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52 Class assembly OO Gauge.

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I updated the artwork for the model on completion of the assembly of the test etch and was finally able to schedule time to start assembling the updated version of the model.

The original test build was based on No1 in early GSWR/early GSR condition with 3 ring boiler with raised firebox and short "sports" cab, this build is based on a photo of No 98 in early CIE condition with a 2 ring boiler with raised firebox and longer J15 style cab and side sheets.


The parts are etched in 0.4mm nickel silver for it greater strength and rigidity than brass. The metal is also easier to work with than brass and provides a superior key for paint.

Basic tools include a tapered broach for opening out the axle holes for bearing brushes, needles files, the rivet press is not an essential for this build!


Loco, bogie and tender frames laid out and bearing brushes soldered in place.


Bogie awaiting assembly, the tabs on the center section of the bogie (bolster) fit into the slots in the bogie sideframes, the complete assembly self aligns when assembled on a flat surface. I used a toolmakers clamp to keep everything square when soldering the bogie sideframes to the bolster.


Completed bogie assembly with cosmetic sideframes soldered in place. I thinned the back of the cosmetic frames with 145°  solder and sweated the cosmetic frames to the bogie using a small stainless steel clamp.


Jumping ahead a bit! Main frames and bogie. The clamp is to keep the mainframes from tipping forward.

I aligned the loco main frames by first soldering the framespacer that fits above the driving axle in place, then checking/adjusting the chassis that everything was flat before soldering the rear frame spacer in place.  In the absence of a clear datum I used the guard irons and springs to check that the chassis was sitting on a flat surface.


Chassis with leading frame spacer and motion bracket slotted in place.

These can be soldered in place at this stage if the loco is assembled without inside valve gear!

I hope to cover the assembly of the valve gear separately.


Bogie pivot and motion bracket tapped 10BA for bogie pivot bolts, bolts then soldered in place.


Frames with motion bracket and bogie pivot plate soldered in place.


Bogie and frames united.


Ashpan and power pick up mounting plate. 


Chassis with ashpan sides and pick-up plates fitted. The ashpan sides and frames are aligned using pieces of 0.45 wire that fit through pre-formed holes.

I will cover the remainder of the chassis assembly in another post.


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Pressing on with the loco and tender chassis assembly.


Underside of loco chassis showing pick up plate & 0.7mm brake hanger supports.


Tender chassis, with U shaped spacers for aligning brake hangers and shoes.

Chassis is designed on the same principals as the loco chassis with the frame spacers slotting into tabs in the frames, the kit is supplied with frame spacers suitable for OO and 21mm gauge.


Photos look clearer on a white background. 

The tender chassis is based on the weighted tender principal with the drawbar transferring weight to the loco and the leading and center axle lightly sprung to stay on the track. Springs are 0.4mm phosphor bronze wire.


Assembled loco and tender chassis. I will fit the brake gear after I have fitted the wheels and test run the loco.


Loco chassis, surplus solder to be cleaned up.


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Body assembly running board and cab. The Beyer Peacock style running board with its curves multiple levels and shallow valence is probably the most challenging aspect of building a model of a 19th Century GSWR passenger. 

Drew Donaldson apparently got over this problem by forming the valences from rail or square section metal over a former.

In the kit the valences form part of jig which supports the valences and running board during assembly.


Body fret: The etch was prepared in June but I did not have time to tackle the assembly until this week.


Running board parts including valences and running board.


Running board assembly jig folded up, this is based on a concept used by Terry McDermott in the TMD J15 kit in 1985.


The rear of the running board together with cab steps and drag beam is formed separately from the main part of the running board as its not practicable to form the running board from a single piece of brass due to the multiple level nature of the running board.


Bending the drag beam to shape, the visible outer section of the beam folds outwards at 180° rather than conventionally on the inside of the fold line.


Completed drag-beam and step assembly


I used a piece of mdf and card to pack the running board to the correct height with the top of the running board level with the top of the valences.


I used s/s clamps to secure the running board in place while soldering the flat front section of the running board to the valence one edge at a time.

I used a higher temperature (180°) solder for this stage of the assembly to minimise the risk of joints failing during the more detailed stage of the assembly (overlays, cabs splashers) with 145° solder.


The leading flat section of the running board is now soldered to the valences/jig. The holes at the rear of the running board and drag beam are tapped 10BA before bolting the drag beam in place.


Drag beam now bolted in place the running boarded can be soldered to the drag beam and remainder of the running board soldered to the valences.


Running board overlays, these are fitted by thinning the underside of the overlay and top surface of the running board with 145° solder and sweating with an iron with a clean tip working from the front edge of the running board and working backwards. There are etched lamp iron holes in both the overlay and running board to assist alignment. 

I again used s/s clamps to hold the flat front section of the overlay in place while soldering and used a soldering tool to dress the overlay to the curved section of the valence while soldering in place. https://nz.rs-online.com/web/p/soldering-accessories/2266331/


Overlays soldered to the running board and valences.



I next soldered the cab to the running board to provide some rigidity to the weakest section of the assembly.

The cab sides are designed so that the loco can be assembled in either GSWR condition with a short roofed cab and little or no visible riveting or CIE version with longer cab roof and side-sheets and visible riveting. I impressed the rivet detail using a rivet press.


Starting to look like a loco, the cab sides locate into slots in the running board which helps keep everything square.


I again use a soldering clamp while soldering splasher sides in place.



I removed the jig once the cab was soldered in place and fitted to the chassis to check that everything was sitting level.


With the jig removed I checked that the soldering of the joints between the overlays/valences and running boards was adequate reinforcing the joint between the valences and running board where necessary particularly around the curved sections of the running board IMG_5625.JPG.253307feaa08f326e5e01b851a0be638.JPG.

The assembly threw up one or two glitches which are easier to rectify at this stage.


Edited by Mayner
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  • 4 weeks later...

I didn't have time to do anything on the modelling front during the past three weeks, but made some time to do some work on the 52 Class this afternoon.

The kit is based on a locomotive with a raised round topped firebox, which adds a number of challenges to both the design and assembly. 


The boiler and firebox is designed as a sub assembly, with a bayonet fitting of the firebox into the cab and a bolt fixing to the smokebox, so that the whole sub assembly can be removed for painting. The firebox and boiler sections are joined by a cast brass step ring. The step ring was cast from a 3D printed pattern.


I used a tool makers clamps to secure the step ring to the firebox during soldering.


I used phosphoric flux (home mix) 145° solder and soldering iron (55watt)with a chisel tip to solder the casting and sheet parts together.



One of the challenges of building Victorian locos with large wheels and small low pitched boilers in OO! 


I basically offered up the boiler and firebox to the running board checked that everything was level then scribed the splasher outline on the boiler wrapper and cut away the metal that would foul on the driving wheels using a fine toothed piercing saw.


I soldered the step ring to the boiler once I cut away the surplus metal from the wrapper, I again used a toolmakers clamp to align and secure the boiler to the firebox while Soldering, the step between the boiler and firebox is approx .5mm and used a piece of metal cut from the boiler wrapper as a packing shim during soldering.



While the cut outs in the boiler worked reasonably well I need to remove more metal from the firebox wrapper to achieve sufficient running clearance for the wheels.



Thankfully the large cut outs in the boiler are not really noticeable of the partially assembled model thanks to the combination of large splashers and low pitched boiler.

The circumference of the boiler wrapper and diameter of the boiler front former needs to be increased to eliminate the gap between the two sections. 

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  • 4 weeks later...

The smokebox design is fairly typical of etched kits with a half etched wrapper with rivet detail that fits around a fold up former. 


The former is designed to fold up from a single piece of nickel silver with a spacer to keep everything square, in this case I managed to solder the spacer at an angle, but the overall assembly is square and vertical.


Test fit of smokebox former to check that boiler is sitting level before fitting the wrapper.


Paper to protect the wrapper in the rolls.



Soldering the wrapper in place, the GSWR waisted smokebox wrappers are challenging to form, I checked that the bottom edges of the wrapper were even the same distance from the bottom of the wrapper, before tack soldering the wrapper to the former at the top of the smokebox the re-checking before soldering the wrapper to the top half of the former, then repeating on the other side.


I then dressed the skirted section of the wrapper to the former, using suitably sized dowel/aluminium rod as a former then soldering in place.


Smokebox front waiting to be soldered in place.


I thinned the front of the smokebox former then sweated the front of the wrapper in place, working along the bottom edge of the overlay and the rebate for the smokebox door, this reduces the risk of getting solder on the riveted detail. I use a similar approach soldering the wrapper to the former.


Completed smokebox assembly bolted to the boiler, everything sitting level.


Starting to look like a loco?

Major assembly complete interior and backhead to be fitted

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I cheated a bit and fitted handrails and ejector pipework since the last installment. Handrails and pipework are a mixture of 0.45 & 0.9mm straight brass wire from Alan Gibson and short and medium handrail knobs & fine copper wire from the same manufacturer.


I drilled out the holes for the cab handrails using an 0.5mm drill and a pin chuck and opened up the holes for the handrail knobs using a taper broach, checking for size with a handrail knob held in a pin vice/chuck, the ejector pipe is held in place with split pins formed from soft copper wire, threaded through the holes in the boiler wrapper and ten soldered in place.

I used a piece of thick card as a spacer between the handrails and cab side securing in place with a small stainless steel clamp while soldering the handrail in place form inside the cab.


Allowing for OO and 21mm gauge is the biggest challenge in designing the cab interior for an Irish loco. I decided to design a single cab interior that could be assembled in either gauge rather than the two separate fold up interiors incorporated in the design of the MGWR 2-4-0.

Splasher/seat assembly, the half etched line in the splasher top/end is for the 21mm version.


OO splashers sub-assemblies


I am not happy with the excessive width of the OO splashers and will revise this aspect of the design in the production version.


Splashers reduced in thickness, with cab floor slotted to fit between loco main frames still not 100%

With the loco detailing substantially complete its time to detail the SSM tender.


98s tender is "borrowed" from an SSM J15 kit detailed with a combination of SSM and my own detail castings


I decided to mount the springs on 0.45mm brass wire so that the springs can be fitted in place after painting the tender.

I drilled the backs of the springs 0.5mm before soldering the pins in place with 100° solder.




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First day of 2021 a good opportunity to crack on with the assembly and fitting of the brake gear and coupling rods.

I usually design and assemble the brake gear as a separate sub-assembly that can be removed from the chassis for painting and maintenance, the 52 Class added a few additional challenges due to the brake hanger design which is similar to other late 19th GSWR passenger tender and tank locomotives.


Each brake hanger and shoe assembly is made up from 3 separate pieces.

First step is to drill out the pivot holes 0.8mm and the holes for the brake shoes 0.5mm before removing from the fret using my trusty pin chuck 


I haven't been able to achieve a clear close up photo of the drilling operation.


I made up a simple assembly jig for the brake hangers using a piece of hardwood and short pieces of 0.7 & 0.45 mm brass wire.

The first stage of the assembly is to fold over at 180° the "washers" at the top and bottom of the hanger with the half etched brake shoe. 

The holes in the top of the hanger are circular and intended to be a push fit onto the 0.7mm pivot pins on the chassis, the holes on the bottom of the hanger are square and are designed to fit onto the shouldered ends of the brake stretcher bars.

The 0.7mm pin on the left is used to locate and align the pivot point of the hanger, the other pins serve to locate the brake shoe and bottom of the hanger.



Stage 2 brake shoe separated from the hanger.


Stage 3 the shoe is soldered to both parts of the hanger and the 0.45mm pin. I then removed the pin from the bottom of the hanger before soldering the two sections of the hanger together and then repeating the process for the top pivot point.


Brake hanger assemblies awaiting cleaning up. I cleared the top pivot point with an a small tapered broach and an 0.7mm drill and trimmed the pin flush with the sides of the brake hanger.


Brake hangers fitted to the loco stretcher-bars and pullrods awaiting assembly.

The stretcher bars are shouldered to align the pullrods and brake hangers in the correct position for in this case OO gauge.


I first soldered on end of a pull-rod to a stretcher bar making sure that they were at right angles before soldering the other three joints. 

The rearmost section of the pull rods are formed to shape once the stretcher bars are soldered to the hangers.



The photo is of a 21mm chassis but the same principal applies in OO


OO Chassis with brake gear and coupling rods fitted!


Coupling rods are laminated in two layers from nickel silver




I clamp the rods in a  pin vice while soldering the two sections together working along the edge with a soldering iron with a fine tip.


Most critical stage of the assembly gradually increasing the size of the holes with a combination of drills and tapered broaches to achieve a clearance fit on the crank pin bushes.

This loco is fitted with Markits wheels with their slotted crankpin system which incorporates a slotted securing bush.


Almost finished job, tender brake gear and filler cap to be fitted, motor gearbox and power pick ups and couplings before testing and painting.


One of the surprising things about designing the model was the small size of the 52 Class for an express passenger loco even compared to the Midland Ks/GSR 650 class not exactly a large loco.

Introduced in 1883 the 52 Class were displaced from the Cork expresses by the slightly larger 60 Class during the mid 1880s, curiously Inchacore continued to build both Classes up to 1890.


No 1 & No 59

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Beginning to draw the saga to a conclusion with assembling the tender brake gear, assembling the mechanism and final detailing before hooking the engine up to the tender.

The tender brake gear was assembled as a removable sub-assembly, similar to the loco but a lot more fiddly.


First step was to drilled out the pin holes using 0.5mm and 0.8mm drills in a pin chuck.

The 0.8 holes are for attaching the hangers to the pivot points on the chassis.


Brake shoes soldered to the hangers.


First stage in assembling the brake gear solder one pull rod to an 0.45mm brass stretcher bar.

The idea was to thread the four of the brake shoes and the remaining pull rods onto the stretcher bars before fixing in place on the chassis in a similar manner to the loco.


The original idea was to solder the outer pullrods in place before soldering the inner pullrods and brake hangers in place, with card spacers to keep the outer rods clear of the wheels.

In practice it would have been simpler to solder the pullrods to the stretcher bars on a jig on the bench then solder the hangers in place once fitted to the chassis, the center pullrod and hangers were threaded in place once the assembly was fitted to the chassis.



GSWR 1864 gal tender chassis with distinctive double brake pull-rod arrangement.

The wheels are temporary Hornby coach wheels as I am out of stock of Markits tender wheels.

The outer pull rods need to be realigned so that they are parallel to the inner pair before the chassis is painted.


Final? stage of tender detailing brake shaft and linkage. I still need to manufacture a pattern for the tank filler  and cap.



Motor is a 10X20 coreless type supplied by High Level Kits, gearbox is a High Level Road Runner + set up in an L configuration.


This arrangement keeps the motor and drive largely clear of the cab with the motor set low in the boiler/firebox.


Loco is wired for DC with the "American" pick up system with the motor bonded to the loco frames and a flexible connecting to the tender.



Final loco and tender components. 

Drawbar formed from a piece of copper clad sleepering.

Brake shaft and pipework.


Nearly complete and test run drivers side No98, toolboxes, vacuum pipes and couplings to be fitted cab interior, tender tank filler and ballasting/balancing to be finalised.

Running is quite smooth and fast!, but I have to trace and sort out some intermittent shorts between wheels brake riggings and bogie frames.



Firemans side.


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98 had her first successful test run including continuous running on an oval with Hornby No3 curves.

The main challenge is balancing the loco and getting enough weight on the driving wheels, she is quite nose heavy even with a weighted tender.

Definitely built for speed!



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  • 4 weeks later...

No 98 on test.

I set up a OO gauge test track in a corner of the garage using Hornby No 3 curved & straight track on some offcuts of ply to test 98s haulage capabilities starting with 12 MIR hoppers. 

The hesitation at one point of the run seems to be a misaligned rail joiner.

High Speed Test Run!

Turned out to be a bit too much for one of the wagons!


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  • 3 weeks later...

98 final assembly back from the paint shops.


Sub assemblies and tools.

Before painting the loco was washed to remove any remaining traces of flux, verdigris and other crud before sand blasting with aluminium oxide with a Badger Air Abrasive Gun. The wheels were de-greased with Isopropyl alcohol before I masked the wheel threads, tyres and axles with Tamiya masking tape.

The loco was primed with a Finixa aerosol etched primer, the initial coat allowed to cure before applying a second which acted as a surfacing coat. 

The loco was painted with an aerosol lacquer matched to a sample of GSR grey. The painted model was left to cure for approx a week before attempting assembly.


First job was to clean out the axle bearing holes and fit the driving wheels. I usually use Markits wheels in OO they have stainless steel or nickel tyres, diecast centers and fit on squared axles which self quarter. I use the "live axle" system on OO gauge tender locos picking up the power through the loco driving wheels on one side and returning through the tender frames and wheels on the opposite this simplifies assembly and is extremely reliable. Checking that the live wheels are on one side I fixed the wheels to the axles using the Romford/Markits slotted axle/crankpin nut and screwdriver system, I first check that the wheels are seated properly on the axle before using thread lock to secure the axle nuts in place. I have had Romford wheels and crankpins work loose in the past, not a great experience.

When I assembled the loco for test running I screwed but did not thread lock or loctite the crankpins in place. The crankpins unscrewed from the wheel centres when I attempted to remove the crankpin bushes while dismantling the loco for painting!


Leading axle fitted, before threading rear axle through frames and gearbox.


Big jump ahead with chassis assembled and brake gear fitted!

I fitted etched axle nut covers to hide the crankpin nuts, but the cover centers do not line up with the wheel centers which could be interesting visually when the lcoos is running.



Loco boiler smokebox and cab-running board sub assemblies.

The firebox is a sliding bayonet fit at the cab end with a 10BA bolt securing the smokebox to the running board at the leading end.

There is a cast brass step ring between the boiler and raised firebox and I have revised the boiler wrapper to form a full circle. 

This photo is a good example of the amount of metal that has to be removed from the boiler firebox  to assemble the loco in OO with the driving wheels literally inside the firebox and boiler.


Loco superstructure and chassis sub assemblies.

The tongue at the front of the chassis fits into a slot behind the buffer beam, the body is secured in place by a bolt that fits through the drawbar and chassis into the cab floor.


I hadn't finalised the backhead/cab floor design when I completed the test assembly.

I have designed separate OO and 21mm gauge backheads and cab floors that can be slotted in place in the cab in a similar manner to the MGWR 2-4-0 kit.

The tender is the  Studio Scale Models GSWR tender with a re-designed chassis for use with a weighted tender system to allow the loco to haul a reasonable load. 


Tender chassis 2mm parallel reamer to remove paint from axle holes/ bearings rear axle.



Tender chassis with temporary wheels showing springing of leading and center axles and axle retaining wire.


Tender chassis brake gear sub-assembly fitted. The goop on top of the chassis is glue residue from a ballast weight.


Tender superstructure, tool boxes and springs.

I decided to fit these parts after rather than before painting the tender, 0.45mm wire pins are soldered into holes in the springs to assist location.


Assembled loco & weighted tender chassis.



98 approaches completion. Buffer beams to be painted number plate and vacuum pipes  & couplings to be fitted.

I have completed the final amendments to the loco CAD work and expect to make an announcement on the expected release date of the loco within the next 4-6 weeks.

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