Graham's Caledonian scratchbuild

[agt613]

I have been encouraged by Steve (Londontram) and others to describe the building of a CR Brittain Oban Bogie. I have returned to modelling after a 40 years' absence bringing up a family and travelling the world in my work as an academic in housing policy in developing countries. I modelled the Callander and Oban Railway in my teens, starting a Class 55 4-6-0 Oban bogie then and 'finishing it' currently. I have a small stock of scratch-built wagons and a few unfinished panelled coaches but no layout (YET).

 

I have a drawing kindly provided by CRASSOC, even though I am not a member. I'm not sure about including an image of it here so will ask them and include it later.

 

The Brittain Oban Bogie presents an interesting and fundamental issue - there is no continuous footplate as the cylinders and slidebars protrude above footplate level. Thus, a nice flat footplate as a foundation for the build is not an option. In addition, the drawings are of the original while all the photos I have (all of four) are of the rebuilt version which is in my period. The most noticeable difference is a bigger boiler (4'6" I think) which makes superstructure assembly a bit of an iterative process.

 

Added to this, the bogie wheels have splashers which obviously travel side-to-side with them. I'm not good with bogies and clearance so decided to have a joint bogie and chassis unit, separate from the main chassis, which follows the curves in the track. I will see how it goes. Any opinions or experience of such a solution would be welcome.

 

I made a set of frames for the area between the drawbar and the sandboxes which sit behind the bogies. This will contain the driving wheels, the skeletons of cylinders, etc., and the motor. My rather shaky image shows the chassis so far. The frames are pretty standard shaped with 18 thou brass sheet soldered together for marking and drilling. I use a black marker pen (berol multipurpose) to scrape cutting and bending lines on and use the scoring with craft-knife method for thinner brass sheet which gives a beautifully clean break line. My friend with a vertical drill helped to get the frames true and we used his huge soldering iron to fasten it all together, checking it on a mirror for level.

 

The wheels are Romfords. Why did I fear the difficulty of getting true driving wheels? The Romfords are dead true and quarter themselves (as long as I remember which side leads). I assume the right does. Is that correct?

 

I decided to try a fold-up method for the footplate (rear three-quarters), splashers, and cab side. This was marked out and cut leaving the splashers larger than necessary for careful fitting later. I have made the decision to have correct 5'2" wheels and use slightly oversize splashers to cope with the flange oversize. I'm toying with plasticard splasher tops to minimise shorting. Any opinions on this out there?

 

I decided to try Romfords threaded crankpins but my connecting rod is too small for the larger hole needed so will make do with unthreaded. This delays the time to fasten it all up. The masimo motor has a 54:1 gear train from Highlevel. My first attempt but much helped by threads on rmweb and elsewhere. I couldn't agree more with the admonishment to read the instructions at every stage. I rigged up some pickups and found it worked OK. The piston and slidebar assembly (from Markits) all seem a little stiff but I hope they will ease in use. I don't know if the slide bar is correct but it is mainly hidden behind the solebar (only 1mm deep so not much strength available there!)

 

I've added a flat plate forward of the cylinders as a basis for the front end.

 

That's it for now. I hope some members will find it interesting and would benefit from hints and tips.

 

Thanks for reading it, Graham

[agt613]

Having been given permission, I can now add the drawing for which the Caledonian Railway Association owns the copyright.

[Londontram]

Hmm more Caledonian loco builds I'm going to look forward to this but its got to be said you've picked a tricky one to start with what with the cylinders coming through the running plate. I've heard the top front of the cabs are a hard shape to get right and I believe people who have built this type and similar locos make up the cab and leave the front as a solid block of solder and file and sand the double curve into this.

 

   I'm looking forward to seeing how your solution to the bogie and splashers works. Keep up the good work Graham I'm already looking forward to your next update.

                                   Steve

[jasp]

I have a kit built Brittain Oban Bogie and have, like another extremely fastidious modeller friend, not fitted bogie wheel splashers.

We both model in P4 so there is virtually no clearance for splashers.

London Road models have a CR 123 which appears to have cosmetic bogie splashers attached to the footplate which might be a solution. I should emphasize that I have not confirmed this with LRM, but looking at their demo model it looked like that

Good luck with your build. I look forward to seeing your progress

Jim P

Edited April 20, 2016 by jasp

[agt613]

I have a kit built Brittain Oban Bogie and have, like another extremely fastidious modeller friend, not fitted bogie wheel splashers.

We both model in P4 so there is virtually no clearance for splashers.

London Road models have a CR 123 which appears to have cosmetic bogie splashers attached to the footplate which might be a solution. I should emphasize that I have not confirmed this with LRM, but looking at their demo model it looked like that

Good luck with your build. I look forward to seeing your progress

Jim P

Thanks Jim. Who makes a kit? I am hoping that the chassis part of the bogie area can swing against something smooth under the footplate so the clearance will be gained up there rather than round the wheel arches. The splashers can then move with the bogie and chassis together. I'll build in some vertical play in the bogie to which the splashers will be fastened. I hope it will work.

 

Thanks also Steve (Londontram). It isn't my first build. I have built the 55 class,  I have made a start at the cab front as I needed it to see how the larger boiler would fit. It as all a bit trial and error. My current experiment is to cut the front too tall and then snip down to the top of in so many tabs, using scissors. I have then curved these letting them overlap as they fall. I have tinned the inside to text the method and will cover the outside with solder the same and file it to shape - I hope it will turn out to be a surface mix of mostly brass and some solder infill. That's the plan. The inside might have to be the concave version of the above. Then the curved roof can be butted up.

Edited April 20, 2016 by agt613

[Blandford1969]

Nice build of a rare prototype, it would be lovely to see your class 55 too.

[Londontram]

 

Thanks also Steve (Londontram). It isn't my first build. I have built the 55 class

Sorry Graham of course you did, I meant the first one to feature on your build thread.

 

  Be careful about sitting the top of the bogie against a smooth surface on the underside of the chassis or running plate I tried something along these lines when I first did the rear bogie on the 104 tank and found it greatly affected the traction on the rear driving axle so went to a more free floating bogie, it now has about 1mm of clearance between the top of the bogie and the underside of the chassis so all the loco weight sits on the driving wheels.

                    Steve

[agt613]

Thanks for the advice ,Steve. Well taken.

[agt613]

Nice build of a rare prototype, it would be lovely to see your class 55 too.

Here are two rather fuzzy pics. Sorry for the quality. Thanks for your interest. Graham

[Blandford1969]

Super, you cant beat a nice class 55, of course the one Oban bogie that is the rarest in model form is the 191, Look forward to seeing your build progress.

[Sandy Harper]

Are these of any help? I have some others if they will be of any use to you.

 

Regards

Sandy

 

 

 

[agt613]

Wow, Sandy, it is fabulous. Such detail. Do tell me it's 0 gauge and not 00. One thing. My photo of the rebuild from front quarter shows the boiler sitting much higher. Is this the non-rebuild?

[Blandford1969]

Would a photo of a withdrawn example be of any use. I've got at least one negative somewhere?

[agt613]

Yes, great, Blandford 1969. Any help is gratefully received.

[Sandy Harper]

I don't know how you work in such a small scale! Yes, it is '0' gauge.

 

The photo shows how I received it and I suspect that it was originally a kit but where from, I have no idea. It certainly looks like the original version with the smaller boiler.

 

Regards

Sandy

 

[agt613]

Yes, Sandy, It is the original version. On the one you received (post ~15) the dome is forward of the more central position of the rebuild. Your improved one (post #11) is also modelled the original boiler, I think, but the chimney and dome are where they were in the rebuild. The front-quarter photo I have of the rebuild (the number is in the 1100s - 1183, I think, whereas before rebuild they were without the thousand digit) has a space underneath the smokebox front equal to almost half the smokebox door's diameter. On it, the cylinder covers (rectangles riveted on the base of the front both sides) have at least their own height of empty space before the bottom of the smokebox door. The latter is at the same height as the frame's apex.

 

I've begun to agree with you about modelling it at 00. The cylinder assembly is a real pain to get right. I may switch into plasticard for it. In addition, it reduces the chances of having a nice firm base to the body as there is only the merest suggestion of a footplate above the slim solebar. I have resorted to building the basic shapes behind the cylinders as a cut and score fold-up exercise. The picture shows an early incarnation with the connecting rod splasher side, driving wheel splasher side and cab side all cut and folded. There is one of these for each side. The splashers are deliberately oversize and will be filed down to fit.  I may use plasticard for the splasher tops.

I'm having a bit of a tussle getting the whole thing horizontal at footplate level, currently it sticks its nose up somewhat and squats down at the rear. It's all an interesting learning curve!

 

I won't be doing much for the next two weeks as my beloved and I are having two nights at a posh hotel and then I'm going to Iran for a week. I am hoping to tackle some of the bogie assembly while abroad and hope Iranian customs are OK with a modelling knife and plasticard as I'm hoping to add plasticard splashers to my brass frame. They should protect the wheels from shorting out on the frame. My original idea of having the whole front frame pivoting as one is filed under abandoned, following advice above.

 

Thanks for travelling the route with me. Please comment where helpful

[Sandy Harper]

I built a Jones tank 4-4-0 some time ago and made the chassis cylinders and smokebox as one unit and had the split for the remainder of the body and footplate immediately behind the smoke box. I also restricted the rear  bogie axle side play to zero lateral movement, and made the bogie pivot point behind the rear axle but allowed side play in the front drivers making it a 2-6-0.

 

I seem to have mixed an original boiler with rebuilt fittings. Don't tell anyone, they'll never notice!

 

Sandy

[Horsetan]

....I'm going to Iran for a week. I am hoping to tackle some of the bogie assembly while abroad and hope Iranian customs are OK with a modelling knife and plasticard ....

 

They may ask questions about this type of thing - I don't think railway modelling has quite taken off in Iran yet.

 

Still, hopefully you won't cross the path of the Revolutionary Guard. They tend to go a bit nuclear.

[agt613]

They may ask questions about this type of thing - I don't think railway modelling has quite taken off in Iran yet.

 

Still, hopefully you won't cross the path of the Revolutionary Guard. They tend to go a bit nuclear.

Ho ho, Horsetan.

 

Visa issues are raising their ugly heads. May not get there after all. I did get to the Simla railway on a work trip to India, once! And saw beyer-garrets crossing the Zambezi on the Victoria Falls bridge in the seventies. Awesome.

[agt613]

I built a Jones tank 4-4-0 some time ago and made the chassis cylinders and smokebox as one unit and had the split for the remainder of the body and footplate immediately behind the smoke box. I also restricted the rear  bogie axle side play to zero lateral movement, and made the bogie pivot point behind the rear axle but allowed side play in the front drivers making it a 2-6-0.

 

I seem to have mixed an original boiler with rebuilt fittings. Don't tell anyone, they'll never notice!

 

Sandy

The 2-6-0 idea is a great one. I'll look into it. Must check how much side play the front driver has.

 

Thanks, Graham

[agt613]

Hi Folks,

 

Some progress can be seen in this trial and error build. The parts are just placed on at present but it shows something of what it will be.

 

The chassis has had brakes added (never would have thought about it when I modelled before) and await the hydraulic (?) pushers in a Y shape to keep them in the right place. The brake hangers and shoes are tender brakes from NBR models filed down a bit. The lower part of the lever is fitted to the rear wheel brake both sides. The right hand side (from the front) still needs the splashers cut down to size and the cylinder coverings. One splasher has the drawing stuck to it as a datum but it will be larger to accommodate the over-sized flange. I may use 5 thou plasticard for the splasher tops to avoid shorting. The body side is slightly out of horizontal so will need at least 20thou under the cab. This side is attached to the footplate front which includes the rather super curves of the front frame They are bent up from the footplate floor on both sides and a centre piece added. This was originally part of the smokebox front but had to be separated as measurements didn't quite suit.

 

The cylinder covers have been added but removed again until the whole footplate is in place. It's all rather tight across them from one solebar to the other. They fit in with the coupling rod splasher front.

 

I have added the bogie with frames to suit their splashers. These will be plasticard and added to a dummy frame on the outside of the brass frame and inside the wheels. The wheels are just slotted in at present. I have used a square frame spacer from Markits as it adds both stiffness and weight. The bogie currently pivots on the centre frame spacer by a long bar but that might change.

 

The other side is ready to add when I get the splashers filed correctly and then I'll fit the cab front.

 

I am really enjoying working with metal, watching solder flow is a beautiful thing. I'm taking the tender drawings, some 10 thou brass and a few tools with me to Iran on Monday for my first overseas modelling session. I hope to bring back the parts for the tender frames, footplate and sides ready to solder. Getting downward tabs for the frame sides and upward for the body fitting will be an interesting challenge. Let's see what the week there brings.

 

Thanks to you for all your encouragement for this renewed modeller. Graham

[agt613]

Just encountered a problem.

 

Background: My drawing is for an unrebuilt 179 Oban Bogie but I'm building the rebuilt version with a larger and higher-pitched boiler. The key dimension to determine where the new boiler fits in the vertical is the apex of the arc that touches the bases of the spectacle plate windows. The boiler must fit there.  

 

I have soldered the cab front and roof on and now have to get the boiler horizontal by making sure its height at the front (plus the thickness of the smokebox wrapper) matches its height when it fits snugly between the spectacle plate windows. This give me about 19mm of height. On my photos of the rebuild, the boiler centre line appears to be 60 per cent up the front. If I file down the current smokebox front to 19mm, I'll have 10 mm below and 9 above - not 60:40 at all. I'm heartened by Sandy's "Don't tell anyone, they'll never notice!" but I also have the problem of hunkering the smokebox down between the frames where it's too wide to go! Time for some bodging and more of the art than the engineering.

 

Back to the cab. Its doubly curved front promised to be a brute but I have tried a simple method which can be seen warts and all on the photos.

 

I cut the cab front oversize at the top and then cut down, with scissors, the 10thou brass sheet into lots of tabs which overlap because of the scissors' twisting action. When curved in one each other, they were filled with solder inside and out and roughly filed to see if it was working. Having soldered this to a curved piece for the roof and added more solder, it's ready to file to its proper profile and clean up the solder. It seems to have worked so far.

 

I've also just discovered solder wick to get the beastly stuff off where it's not wanted. What a miracle it is!  Highly recommended. Amazon delivered it in two days post free.

 

Thanks for reading. Tomorrow I have to fly to Istanbul where I must spend a day at the Iranian embassy betting a visa for Iran. Then another couple of flights and a road journey to my destination in Kurdish Iran. Back on Saturday, God willing! I'm getting too old for this. I hope to come back with the major tender bits ready to solder. Any advice on taking a flared top round corners, I've forgotten how I did it with the 55 class 45 years ago. Plus the 179 tender seems to have a curved flare. All advice gratefully received.

 

Best wishes to all, Graham

[Sandy Harper]

Graham

The trouble with scratchbuilding and working from drawings and photographs is that it doesn't take into account 00 gauge frames. From your photo it looks like the front frame extensions, above the footplate are in the same plane as your 00 frames below the footplate, whereas they should be outside of that dimension. This would allow your larger boiler to 'sit down' at the front end between the widened frame extensions. If I have understood your question correctly!

 

Regards

Sandy

[agt613]

Graham

The trouble with scratchbuilding and working from drawings and photographs is that it doesn't take into account 00 gauge frames. From your photo it looks like the front frame extensions, above the footplate are in the same plane as your 00 frames below the footplate, whereas they should be outside of that dimension. This would allow your larger boiler to 'sit down' at the front end between the widened frame extensions. If I have understood your question correctly!

 

Regards

Sandy

Thanks, Sandy. No, my upper frames are prototype width, wider than the 00 frames, and still the smokebox is pushing at them where the sloping frame top meets it.

[Sandy Harper]

Thanks, Sandy. No, my upper frames are prototype width, wider than the 00 frames, and still the smokebox is pushing at them where the sloping frame top meets it.

Studying your photo more closely, I can see that now. I'm at a loss to suggest anything else.

Sandy