Chuffer Davies

Surely that's not a science it's an art! I'll get back in my box.....

Hi Tony, you are as always correct. I failed to state a point in my earlier explanation that I have just realised and which possibly better describes the point I was trying to make. On the 4ft radius I suspect you can slide the loco laterally because the radius is still quite gentle by model railway standards. Without side control the loco will tend to prefer the outside of the curve, with side control fitted front and back the loco's driving wheels will be encouraged to follow the inside of the curve therefore you will get a small difference in where the locomotive sits on the track. Having said all that and whilst it is an interesting academic discussion, in the particular case you have raised it is of no consequence. Regards, Frank

I'll message you....

I tried it once and didn't get on with it either. There are easier ways.

Hi Phil, you are correct but there is one other element you are missing. Unless the locomotive is right on the edge of being able to negotiate the radius of the curve then there will be some lateral twist to play with. Without any side control on the trailing axle the cab will swing out as far as it is able to. If the trailing axle has side control fitted then this will encourage the loco to straighten up as far as it is able through the curve. It’s all very subtle and I can hear Sir snoring in the background, but sadose like me love this stuff. Frank

Now that I can agree with. In reality you only need light downward pressure to allow the side control to work as long as the forces are acting below the centre line of the axle. The greater the distance above the centre line the side control acts on the bogie or pony truck the more down force is needed to stop the wheels from canting over and derailing. This is also why, if a loco is nose heavy typical of a 4-4-0, I always mitigate this by hanging the tender on the draw bar which increases the weight on the driven axles, rather than increase the strength of the spring on the front bogie/pony truck which reduces the weight on the driven axles. Frank

Tony, What a super demonstration of how not understanding the physics can lead to false conclusions. I know you’ve written this very much with your tongue firmly pushed into your cheek to see if I would bite, so I have. To explain: When you lift the one wheel on a sprung/compensated chassis the weight you lift is solely that carried by that wheel because the springs/compensation are doing precisely what they are supposed to do. With a rigid chassis when you lift the equivalent wheel you are at the same time lifting all the wheels on that side off the locomotive so the combined weight previously carried on multiple wheels is now transferred to the tweezers hence there is more resistance. To quote you, ‘obvious innit’! Frank

Hi John/Tony, there is something strange happening here. There have been carefully designed experiments to establish whether compensation improves the tractive potential of a model. These were written up in the EMGS Newsletter some years ago. The experiments demonstrated that there is absolutely no difference between rigid and compensated chassis. It’s simple physics, a combination of weight and coefficient of friction acting on the driven axles. In the Retford experiment if the compensated loco needed additional ballast to pull the same train as the rigid locomotive then some other variable must have been at play here. Frank

Hi Chas, Good for you. Welcome to the dark side. Frank

Hi, i’m not sure that pictures will help, it really needs diagrams with explanations. I’m sure there are books written in the past which have already explained the principles far better than I could do. For me the pioneers and exponents of these techniques included Guy Williams and Mike Sharman. I had several conversations with Mike when I was a young modeller but sadly never met Guy. I’ll see what I can find in my book collection and report back. Frank

Hi Chas, As soon as I read Andrew's explanation of the benefits of side control I knew this age old argument would kick off again. There are definitely two opposing camps here with only a few modellers taking the middle ground. As those who have read my postings previously will know my approach to chassis building is definitely at the opposite end of the spectrum to that of Sir, although there is common ground even here when it comes to the importance of building the chassis square and making sure that the coupling rod centres are exactly aligned with the axle centres in the frames. When it comes to side control it is not incorrect for Tony to say that it is un-necessary but I cannot agree that it offers no benefit. A particular case in point for me where side control proved highly beneficial was for loco's shunting the yard on our Hungerford exhibition layout. Initially I could not shunt into the rear siding in the goods yard using a small prairie's front buffers without buffer locking occurring. As soon as I fitted side control to the front pony truck the problem was solved. Before anyone suggests I could have restricted the side play on the front driven axle to achieve the same outcome, I'd already tried that. I can also say with confidence that side control on a bogie does definitely improve the passage of a locomotive through point work. It is only a small incremental improvement, but an improvement none the less and I am very happy to spend an extra hour fitting side control for this small benefit. It can also be the difference between needing to remove material from the back of the cylinders or not. Tony says he is happy to do this as it can't be seen. I personally hate doing this if I can avoid it. Not all layouts are suitable for models built with side control. I anticipate that it is only suitable for, and you will get benefits with, models that are built to run on fine scale track, if you are using Peco points then the incremental benefit will be lost. If your layout has curves tighter than 3ft here again I think you are expecting too much for a model with side control to work. Whilst I always ensure that the models I build will go round 2ft 6in radius I never run them in anger around anything under 3ft. Fitting side control is not complicated but it does require the modeller to take the time to understand the mechanics of it. If its not thought through it is unlikely to work (i.e. derailments will occur). Here again I'm more than happy to take the time to think it through and it gets easier to get it right the more I do it. If you have a personal dislike of side control then don't do it, for me I see the benefit and I will continue to employ it for as long as I model. Back to you Sir.... Frank

Hi Andrew, If you are wanting your locomotives to run on Leicester South then I wouldn't recommend Sharman wheels because of my previous comment with regard their relative slimness. As I have said to you previously, in order to accommodate such a range of wheel standards the check rail gauge on LS is very generous and I suspect you would end up with Sharman wheels jumping the points. The B1 chassis I built for John has Alan Gibson wheels and these seemed to be okay for LS as should be Ultrascale. If they do the wheels you need I'd be happy to help you set them up. If you are sticking with rigid frames then you would need to double check the concentricity of each AG driving wheel before committing them to your model. AG will swap the wheels if there is a problem. Frank

That was what I thought as soon as I saw them. Mike’s wheels are narrower than those of other manufacturers Which is why they look so good. I seem to recall he used the same moulds for both EM and P4 wheels and P4 wheels are normally narrower than EM/OO wheels. I do like Mike’s wheels but sadly I only have a couple of models that use them because he stopped production soon after I started building in EM. Frank

Hi Tony, Many of the techniques I use now were both unknown to me and beyond my abilities 20 or 30 years ago. Thanks to experts such as yourself who are willing to demonstrate techniques and share their ideas (usually at exhibitions), with the knowledge so gained and with a lot of practice I have slowly developed as a modeller. They say that necessity is the mother of invention and this has never been so true as my involvement in the Clayton project. My list is therefore slightly different to yours: For me: 1 - 3. I agree with you. 4. Have I found the best way to overcome any challenges that I might have hit whilst building the model? Keeping things simple is good but a slightly more complicated approach can on occasion deliver a better outcome. 5. Can I use a commercial model or the work of someone else to give me a jump start on my next model? We need 30 locomotives for Clayton. Some of these are having to be built from scratch and so to counter this using a commercial or 2nd hand model as a starting point can be an enjoyable alternative. I would then add to my list: 6. Have I built the model to the best of my ability? And Ideally: 7. Have I been able to develop my skills whilst making the model? 8. Have I enjoyed the experience? What would others put in their list I wonder? Regards, Frank

Ha ha, quite right Andrew, you’ve called me out. The C1 is very much of the ‘rule one’ persuasion. I’ll run it in the club rooms but not at exhibitions. It’s just a very attractive prototype, and that’s coming from a GWR modeller. That’s whyI’ve got an Immingham in my list of locomotives for Clayton. I completely agree with you with regards the potential benefits of side control. I know of several who have tried and failed because they haven’t taken the time to understand the dynamics. Of particular importance is the need for a side control wire to work below the centre line of the axle otherwise it has the negative effect of lifting the wheel on the outside of the curve increasing the risk of derailment. Used properly side control will allow the bogie or pony truck to begin to steer the locomotive into a curve reducing both the tendency of the chassis to twitch as the leading driven wheel hits the curve at the same time reducing the risk of buffer lock. Good to hear from you. Frank

Hi Tony/Andrew, You may have identified a further benefit of the approach I have taken to building my C1 chassis that I had not previously recognised. I experienced no issues with bogies wheels fouling against the cylinders despite using the correct diameter wheels. I think this must be due to the fact that unlike a bogie linked to a chassis by a bar, on my chassis the bogie has no fore or aft movement relative to the main frames. Another feature of the DJH kit which has been overcome by Bachman is that they have provided a rebate in the casting of the footplate to clear the top slide bar allowing the valance to partially obscure it. This photo of the prototype on display at Locomotion illustrates the relationship of the upper slide bar with the valance. Andrew you were asking Tony about the need for side play on the front driven axle. All I can say is that because of problems with clearances between the back of the foot steps and the connecting rods on my model I had to eliminate all side play on the driven axles. Even so, as previously stated, my model happily negotiates 3ft curves so in my experience you won't need any side play. Regards, Frank

Hi again, If you pivot at the bogie centre, unless you allow some side to side movement at the pivot, the model will be far more limited as to the radius it can negotiate. But allowing side play reduces the ability of the bogie to guide the model through point work. In my approach the bogie is actually playing a role in controlling the locomotive rather than just being along for the ride. This is the second time I've used this approach the previous time being on a C12 tank, and both times I've been very pleased with the way the locomotive glides through point work which I believe is the outcome you want to achieve. It does need a bit of thought, and the front bogie wheels need something to keep them down on the track. On my C12 I used a light spring threaded over the centre retaining bolt as there was plenty of ballast in the front of the boiler. With the plastic bodied C1 balancing the locomotive was a more fiddly and rather than a spring I ended up weighting the front of the bogie with lead. Best of luck, Frank

Have a look at this from Alan Gibson. It may give you an idea even if you choose not to buy the actual tool. http://www.alangibsonworkshop.com/RTR Drill.pdf Frank

Hi Andy, Congratulations on a beautiful looking model. With regards the problem you are experiencing with negotiating curved track I have recently had to consider the same problem with a replacement chassis that I've built for a Bachman C1. I suspect that this is too late for you to consider for your model but for anyone else thinking of building one of these in the future my approach has been to extend the fixed wheelbase of the loco by anchoring the rear of the bogie to the main frames directly above the rear axle of the bogie. This does not extend the wheelbase significantly and my model will easily negotiate 36" radius curves (in EM). This approach has several benefits these being: There is no need to provide clearance in the frames for the rear bogie wheels. By effectively making the loco behave more like a 2-6-2 it reduces buffer swing and the risk of buffer locking. The bogie helps to steer the locomotive through the curves. The following photo of the completed frames should help to illustrate how this was achieved. The vertical pin that can just be seen directly above the rear bogie axle is inserted through a plate soldered between the frames and it is this that allows the back of the bogie to control the movement of the frames through the curves. Regards, Frank

Hi Clem, I can confirm that unfortunately Ultrascale don’t do a suitable 6’ 2” wheel. I needed some for my C1 chassis because in EM anything larger would not fit due to the limited clearance of the driven wheels of the prototype. AG does a 6’ 2” LNER profile wheel. Regards, Frank

Hi Clem, Yes they are 14BA. Not sure that the same applies to AG crank pins because they are not interchangeable in my experience. I tried to use an AG crank pin screw in an Ultrascale flush crankpin nut a few weeks ago and it wouldn't go all the way through. I think AG screws are metric (1mm ?) but I could be wrong, I often am. I thought I'd say it before someone else does. Please let me know when they arrive because I'd be devastated if they take longer than the time I suggested to you. Frank

I'm sure there will be many who are delighted to hear the news. I know several excellent modellers who have invested significant time and effort in helping Roy to build Retford and the thought of all their efforts potentially being destroyed was upsetting to say the least. I look forward to hearing more about how Retford is to be progressed to completion. Thank you for telling us Tony.

Lovely work as always Clem. Regards, Frank

Hi Clem, thanks for showing me these, they are just what I was looking for after reading Tony’s response. I knew there must be an easier way. I’ve found some pliers on Amazon and put in an order. I’ll hang on until they get here and try them on the J1 smokebox wrapper. Cheers, Frank

Hi Tony, I still use a half inch diameter brass rod and a slice of mouse mat to roll the main curves of the smokebox and boiler, I have cut the mouse mat into various widths because the wider the strip the more effort it takes to press the brass rod sufficiently to curve the brass to the required diameter. I quite enjoy this part of the build, it is far easier in practice than many perceive it to be. But that reverse curve is a pain. Perhaps if I had a pair of parallel jawed round nosed pliers then that might be the answer. I’ll try and track some down. Thanks to Paul and yourself for your help. Frank