWR No. 2005, which was built at Bristol in 1862, remained in its original condition until broken up in about 1887. The point here is that this date is after Dean designed his standard gauge version! Furthermore, Ahrons, in “Locomotive and Train Working in the Latter Part of the Nineteenth Century”, vol.4, reports seeing number 2005 frequently at Swindon and Bristol shed. Taken together, these facts suggest that there may have been a closer relationship between Dean’s 4-2-4T and the Pearson 7’ 6” GWR No.2005 than has been recognised previously. In order to examine this relationship further, I decided to create 3D models of both No,2005 (broad gauge) and No.9 (standard gauge), so that I could place them side-by-side and consider the similarities and differences. In this blog, I shall describe my creation of a 3D model of No.9, while I shall tackle the other engine in my Broad Gauge blog. Creating a 3D Model of No.9 As I mentioned above, my existing model of No.9 was built by traditional methods, using brass sheet that I cut out by hand over paper templates. I still have the drawings, made using ‘Autosketch’ software, so I started by importing these drawings, as a ‘canvas’, into ‘Fusion 360’. I then followed my usual process of extruding the various components – boiler, firebox, frames, etc - from the drawings, to create 3D structures. I have previously described my methods in a blog post about creating a 3D model of a GWR ‘Sir Daniel’ class engine. For my current model, the initial layout of the components looked as shown below: Outlines of my Model Components over ‘Canvas’ in Fusion 360’ I added various details such as the outside Stephenson valve gear and the bogie side frames, to bring the 3D model up to a similar stage of detail as my brass model and then rendered the computer model in appropriate colours. After taking a screen shot of the 3D model, I added some more livery details in 'Photoshop' to give ‘character’ to the result. Remember that most of this comes from my own imagination, as we know very little about how the prototype was finished. I have tried to make it look like a ‘prestige’ express engine, which was apparently the original intention. My 3D model of No.9, rendered in ‘Fusion 360’ If the prototype really looked anything like this, I can understand why David Joy recorded in his diary, following a visit to Swindon in 1882 “I saw all about a mighty 'single' tank engine Dean and Charlton were building—8 ft-single and double 4 ft. - wheel bogies at each end. I saw drawings and all, and she looked a beauty. She was intended to do Paddington to Swindon in 2 min. under time," Comparison with Pearson Broad Gauge 4-2-4T I have described my 3D modelling of Pearson's engine in my Broad Gauge blog. Pearson (broad gauge) and Dean (standard gauge) 4-2-4T Engines compared Looking at these two together, I think it is fairly obvious why the Dean engine had difficulty in staying on the track! With Dean’s inflexible bogie design and the excessive overall length, the lateral forces on any slight curvature must have been considerable, not helped by the large masses of water sloshing about in the long side tanks. Dean was faced with several problems. He wanted to emulate the boiler capacity of Gooch’s 8 ft. ‘singles’, which would soon have to be replaced, so he had to increase the length to compensate for loss of width possible on a broad gauge engine. According to the RCTS booklet Part Two, “The domeless boiler was itself a. phenomenon, for it was one of the first in this country to be made in two rings and withal had a barrel length of 11ft. 6in.. not destined to be repeated for another ten years.”. The firebox also had to be lengthened, to maintain a grate area comparable with the wide firebox that was possible on the broad gauge. Another problem was how to accommodate large diameter cylinders, like those used on the broad gauge, together with their associated valves and steam chests within the narrower space between the frames. He tried placing the valves above the cylinder, operating them through rocking shafts from outside Stephenson valve gear. Most authorities agree that this engine was a complete disaster and must have been a considerable embarrassment to Dean - it’s not surprising that he didn’t want it talked about too much!. But he got over it and eventually came up with his own ‘singles’, which moved the valves below the cylinders in the ‘Stroudley’ arrangement and provided a much improved design of front bogie (after a pair of leading wheels proved insufficient) to keep the machine on the track. The long side tanks had to go and greater water capacity was obtained from a lengthened 6-wheel tender It is possible that the two engines did actually come together at Swindon, since No.2005 was still around and, according to Ahrons, a frequent visitor to Swindon. Dean 4-2-4T meets Pearson 4-2-4T Mike

I recently finished the ratio Toad kit. The whole thing was sprayed halfords white primer then humbrol 64 light grey. The solebar and below are revell matt black and handrails etc painted white. I wanted to have the van allocated to Croesnewydd although I have no photos of a BR era van with this legend. The areas for black were masked and sprayed. As @Mikkel suggested I used an HMRS sheet to construct the croesnewydd but only had the general wagon sheet so the Y was cut from HYBAR! I weathered with a black enamel was and sprayed the solebar and beneath with a mix of revell black and brown. Lamps and spratt and winkles to follow.

With the layout up, I have been able to assess and make a series of repairs required after its prolonged period in storage. First up was to fix and rectify all of the point mechanisms and prove the wiring such that I could get trains to run from one end to the other and back into the up and down yards. There's still a lit of errant ballast to deal with but I'm happy with progress. Most of the turnout droppers' soldered joints had failed and it took a while to sort out. I also fixed down some scenic sections which had come loose, reinforced the back of the layout where the road runs behind the hedge and dealt with the chasms which had formed at board joints, inserting new ply former pieces, applying filler and squeezing boards back together, with a sheet of cling film inserted to maintain the break. Scenics have been retrospectively applied and there's still a bit more to do.Photos show works in progress. The entire layout was then turned around so I could fix the fascia to the front. Filler has been liberally applied and it is currently primed, awaiting painting and scenery tweaks. This afternoon, I dragged the two 5ft fiddle yard turntables out of their hiding place and duly unwrapped them. These are Tim Horn products and came ready assembled. They're rather nice too. I couldn't resist putting some flexi track on the top to gauge how many roads I might be able to accommodate. At least 6 I reckon. They've been given a coat of Danish oil to seal the tops and I'll treat the underside in a similar manner. Once the fascia is done, the plan is to mate up the first and last board to their respective fiddle yard boards and finish the run off track work. Cheddar is going to the Railwells show in August as a work in progress, but I'd like to be able to run trains from one end to the other, if only to appease my sense of pride!

I ended Part Three with the prospect of modelling the many rods and brackets on the underside looming over me. I had intended to write more at that time but found myself struggling to understand how various parts of the engine fitted together. I think all the ‘easy’ bits have now been done, so I could no longer avoid the complex underpinnings. To gain an overview, I ‘mirrored’ one half of the split plan-view from ‘The Engineer’ and then colour-coded various elements – blue for frames, orange for crankshafts, green for valve gear, and red for wheel bearings. I made a couple of ‘corrections’ to the ‘mirror’ process by moving the cranks on one side to represent ‘quartering’. I have repeated this plan as a ‘header’ to this entry. following its use in Part Three . My 3D model overlaid on ‘The Engineer’ plan view I was pleased to find more information, which helped me interpret the various drawings, in an article from ‘Engineering’, 11th Feb.1870 (reproduced in the Broad Gauge Society (BGS) journal ‘Broadsheet’ No.27, Spring 1992). Although the article refers to the ‘rebuilds’, some of the information appears to apply to the original engines as well. I quote: “…. There is also a centre stay for the crank axle fitted with adjustable wedges; this stay is bolted to transverse plate in front of the firebox which ties the frames and assists in supporting the stay; The eccentric sheaves are of cast iron, as are also their respective straps, these latter having cast on the half that receives the rod two ears which with a pin inserted vertically and eye in the eccentric rod make a lateral joint. The valve gear is of that class known as Gooch‘s stationary link. ... The valve spindles are. guided by a cast-iron bracket bolted to the plates which carry the bogie pin and unite the boiler barrel with the smoke-box tube plate; these brackets have each a flat bar of iron or steel fitted for the spindle crossheads to slide on; these crossheads being similar to the piston crossheads. The reversing shaft is carried by two brackets bolted to the bottom slide bars.” Gooch ‘Stationary Link’ Valve gear I then found a lot more useful information in articles by Douglas S Johnson, published in two issues of ‘Broadsheet’, Nos. 83 and 84 (2020), in which he described constructing a model the ‘hard way’, using nickel silver and brass. While very helpful, these articles also provoked great sighs of relief that I was using 3D computer modelling, rather than facing the problems raised by real model engineering. Modelling the ‘Motion’ As before, I have tried to follow a ‘line of least resistance’, so decided that the moving parts of the motion were the easiest components to understand and place in their appropriate locations. My hope was that the locations of the various supporting brackets would become more obvious once I had the moving parts in place. One of the great things about 3D modelling in a computer is that individual parts will stay where they are placed, as though on ‘sky hooks’! Sketch of Motion over ‘The Engineer’ Drawing I started with the main drive-shafts between the cylinders and the driving wheel cranks. The rods are simply cylinders, produced by extruding their cross-section drawings. I have simplified the cross head by extruding from a plan view and then set in place two slide bars, above and below the cross head. I show these parts above the ‘canvas’ which provided me with the overall dimensions. My representation of the main drive components These parts will form a static representation of the motion – fully working motion would need metal bars and bearings, which are not on my agenda at present. Because of their prominent locations, they are needed for completing the external appearance of my model. Side view of the Motion in place on my model I followed up by using similar methods to create the various components of the valve gear. I made the profile of the Gooch stationary link by tracing over the above sketch of the valve gear and then created the various rods by simple extrusions from sketches. After creating the various components individually, I moved them into their appropriate locations on one side of the engine and then ‘mirrored’ the whole lot to the other side. My layout of Valve gear components Next, I put the components into the context of the rest of the model (minus boiler and smokebox), to help me to determine where the various supporting structures need to be placed. Setting the Motion in the context of my Model Before I could get much further, I needed to develop a better understanding of how this engine ‘worked’. Overall Engine Structure In most engines, the driving wheels transmit the force needed to pull the train, through a pair of strong plate frames running the full length on each side of the engine. These are linked at the back to a strong drag bar running across the width of the engine and carrying the couplings to following vehicles. In this Pearson engine, the strong plate frames are notably absent. The design has been likened to a road-going Traction Engine but, although there are similarities, they are not the same. In a Traction Engine, the driving wheels are near the back and transmit their forces through a strong frame at the rear end, which carries the necessary draw gear. The boiler in such an engine is a forward extension from the ‘pulling part’ of the engine, carried at its forward end by the steerable front wheels. A different analogy can be found in Brunel’s design for his Chepstow Bridge, in which he took advantage of the considerable strength of an iron tube to transmit both compression and tension forces. In Pearson’s engine, it is the boiler that provides this key structural component, being connected to the central driving axle through the yoke spanning the top of the boiler. As a tank engine, the design was intended to work in both directions. When running forwards the boiler transmitted the driving force in turn to the firebox, through a transverse frame member, and then to the rectangular tank underneath the coal bunker. The rear coupling hook was bolted directly to the back of this tank, which acted as a box girder. For running backwards the forces were carried by two plates riveted to the lower sides of the boiler, which transmitted the forces to the cylinder casting and then by a short shaft to the front coupling. I should point out that the above is my own interpretation after spending several days looking at drawings. If those with more engineering expertise see it differently then I shall be pleased to be corrected. This method of conveying the main driving forces through the boiler would not be permitted now. The fact that even substantial plate frames were subject to cracking under stress, suggests what could happen to a pressurised boiler in similar circumstances. Modelling the Structure It took a lot of head-scratching and poring over drawings before, largely by trial and error, I worked out how everything fitted together. The drawings show a plethora of riveted plates, which took me some time before I could understand their functions and how they fitted within the overall context of the engine as a working vehicle. I’m not sure that I can now recall all the steps that I made (and an account would be very tedious anyway) but the outcome of all my deliberations is shown below. I started with the basic rectangular frame, described Ahrons as “only 8in. deep for the greater part of its length except at the driving hornblocks. An arrangement of angle plates, 2ft. deep, was fastened to the side of the fire-box and to the front of the well tank. From this point to the back buffer beam there was no frame at all.” Next, I had to understand the curved plate that can be seen in ‘The Engineer’ side elevation, extending from the back of the smokebox and riveted along the lower sides of the boiler. I determined that there were actually two of these plates attached on either side of the casting that carries the front bogie mount. Their purpose was, apparently, to transfer tractive forces from the boiler to the front coupling on the engine. I placed them on my model as shown below: Modelling the Front-end Boiler Brackets I could now place the ‘motion’ I described earlier into the context of these brackets and the rectangular frame, as shown below: Setting the motion within the inside frame I could now work out the arrangements for the centre bearing of the crank axle and its fore and aft attachments to the firebox and front well tank. Centre-bearing for Crank Axle (outer bearings not shown) It all looks so simple now – it’s hard to take in how long it took me to figure all this out from the drawings I have 🙂 Actually, when I put it all together, perhaps it doesn’t look quite so simple! Quite a step up from my previous modelling methods: My model of the ‘Works’ It’s rather a pity that almost all of this becomes invisible once the boiler and outer frames are in place 😒 I also find myself wondering how the real engine was erected, with so many ‘inter-dependent’ parts. My 3D model in ‘photographic grey’ There’s not even much to see from underneath because it’s hidden by the well tank. My 3D model viewed from below After rendering in ‘Fusion 360’ my model looks like this: My 3D model rendered in ‘Fusion 360’ You’d have to look at this rather carefully to spot any visible differences from my earlier renderings! Now that I’ve teased out most of the internal features, which has been an ‘interesting’ mental exercise, I shall have to return to considering the ‘cosmetic’ appearance. There’s still a lot to be done on the details, such as rivets, boiler bands, and so on … and on. Oh, and brake gear on the rear bogie. Enough for now Mike

I’ve finally completed painting my pair of six wheel coaches which have been languishing on the work bench for far too long! Readers of this blog will know that coaches are definitely my nemesis, they always seem to take me forever to complete and these two have been no different! I’m taking Sherton to the York exhibition at the end of the month and that provided the enthusiasm to get them finished🙂 Diag V8 Passenger Brake Van Diag U14 Ist & 2nd Class composite carriage I like the variation in roof heights and styles which seem to typify a branch line train in the Edwardian era. Branch train comprising of 2021 class saddle tank number 2112, D14 brake 3rd, U14 1st & 2nd Composite, Diag C10 all 3rd and Diag V8 Passenger brake van They really shouldn’t have taken me 3 years to complete, but hopefully readers will think they were worth the wait!😁 I’m thoroughly looking forward to exhibiting at the York show, it’ll be the furthest North that Sherton has been, well and truly out of G.W.R. territory! Best wishes Dave

For some time, I have been feeling dissatisfied with the shaping of the frames on my model of the broad gauge engine ‘Rob Roy’ but couldn’t think of any ways to improve them, with the limited tools that I have. The construction of my model is described earlier in my blog. Recently I started to think about whether my 3D-printer might be able to help. I do like engines to be made of metal, so a complete plastic print wasn’t my favourite option, although I did find it a useful exercise for testing my modelling skills. I had the idea that it might be possible to make a tool or template, to help in forming brass sheet to the correct curved shapes. I couldn’t work from published drawings because I have modified the frames to suit some slightly over-size Tri-ang wheels, which I chose because they have the correct number of spokes for the GWR ‘Waverley’ class. These wheels are a very prominent feature of the prototype. My starting point was a JPEG image of the frames that I made for my model, which has some compromises in dimensions, to accommodate the wheels. It proved quite difficult to turn this into something that I could ‘extrude’ into a ‘solid’ model by using my 'Fusion 360' software. Rob Roy Frames (modified) – JPEG image Different software packages have their strengths and weaknesses. For this application, ‘Silhouette Studio’ has an excellent ‘trace’ function but has very limited export capability. My first step was, therefore, to open the JPEG image in ‘Studio’. One pitfall is that the image had be scaled to 72px/inch, which caught me out because I usually use 300 for printing. I was initially puzzled because the image appeared 4.2 times too big! Once I had a correctly-sized background image, I use the ‘trace tool’, with the various filters turned off. The result was an outline drawing, which I saved in ‘Studio3’ format. To get this drawing into ‘Fusion 360’, it needs to be converted to SVG, which proved tricky.There is, however, a website that will do an on-line conversion of ‘Studio’ files to SVG format, so, by using this, I now had the drawing in a format that I could insert into ‘Fusion 360’. In principle, the extrude tools in ‘Fusion 360’ can be used to transform an imported drawing into a solid object. In practice, however, my drawing turned out to have tiny gaps in the lines, which did not create the closed areas that are needed for extrusion to work. There is an ‘inspect’ tool, which identified a very large number of places where such gaps occurred but I don’t know of any easy way to close gaps in ‘Fusion 360’, other than on a point-by-point basis. Since the gaps are very tiny, it is difficult to find where to apply the editing tools such as ‘extend’ and ‘join’ and, in some places, they did not seem to work on the imported drawing. Failures seemed to occur where lines met some types of curves and would not connect . I needed another piece of software, to try and resolve the problem. So, I opened my SVG drawing in ‘Inkscape’ and explored the various ‘repair’ tools in that software. The ‘edit paths by nodes’ tool revealed that there was a very large number of nodes in the traced drawing. The ‘simplify’ command on the ‘path’ menu did a good job in reducing these to a more manageable number. By zooming in on the drawing to look at the detail of the nodes, it was easy to see where some nodes did not link up and it was easy to move node points so that they ‘fused’. I re-saved the drawing and inserted the new version into ‘Fusion 360’. Overall, the situation was now much better in that the main area could now be selected as a closed object. The ‘inspect’ tool revealed just a few problem areas and it was now feasible to give these points individual attention. In some cases, it was quicker simply to delete a short section and replace it with new lines. This method was sufficient to ‘close’ all the separate areas. It was only when I came to transfer the design to my slicing software, ‘Cura’, for printing that I realised that the scale had somehow changed during the transfer from ‘Inkscape’ to ‘Fusion 360’. In my previous work, I had always used DXF files from ‘Autosketch’ and these transferred correctly to scale. As a check, I tried saving the file in DXF format from ‘Inkscape’, which solved the scale problem, but the other problems of ‘loose ends’ appeared again and, in the end, I found it easier to re-scale the printer file within my ‘Cura’ software, before finally converting the model to ‘gcode’ for my E180 printer. The printed tool is shown below. For my purpose, the most important part is the curved top surface, which provides a firm base on which to construct my curved splashers. My first step was to glue a sheet of 10 thou (0.25 mm) brass sheet to one face of the tool. I used ‘UHU’ adhesive so that, after processing, the brass could easily be removed by immersion in hot water. I then used my Dremel ‘Moto-Saw’ to make a rough cut around the main features. This wasn’t as easy as I had hoped, since the saw operates with a vibrating motion and tended to pull at the thin brass sheet. It was, however, adequate for making a rough outline, which I could then refine by means of jewellers’ snips.. I found it easy to use the snips, now that the brass sheet was firmly attached to the tool, which I could hold comfortably during cutting. For the final trimming, to match the edges of the tool, I used a selection of needle files. Although the tool is, obviously, very soft, it was sufficiently firm to provide feedback when the brass edges had matched the tool surfaces. Once the frames had been shaped to my satisfaction, I started to add the curved top surface to form the splashers. For this, I used lengths of 5 thou (0.125 mm) brass shim. I used separate lengths for each section of the splashers, as I had done in my original model, but I feel it would be possible, with care, to fold the whole top as a single sheet. I provided a series of tabs along the back of the splashers that I folded down for attachment to the frame. Because the tool is plastic that melts easily, I could not solder these tabs in situ but, once everything was correctly shaped, I could remove the components from the tool, by immersion in hot water, and solder the parts together subsequently. I treated this as a ‘practice run’ and propose to try it ‘for real’ on some future engine builds that are in the pipeline. In fact, having looked at my ‘Rob Roy’ again, it doesn’t look nearly as bad as I thought and I shall finish it in its present form, while using the new techniques to build different designs. Having got this far, I decided to see how much extra work was needed to create a complete 3D-printed frame. The answer was not a great deal and, as a training exercise, I made a complete set of frames and splashers with ‘Fusion 360’, as shown below. It was necessary to extrude selected parts of the drawing by different amounts to create the 3D structure. I took the opportunity to add sand-boxes and rudimentary springs to my original drawing. One advantage of using computer-aided design is that producing a pair of right and left handed frames is simply a matter of pressing a ‘mirror’ button! So, here’s a pair of frames, straight from the 3D-printer, with Tri-ang driving wheels in place on one side. Although the splasher tops are rather ‘thick’, to allow successful printing, they are also surprisingly robust and this would be a feasible method to use … providing you are content with plastic engines. I intend to continue with brass construction but with the assistance of 3D-printed tools, to help in forming complex shapes. Mike