JohnBS

ASHBURTON AND TOTNES Locomotives 22 No 2568 0-6-0 ‘Dean Goods’ c.1930 A very attractive antique engine, based on the even earlier 'Armstrong Goods' Built 1898 Withdrawn 1953 The model is entirely scratch-built - this time in metal. Power is provided by a tender-mounted Portescap coreless 1018 motor with a small flywheel and a simple bent wire cardan shaft drive to a worm gear in the engine firebox. This feeds a double-reduction gear drive, giving an overall reduction of 50:1. Both engine and tender have split frames with driving wheels purpose-made by a member of the 2mm Scale Association and tender wheels from the Mike Bryant range. The above drawing shows the general arrangement in more detail than previously. (Note that the cardan shaft is drawn incorrectly - the loops in the wire should be both in the same plane.) The engine keeper plate, with profiles of the spring and hangers, was separate to permit the removal of the driving wheels for painting and servicing. I also drew out the profiles of the frames to finished sizes, shown in black (drawing otherwise is 4mm to 1ft). These were printed and stuck to the paired metal frame blanks to help in cutting out. Also, the drawing shows the detailed shape and key dimensions for the boiler fittings - a great help when turning. The engine and tender superstructures, details and fittings are of sheet and turned metal, as described previously. The combined weight of the engine and tender is 88g. More scratch-built tender locos still to come. John

ASHBURTON AND TOTNES Locomotives 21 No 4536 2-6-2T 45XX class ‘Small Prairie’ c.1925 The branch line pick-up goods engine. Built 1913 Withdrawn 1959 The model is entirely scratch-built in nickel-silver and brass with a split-frame chassis; again in the standard 2mm Scale Association methods. Power is provided by a Mashima can motor with a small copper-tungsten flywheel. A two-stage gear train gives a 37:1 reduction. Wheels are from the late Mike Bryant range, all are used for current collection including the pony trucks. These use the pivot for one polarity and a fine phosphor-bronze wire spring for the other. The drawing above shows general arrangement options considered for the 45xx class (top) and the 44xx class (bottom). The 45xx was selected - due to wheel availability ! The superstructure was of 20 or 30 thou brass with 10 thou nickel-silver shim overlays and fine wire for beading. The smokebox, boiler and boiler fittings were turned, Kadee couplings and other details were added. The model was airbrush painted, with Methfix transfers and etched number plates. The locomotive weighs 67g. More scratch-built models to come, John

Tim,Sorry, I got the wrong Myford number. John

ASHBURTON AND TOTNES Locomotives 20 No 1435 0-4-2T 517 class c.1922 A diminutive tank engine. Built 1877 Withdrawn 1932 This model was my first essay in scratch-building in metal – essential to achieve a reasonable adhesion weight in such a small engine. The chassis was of split frame construction, the standard 2mmSA method, with Mike Bryant wheels, so pick-up was from all wheels with no need for wipers. Power was provided by a Sagami motor in the cab and firebox with the worm in the boiler and a copper-tungsten flywheel in the bunker. A two-stage gear train gives a 65:1 reduction. The above drawing shows an early version of the general arrangement, with the flywheel then in front of the larger motor. To achieve the maximum adhesion weight, the boiler and smokebox, the side tanks and even the tool boxes were all made of copper-tungsten *, with every effort to get the centre of gravity within the driven wheelbase. The rear pony truck was pivoted on the centreline to ensure a rocking contact with the railheads. Nickel-silver coupling rods, wire handrails, turned boiler fittings and other details were then added and the model spray-painted, coaled and fitted with footplate crew. The locomotive weighs 61g. * Copper-tungsten has a Specific Gravity of about 18, depending on the alloy, and is up there with gold and uranium, compared to lead with a SG of 11. However, it is quite hard to find and very hard to work! The boiler and smokebox was made out of two lumps of the metal, epoxied together, clamped and then "cooked" in the oven. The sandwich was then fitted in the four-jaw chuck of Tim Watson's large Myford 7 lathe and turned to size - it almost caused the lathe to stall! This model won a Silver Medal at the Model Engineering Exhibition in 1985. More scratch-built locomotives to come. John

ASHBURTON AND TOTNES Locomotives 19 No 4820 0-4-2T 14XX class and Autocoach No 170 c.1935 The branch line autocoach passenger train. Built 1935 Withdrawn 1964 The model is a permanently-coupled engine and autocoach, the latter being the powered component. This is based on a Fleischmann diesel railcar with a new U-shaped chassis of 60thou black plastic card and the original motor and bogies. The drive mechanism is to one bogie, with the second only used for current collection. It includes a small flywheel and a two stage reduction gear with a lay shaft, giving an overall ratio of about 50:1 – great for slow running. The coach superstructure was scratch built - an inner layer of transparent plastic and 10thou white plastic card overlays. The roof was shaped from thicker plastic card and ventilators and rain strips fitted. The bogies have white metal sides and axle boxes; representations of the steps (used for platform-less halts) and front end details were added. The dummy engine has a scratch-built split frame chassis and Mike Bryant wheels, giving current collection from all wheels; current is transferred to the coach by permanent fine phosphor-bronze wires. The engine superstructure was based on Langley etchings with turned brass replacements for all the white metal components - smokebox/boiler/firebox, boiler fittings, etc. The engine and coach have a combined weight of 114g. The unit will easily haul a second trailer, when required for the school run. More scratch-built locos to come. John

ASHBURTON AND TOTNES Locomotives 18 Some more on King George II - an inside view after its trip to Swindon for a major overhaul. Having experienced the success of the re-motored Saint (about which more anon) I recently bought some more Nigel Lawton motors - 10x12s and 8x16s. It was clearly possible to fit a 10x12 in the King 4,000 gallon tender. I thought that I could fairly easily remove the original Farish motor and fit a simple worm housing to engage with the 32-tooth worm gear. This change was an attractive prospect as it didn’t entail any irreversible alteration to the chassis. If it didn’t work out, then at least I could put the original Farish motor back. This shows the new complete chassis. The motor fits comfortably in the coal space of the tender, with space for a copper-tungsten flywheel and a chunk of lead ballast in the rear. Once all was checked, the motor was fixed with a Sellotape "Sticky Fixer", (double-sided self-adhesive foam pad, about 1,5mm thick). Alternatively, the rear space (approx 15x11x9mm high) would be adequate for DCC decoder/Stay Alive capacitor/speaker. The original weight of the tender was 17g, this increased to 38g. The worm housing for the locomotive was a section of pivot steel passing through a length of brass tube soldered to a thick piece of nickel-silver. This in turn, was tapped and fixed through the chassis with a set screw and packing to adjust the meshing. Because the motor is coreless, there is no significant "cogging" and this means that the flywheel is very effective. Compared with the Castle, shown previously, the mechanism takes very little space, leaving lots of scope for additional ballast. In fact, I think that I will have a go at overhauling the Castle in a similar way. A top view of the locomotive. The drive shaft is a length of 0.31mm dia nickel-silver wire, bent to a loop at one end, which fits into a slotted sleeve in the flywheel. At the other end it is hooked through a section of tube soldered to the pivot steel from the worm. The new combined weight of the engine and tender is 135g. Some (largely) scratch-built locos to come. John

ASHBURTON AND TOTNES Locomotives 17 No 6005 “King George II” c.1930 The most powerful 4-6-0 Built 1927 Withdrawn 1962 The model started life as a Farish King with fairly severe changes. Again, the mechanism was adapted with a five-pole armature and a replacement worm and worm wheel set giving a 38:1 reduction instead of the original 25:1. Cosmetic frame layers with springing and brakes were epoxy-bonded to the chassis block and a new keeper plate was made from copper-clad fibreglass with phosphor bronze wire pickups. Driving wheels were salvaged from an old Fleischmann mechanism and are of near scale diameter. with scratch-built rods and cross heads. The working outside valve linkage operates as in the Castle. The bogie truck is scratch built, with the characteristic (dummy) outside bearings for the front axle. The motor pole pieces were thinned down, and enclosed in a new narrower fire-box wrapper of nickel silver shim, with the correct waisted shape, as for the Castle above. Again, the engine superstructure was modified to give clearance for the larger diameter wheels. New boiler fittings and cab details were fitted and bright steel details - tyres, driving wheel hubs, buffers, smokebox door hinges, front cylinder covers, reversing rod and handrails - were added. The tender chassis has current collection linked back to the loco and axle boxes, brake gear and other details were added. The tender superstructure was modified in detail with the coal space correctly represented. The combined weight of the loco and tender was 107g. A few more details later of the locomotive's visit to Swindon for a major overhaul! John

ASHBURTON AND TOTNES Locomotives 16 A bit more on "Caerphilly Castle" - the innards. This shows the whole loco and tender chassis, without the superstructure. The applied frames and brake rigging are just discernible, particularly at the front. This is a close-up of the thinned pole pieces and shows the increased clearance arc necessary for scale size driving wheels. Make sure that the cusps of the pole pieces still reach the chassis block. "Dartington Hall", described previously, was done in a similar way This is a close-up of the front section of the main chassis. Just visible on the right hand side is the chemically-blackened loop at the rear of the inside valve operating spindle. This engages in an extended piece of shim which forms the inside of the crosshead, thus moving the valve spindle backwards and forwards towards each end of the piston stroke. The spindle runs through the valve chest in the outside cylinder block and oscillates the valve linkage for the inside cylinders. When the locomotive is in motion, this movement is very satisfying. Let me know if you have any queries. John

ASHBURTON AND TOTNES Locomotives 15 No 4073 “Caerphilly Castle” c.1930 The first of the ‘Castles’. Built 1923 Withdrawn 1960 The model is substantially modified from a Farish Castle. A five-pole armature was fitted and the mechanism was adapted with a replacement worm and worm wheel set giving a 38:1 reduction instead of the original 25:1. Cosmetic frame layers with springs and brakes were epoxy-bonded to the chassis block and a new keeper plate was made from copper-clad fibreglass with phosphor-bronze wire pickups. Driving wheels were from the Beaver range, of near scale diameter and at scale centres, with scratch-built rods, cross-heads and slide bars. The working outside valve linkage was operated by a wire from the back of the cross-head in a blackened loop at the rear end of the valve piston. The bogie truck was scratch built with scale wheels. The motor pole pieces were thinned down, permitting a new fire-box wrapper of nickel-silver shim, with the correct waisted shape. (See notes on the construction of Dartington Hall in a previous post.) The engine superstructure was modified to give clearance for the larger diameter wheels by adding brass shims to the ground-out splashers, incidentally allowing for a representation of the polished brass beading. The skirt between boiler and footplate was drilled away and new turned metal boiler fittings and cab details were fitted. The tender chassis has current collection linked back to the loco and the tender superstructure was cut down and modified in detail to represent the earlier 3500 gallon type. Axle boxes, brake gear and other details were added. The combined weight of the loco and tender is a respectable 92g. Another modified proprietary loco yet to come. John

Jerry, A lovely edition (well, maybe I would say that !). Your editorial really hit the spot for me - life is too short to create a couple of exhibition layouts and the necessary rolling stock without compromises. What those compromises are is up to the individual modeller. With the wisdom of hindsight, things may have been done differently, but hey-ho. Best wishes, John

ASHBURTON AND TOTNES Locomotives 14 No 4083 “Abbotsbury Castle” c.1935 One of the second batch of 'Castles' Built 1925 Withdrawn 1961 This model was my first attempt at "heavy" modification of a proprietary loco, many, many years ago. However it turned out to be a fairly simple reworking of the old Peco Jubilee – remarkably similar in key dimensions to the Castle. Well, Stanier was trained at Swindon! The model engine and tender chassis and mechanism were unchanged, except for "borrowed" Farish cylinders and new scratch-built connecting rods, cross-heads and slide bars. The Peco bogie truck was modified with ore presentation of the outside bolsters. The engine superstructure has a slightly raised firebox top in plastic card and a new scratch-built cab to conform to Swindon practice. The front end was modified to show the inside cylinders and curved steam pipes of heavy-gauge electrical cable. New wire handrails and other fittings and details were added. The tender frames were butchered slightly and the superstructure was scratch-built in plastic card with a very substantial coal load, necessary to cover the vertically-mounted motor. The combined weight of the loco and tender is 120g. More modified proprietary tender engines to follow. John

ASHBURTON AND TOTNES Locomotives 13 No 4918 “Dartington Hall” c.1930 The Hall was the GWR all-purpose main line engine. Built 1929 Withdrawn 1963 The model started life as an ancient Farish Hall – with severe modifications. The mechanism was adapted with a replacement worm and worm wheel set, giving a 38:1 reduction instead of the original 25:1. The three-pole armature was replaced with a five-pole and the pole pieces were ground down to allow for the scale diameter driving wheels and thinned to fit within a waisted firebox. * The model's original firebox walls were reduced in thickness, particularly below the centreline of the boiler, and then a wrapper of nickel-silver shim was epoxied to the ground-down firebox and fettled to shape. Cosmetic frames with springs and brakes were bonded to the chassis block and a new keeper plate was made from copper-clad fibreglass with phosphor-bronze wire pickups. Driving wheels were from the Beaver range with scratch-built nickel-silver crossheads and connecting and coupling rods. The pony truck was a modified Peco Jubilee unit and the cab was scratch built in metal. Turned metal boiler fittings, wire handrails and other details were added. The tender was an unmodified Farish 4000 gallon type but with current collection and springs, axleboxes and other details were added. The combined weight of the loco and tender is 96g. * This pre-dates the availability of small replacement motors (Nigel Lawton 8mm, etc). Be careful if you are trying this at home - first you need to remove the magnet, then push out the aluminium rivets that hold the pole pieces (or, on some versions, pull the pole pieces off the moulded studs). When working on the pole pieces, take care to avoid reducing the cusps - these need to bear on the chassis block to stop the pole pieces swinging in to collide with the rotor. Fit the new armature - a straight swap - and re-assemble. Make sure that the magnet goes back the right way round or the motor will run backwards! More modified proprietary tender engines still to come. John

ASHBURTON AND TOTNES Locomotives 12 No 3265 "Tre Pol and Pen" (Earl class) 4-4-0 c.1935 An interesting rebuild of Bulldog frames with a smaller boiler, popularly known as a Dukedog. Built 1930 Withdrawn 1964 The model was a first try with a Union Mills engine. These have a tender drive, with traction tyres, and "American" style pick-up (loco from one rail, tender from the other). As I wanted to replace the moulded handrails and some other details, the nicely-cast white metal superstructure was stripped of paint and the unwanted mouldings were filed and scraped off. Then I modified the superstructure by deepening the axle and crank recesses and reducing the frame depths to lower the footplate height to a more prototypical appearance. (Be careful if you try this; you may need to reduce the flanges and/or grind out some of the underside of the footplate as tolerances are fairly tight.) At the same time, I reduced the overall width of the loco by about 1.2mm. This was achieved by widening the upper part of the frame slots which allowed the crank webs to be pushed in slightly and the axle lengths correspondingly reduced. The latter are fairly hard steel and need to be shortened with a grinder or cutting disc - be careful in doing this as the plastic cranks can easily melt ! As Union Mills now use a smaller motor, I managed to squeeze a little more lead in the tender. Then it was time to add some details - dummy front coupling, wire handrails, smoke box dart, lamp irons, brass whistles, brake rigging and a new rear coupling. Then all was repainted and weathered, lamps fitted, coaled and a crew added. Finally, number- and name-plates were ordered and have now been added. The combined weight of the loco and tender is a hefty 147g. More modified tender engines to come. John

Angus,Later in this thread I can republish an article that I wrote many years ago which details simple 2mm scale chassis building and how I built the superstructure of a loco in plastic card. Would this be a good idea ? John

ASHBURTON AND TOTNES Locomotives 11 Another tender locomotive. These powerful locomotives were the mainstay of GWR long distance heavy freight engines - they could haul up to 100 wagons. No 2857 2-8-0 28XX class c.1930 The archetypal coal and mineral main-line engine Built 1918 Withdrawn 1963 This model started life as a scratch-built superstructure on a cut-down Minitrix 9F chassis (the fifth axle being removed), re-motored with a small Minitrix motor in the boiler. Perhaps inevitably, the motor was inadequate and fairly soon gave up the ghost. However it seemed a possibility to use a Farish 8F chassis so I gave it a try. The old three-pole armature was replaced with a five-pole one. The motor pole pieces had to be thinned down to allow a waisted Belpaire fire-box shape and the chassis idler gear was modified to give a two-stage reduction of about 42:1 - only possible with the older brass gears. As usual, new scratch-built cross-heads and connecting rods were made of nickel-silver with slide bar brackets of T-section brass. The plastic card superstructure was made as described previously, with wire handrails, metal boiler fittings and plenty of lead in the smokebox and boiler. The tender used a modified Farish chassis, with current collection and with a 3500 gallon type superstructure of plastic card with metal details and fittings. The combined weight of the engine and tender is 89g. More modified proprietary tender engines to come. John

ASHBURTON AND TOTNES Locomotives 10 No 9304 2-6-0 ‘Mogul’ c.1935 An intermediate mixed-traffic engine. Built 1932 Withdrawn 1963 This engine was my first essay in scratch-building of locomotive superstructures in plastic card - or in anything! At the time, I felt more confident in using plastic than metal - I had become used to the techniques and it is much easier to cut and join. As the previous loco, the chassis of the model started life as a Farish large prairie tank engine, with the rear end cut off and married to a Farish tender. The mechanism was unchanged with a reduction of 25:1 but the engine was re-wheeled with Beaver wheels and fitted with new scratch-built coupling and connecting rods, a new keeper plate and a pony truck. The tender is on a spare Farish chassis, with superstructure modified to a 3500 gallon type, and with current collection (phosphor-bronze wire wipers), connected back to the loco. The locomotive superstructure is scratch-built in plastic card as described in previous entries, with metal details and fittings. The model has just been refurbished and is still going strong. The loco and tender have a combined weight of 70g. More modified proprietary tender engines to come. John

Tim,Thanks for that. Ordered a set yesterday afternoon and they arrived midday today. They look like the dog"s bxxxxxx and the case is great. Charged up the li-ion battery this afternoon and all seems to work fine, particularly like the concentrated light. I am still adjusting the width settings as I am having problems with double vision (sober as a judge) but I’m sure I’ll get used to them. All in all, a good bit of kit - these days, I need all the help that I can get. Best wishes, John

ASHBURTON AND TOTNES Locomotives 9 No 5185 2-6-2T ‘Large Prairie’ c.1935 A local passenger and mixed traffic engine. Built 1931 Withdrawn 1960 The model began life as a Farish large prairie, The chassis and mechanism were largely unchanged with a single-stage reduction of 25:1. However, that's where the proprietary model stops - I wasn’t particularly happy with the appearance of the model so I thought that I would try to improve things. The engine was re-wheeled with Beaver wheels, scratch-built connecting and coupling rods, crossheads and slide bar supports. Then a new keeper plate with phosphor-bronze pickups and new split-frame pony trucks, electrical connected to the keeper plate, were made. The entire superstructure was scratch-built in plastic card. Again, the smokebox and boiler was formed as a ”swiss roll” of two layers of 10thou, around 30thou former discs. The structures of the footplate, tanks, firebox, cab and bunker are again of 30thou with 10thou overlays and with fine plastic rodding as beading. Details such as splashers, steps, tank fillers and chimney were generally of plastic with metal handrails, whistles and other small fittings. The smokebox, front of boiler, bunker and tanks were filled with lead. As usual, painting was by airbrush (green) and paint brush (the rest) with Methfix transfers and etched number plates. The loco weighs 55g. Next time, we will move on to modified proprietary tender engines. John

Steve, Thanks for your kind comments. I’d love to see if we can meet-up somewhere - PM me and we'll see if we can arrange something. Best wishes, John

ASHBURTON AND TOTNES Locomotives 8 No 8731 0-6-0T ‘Pannier Tank’ c.1935 Maid of all work. Built 1931 Withdrawn 1962 This model is in essentials a Farish pannier with lots of minor modifications, as described by that excellent modeller John Greenwood in a copy of the Model Railway Journal. The mechanism has a replacement worm and worm wheel set, giving an improved reduction ratio of 21:1 instead of the original 16:1. A new keeper plate was made from copper clad fibreglass, with phosphor-bronze wire pickups. Brake gear, sand boxes and guard irons were fitted. The solid skirt beneath the tanks was cut away and a new lower section of the boiler, made from a suitable sized felt pen barrel and fixed to the chassis, covers the gear drive. A new brass safety valve casing brightens things up and the chimney is raised to scale height by the simple expedient of adding a suitable metal washer under the capuchon. The coupling rods were thinned and sanding gear rodding, separate wire handrails and various bits of pipework finished the model off. The model weighs 55g. Yet more modified proprietary tank engines to follow. John

ASHBURTON AND TOTNES Locomotives 7 No 1506 0-6-0T ‘Saddle Tank’ c.1922 An antique tank engine. Built 1878 Withdrawn 1937 Buried under this model is a Farish pannier (the reverse of reality - Great Western converted many saddle tanks to panniers). The mechanism has a replacement worm and worm wheel set, giving an improved reduction ratio of 21:1 instead of the original 16:1. A new keeper plate was made from copper clad fibreglass with phosphor-bronze wire pickups. Wheels were unchanged, brake gear, sand boxes and guard irons were fitted and the coupling rods were thinned down as far as I dared. After separating the superstructure, the cab and bunker were removed and discarded and all the boiler fittings were filed off to leave a flat top. To this, a nice fat piece of nickel silver was epoxied and cured in the oven. Then the whole lump was ground and filed down to the correct profile, checked with a simple metal gauge sliding along the footplate. The footplate itself was shortened at the front and new metal handrails, smokebox and boiler fittings were added. The back of the Farish motor, where it projected into the cab, was pared down to the minimum and footplate crew were positioned judiciously. The old-style open cab and bunker were formed of sheet metal. The loco weighs a respectable 54g. More modified proprietary tank engines to come. John

ASHBURTON AND TOTNES Locomotives 6 Another modified proprietary tank engine No 5505 2-6-2T 4575 class ‘Small Prairie’ c.1935 The Totnes station pilot. Built 1927 Withdrawn 1957 This started life as a Fleischmann model of a German tank engine and retains the core of its mechanism - motor, gears and wheels. The motor is a fairly chunky open-frame type, driving all axles through a double reduction gear train. The cylinders and slide bars are filed down ex Farish (nice and robust) with scratch-built connecting and jointed coupling rods, cross-heads and brass T-section slide bar brackets. New split-frame pony trucks have been made, the front picking up from the right hand rail and the rear from the left. All in all, it runs very sweetly, though it is a bit speedy. The superstructure is scratch-built in plastic card. The smokebox and boiler is formed as a ”swiss roll” of two layers of 10thou, around 30thou former discs. The structures of the footplate, tanks, firebox, cab and bunker are again of 30thou with 10thou overlays and with fine plastic rodding as beading. Details such as splashers, steps, tank fillers and chimney are generally of plastic with metal handrails, safety valve casing, whistles and other small fittings. The smokebox, front of boiler, bunker and tanks are filled with lead. The loco weighs 46g. More modified proprietary tank engines to come. John

Hi Bill, Agreed, a bastard type of English Garden Wall bond. John (retired architect)

Hi CarriageShed, A nice idea, however a few thoughts: First, weight. 4-4-0s are notoriously difficult to achieve adequate traction weight and this would be exacerbated with a light weight 3D printed superstructure. If using a Farish chassis, the only space for a slug of lead is in the front of the boiler and smokebox but this is exactly where you don’t need it. The centre of gravity of the loco must be within the driving wheelbase. Secondly, the old Poole Farish motor needs quite a bit of butchery to the pole pieces for it to fit in the round-topped boiler and firebox - a high risk exercise. I had originally hoped to make a T9 "Greyhound" but soon realised that the narrowness of the boiler/firebox made that impossible. Thirdly, although not essential, the model benefits from having replacement larger diameter driving and bogie wheels and these are not easy to find. I guess that another approach would be to look at doing something with the Dapol Schools chassis. Best wishes, John