The Caffeinated Engine Driver

It's been three years since I first started work on a model of Clayton #5843, and in that time I've worked on three different models. The first had issues around the print bending and was never finished. The second was built for running on Rhyd but balance issues meant the heavy pewter driver figure caused the loco to kangaroo along the track, so he had to be replaced by a plastic figure. I've now finally finished the third iteration of the model (another commission so I've still not built one for myself) that includes more weight and finally allows the nice pewter figure from Andrew C Stadden to take it's place in the "cab".

It's new owner has requested it in ex-works condition (so they can have it weathered to match existing stock) and so here it is fresh from the paint shop.


While it would benefit from a little more running in (difficult on my short O14 test track) it's running a lot smoother than previous versions with the driver figure on board and is showing no sign of bouncing along the track.


Now I really should get another set of parts together and build one for myself, but first I'll need to take a trip to the post office to get this one on the way to its new home.

Having spent some time over the weekend when the little one was asleep doing some work, I managed in return to get a little noisy modelling done yesterday while he was at nursery; I do love having a job that allows me flexibility in when I work as long as the work gets done. The result is that I've managed to move the Clayton O14 loco build along a little to the point where it's now moving under track power.


The downside of more weight is that there is even less space inside than before so I had quite a few problems with electrical shorts, but after some careful tidying and some electrical tape in key areas it moves. Clearly the wiring is just temporary; there isn't room in the loco for all that spare wire but I've left everything nice and long until I sort out the lights and will wire everything up properly in one go at the end. The pickups possibly also need a tweak here and there to improve running, but I'll probably do this once the model is painted as they'll only get knocked when the wheels are dropped out etc. The good news is that with the extra weight introduced in this version it seems to run nicely, although I'll only know for certain how it performs once I try adding the rather heavy driver figure as that was what caused the most problems last time. For now I'm happy with how it's coming along though.

Whilst assembling the model I did briefly ponder another change from the previous version. I managed to accidentally assemble the model without fitting axle bearings. The result, as you can see in the video, was that the wheels were free to rotate slightly around the centre line of the locomotive.


Many models are actually designed to incorporate features similar to this, usually refereed to as a compensated chassis, to help the wheels maintain contact with the track at all times, and hence to ensure proper power collection over points etc. While I did briefly ponder leaving the model like this I decided not to, simply as I was worried that the plastic gear would suffer terrible wear against the stainless steel keeper plate, but has anyone done anything like this before? Any thoughts on how successful or terrible an idea it is?

As some of you figured out the new parts I showed in the previous post are a revised version of the keeper plate in the O14 Clayton battery electric locomotive I've been modelling on and off for the last two and a bit years, having started on it back in May of 2015. I did finish a complete model at the end of 2015 but that is now earning it's keep in Rhyd. Initial running trials at Rhyd showed that while the model worked okay it wasn't really heavy enough, especially if the driver was on the heavy side, and had a tendency to bounce. For the past year I've been slowly thinking about ways to add more weight and this is the result.


On the left we have the original keeper plate as fitted to the model now running on Rhyd. In the middle we have the revised keeper plate which is quite a bit thicker and has much taller ends. On the right we then have a new part which is purely to add weight; it doesn't have any specific function, unlike the keeper plate. This fits between the motor and the layshaft directly over the wheels.

The original keeper plate weighed 6.3g whereas the two new parts together weight 14.8g so an extra 8.5g, or viewed another way, an increase of 135%. Hopefully this should drastically improve the running quality of the model by helping to keep it securely on the rails. Hopefully I'll find out reasonably soon how much of an improvement as I need to get on and build the new model because, yet again, I've been commissioned to build it for someone else, so I still won't have finished one for myself!

As a bit of an aside, and because I think it's interesting, I thought it worth a few comments on weighting models and I why I've taken the route I have. Often when trying to add weight to models people use Liquid Gravity which is essentially a lot of tiny little heavy beads; would probably have been lead shot at some point in the past but health and safety rules means it's no longer lead based.

Liquid Gravity is nice and easy to use as you simply pour the beads into the available space within the model and keep it in place with a little superglue. I used this approach when building the Hudson-Hunslet model as it meant I could fill the tiniest of spaces to add extra weight. While the manufacturers don't provide any details on the weight of Liquid Gravity for a given volume I did find a review that had tried to estimate how heavy it really is. They found that it weighed roughly 4.15 g/cm3 which is actually quite light when compared to lead which weighs 11.3 g/cm3.

The stainless steel that I've had the parts 3D printed in is referred to by Shapeways as being 420 steel. Having had a hunt around I've found that 420 steel should have a weight of 7.74 g/cm3; so an 86% increase in weight for the same volume. Shapeways also give the material volume of each part and checking I found that the original part (with a volume of 0.8141cm3) should have a weight of 6.3g and the new parts (with a combined volume of 1.8215cm3) should weight 14.1g which matches nicely with the final weights of the printed parts.

When building such small models it seems silly not to take advantage of the extra weight of the stainless steel especially given that it can be printed to exactly fit within other printed parts and, in the case of the keeper plate, to serve a function at the same time. I'll certainly by continuing with this approach on future models, although Liquid Gravity still has it's uses.

When I built my first working point at the beginning of December I mentioned that I was intending to build another one to see if relying on the rail flexing was a better approach than hinging the rails. I actually built the second point quite soon after but for some reason didn't post about it. Anyway here we have both points next to each other with the new version no the left.


So how does allowing the rail to flex compare to using hinges? Firstly aligning the rails accurately and getting a nice smooth curve through the point was much easier the second time around. Partly this was down to having a better idea what I was doing when shaping the rails but also as I could use the rail gauges to position and hold the rails in place while they were soldered on which was easier than holding them in place and drilling holes for the hinges. On the down side though I'm honestly not convinced by the motion of the point. Firstly as the rails are flexing I've ended up with a point that when left alone sits with the tie bar half way between the two routes. Secondly keeping the point one way or the other requires quite a considerable amount of force.

So in conclusion I'm going to stick with fitting hinges to the points and hope that with more practice the flow of the rail will improve slightly over the first attempt so I'll have both nice looking points and points that require little effort to operate.

Thanks to a local reporter (i.e. David the owner of Rhyd) news has reached me that the Clayton arrived safely in Rhyd after the long road journey from Sheffield.


By last Saturday she had been unloaded onto a flat wagon for the journey up the quarry tramway.


The battery was charged and she was given her inaugural run up in the mountains.


After running in she will be entering the paint shops - but she will be back in service long before Model Rail Scotland in February.

So having given you a few days to think about the mystery 3D printed objects I'll put you all out of your misery. They are jigs to help cut rail at the correct angle for making Hudson Type 1 and Type 2 points in O14. While I have the KBscale jigs for actually soldering the rails together they rely on you cutting or filing the rail ends to either 15 or 9 degrees and I found doing this accurately was a bit of a nightmare and so a jig or two sounded like a good option.


The printed jigs are actually the third iteration of the basic idea which was to trap the rail in such a way that a razor saw could cut it at the given angle. The first attempt, which I've unfortunately thrown away so can't show you, used four pieces of 4mm square section styrene stuck to flat sheet, two on each side of the rail. The pieces on each side were offset so that you ran the saw across the rail resting it against the ends of the blocks. It worked well enough to produce the first crossing I made but it wasn't easy to hold the rail still while pushing the saw against the blocks.

The second jig used 12BA nuts and bolts to both clamp the rail and to help position the saw. The screw holes being carefully positioned so that they both allowed the nuts to grip the web of the rail, but also to act as the guide for the saw. While this was much better at keeping the rail in place it was still difficult to keep the saw in place against the upright screws, there was a danger of sawing into the nuts, and the cheesehead screws meant that the jig wasn't very stable on the worktop. It did, however, allow me to build two Type 2 point without requiring any extra filing of the rail ends.


The printed versions continue the idea but without relying on the screws to guide the saw. The two printed parts are used to clamp the rail in combination with grooves in both halves. The slightly bendy nature of the strong and flexible plastic is actually really useful here as it allows you to really tighten the jig so that the rail doesn't move at all. The saw then fits within in the guide formed between the top part and the block on the bottom half making it much easier to cut the rail.


I haven't had a chance to build a point using the new jigs but I have cut a couple of rails to check that they work and they appear to work very nicely which should make it easy to churn out more crossings in the future.

So here we are, the last post on the build of this the third Clayton prototype (the second never got made up but allowed me to test the keeper plate). The driver is now in place which means the whole loco now weighs in at 34g. Possibly a little light for an O14 loco but there isn't much space to add extra weight.


Obviously it's not entirely finished as it needs painting and the name and works plates fitting but these will be left to David as my painting skills aren't up to producing a loco that would fit in well with the quality of Rhyd. It seems strange packing it up to send it off to it's new home as I've never built a model for anyone else before. Hopefully David will enjoy it and if you see Rhyd at an exhibition you might even see the Clayton working the quarry tramway. For everyone else here is one final video of the loco in action.

One of the first comments I received when I announced I was working on a model of the Clayton was that the light mouldings really were crying out to be fitted with working lights, and who am I to refuse such a sensible suggestion. The problem is that while the mouldings are big in relation to the size of the model they still aren't very large. Fortunately LEDs are available that will fit but they are very very small.

The smallest surface mount components I've used before are the resistors in the Hudson-Hunslet, which come in a 1206 package. They are known as 1206 as that is the imperial measurements of the component, i.e. 0.126" by 0.063" or in metric just 3.2mm by 1.6mm. For the lights on this loco I've had to go for LEDs in a 0402 package which is 0.039" by 0.020" or an eye wateringly small 1.0mm by 0.5mm. Given that those dimensions are for the entire LED you can probably imagine just how small the two contacts are that you need to solder wires to. My eyesight for close work might be quite good and I have a brilliant magnifying lamp on my desk but I don't think I would have the patience or dexterity to wire these up. Fortunately you can buy them pre-wired on eBay! This helps but the wire itself (referred to as magnet wire) is also ridiculously thin so it's still a fun challenge wiring these up.

Of course there isn't just the LEDs to wire in, but a resistor to protect them from the full track voltage (2.2K Ohm in this case) and a capacitor to help reduce flickering all of which need to be connected together and then stuffed into the small space behind the motor.


As you can see there is quite a bit of stuff, even if some of those wires were trimmed back before I finished) to get into the body so there was a fair amount of careful stuffing involved. Once the body was on the result though is this.


I could probably have used a slightly bigger resistor to drop the brightness a little further but for a loco that originally worked in a long dark tunnel this seems okay, and a bigger value capacitor might have reduced the flickering a little further, but in general I'm really happy with the result.

After a break of afew days due to visiting family I'm now back to building the Clayton loco and fortunately, given the little time remaining to post it on Monday, things seem to be going quite well, although the carpet monster did eat the small pulley although it then spat back two 1.5mm bearings! Anyway here is the current state of play.


The main job today is to fit and wire up the lights, and then I can add the final body details. Then tomorrow I need to finish the driver figure and to give the whole thing another good test run.

One of the parts I had to redesign from the second prototype of the Clayton was the stainless keeper plate. If you remember I'd managed to design it 0.2mm too wide and reducing the width by hand was a nightmare due to the strength of the stainless steel. So I altered the design to remove 0.1mm on both sides, and opened out the screw holes slightly for an easier fit. The larger holes meant a change to the rebate for the head of the screw as well.


As you can see the changes worked well and everything fits together nicely. The two bolts are lightly glued into place just to make sure they don't come loose, and while the layshaft is now fixed in place (the two worms are fixed to the layshaft with Loctite which holds everything firmly in place) everything else is removable just by undoing the two retaining screws. Next job will be to strip it down again, and fit the pickups and associated electrical bits so that I can get it running up and down my test track.

A quick update on another detail for the Clayton loco, this time it's the bell.


I don't think I mentioned this on the first prototype build but I've produced it in the same way by soldering a 4mm pinpoint bearing to an etched stand. Nice, simple, and fairly convincing from normal viewing distances.

After spending the day with friends I've done a little more on the Clayton build, specifically the rather fiddly brake leaver. This bit hasn't changed since I built one up for the first prototype so it still consists of eight tiny etched parts on a piece of 0.33mm nickel silver wire. Last time I found getting the front and back layers, which slot through the 3D printed body, aligned and straight very difficult, so the tool I included on the etch this time has two slots to make assembly easier.


So building the brake lever basically involves slowly laminating seven of the eight parts using the wire to help align them as well as keep them together. I pas the wire through a hole in piece of wood as well to help keep everything still while dabbing at it with a hot soldering iron. The eighth piece (the front support) is then threaded onto the wire with some solder paste on the wire and the whole thing then slotted into the etched tool to make sure the front and back supports are properly aligned. A quick touch of the soldering iron then fixes the front support in place and with the slots in the tool being the same as on the 3D printed body the completed brake just drops into place.

The tool also has a third use, in that the sticky out bit on the end can be used to make sure all the slots in the body are clear of wax support material so that the pickups, brake, and bell stand will all fit without being forced.

If you've been following along for any reasonable length of time then you'll know that the main area that seems to trip me up building or designing model locomotives is getting the pickups to work properly. On the Clayton loco I think I've hit on a fairly good way of fitting the pickups where what looks like a staple of phosphor bronze strip is pushed through slots in the model from the inside with the ends then bent back at an angle against the outside of the body so that they rub on the rear of the metal wheels. The problem is accurately making the initial staple shape so that it fits perfectly as that helps with setting the tension of the pickups which if not right can affect the running of the model.

On the first prototype I folded up the staples by eye and while they were fairly good they weren't a perfect fit. With the addition of the keeper plate and retaining screws this is even more of an issue as I need to make sure the pickups are flat on the inside so they can't short against the screws. To help with this I designed an etched part to act as a forming tool (it actually has other uses so you'll see this part again).


The tool works well and as you can see the fitted pickup lays nice and flat against the inside of the body so it was well worth adding the tool to the etch. Hopefully it's other use will prove as successful but you'll have to wait a little to find out.

I've now made a start on building the third Clayton prototype. I'm still waiting on the etched parts to arrive (they've been posted so blame Royal Mail) so while I can't start on the body yet I can get to work on most of the mechanical aspects.

One of the main changes from both my approach to designing the Hudson-Hunslet and the first Clayton prototype was the decision to use a keeper plate and to assemble all the drive components outside the model. This means I can put together the layshaft and the wheelsets in comfort without having to try and fit everything together inside the body.


Compared with trying to fit gears inside a body this is so easy that I'm never going back to the old approach unless forced to do so for some reason.

Having now recieved my order for more rail I've continued on with my O14 point building experiment. The first attempt was for a very tight Type 1 point which in retrospect was going to be a struggle even for short wheelbase locos so for my second attempt I've switched to the slightly less severe Type 2 point. Of course with more rail to hand I've gone a lot further than just building the central frog section, in fact I've built an entire point.


I've deviated from the suggested instructions in quite a few places though as I've built the point onto copperclad sleepers rather than the suggested plastic sleepers. This meant that I had to gap the rails to ensure that the polarity of the frog could switch when the points changed. I also simplified the tiebar slightly by not trying to fit nice looking plates and rivets but using a bit of wire instead. Of course photos on their own don't show you if any of this was successful or not so here is a video of me testing it.


So yes it does work, but I'm not entirely happy with it. Mostly I'm not happy with the hinges. Drilling the holes to make the two parts of the rail line up properly was a real pain. So having recently seen someone else build one without hinges where they relied on the rail flexing instead I'm going to have another go and see if that is a better approach. Still not bad for a first attempt.

Late last week I had a delivery from Shapeways which contained the next iteration of the parts for the O14 Clayton battery electric loco I'm working on. This is now version three of the design and it looks like I've solved all the outstanding problems with the previous version.


The main differences are to the way the parts fit together. Firstly I've narrows the steel weight slightly (which involved changing the shape of the cutouts for the screws) so that it will fit inside the body without distorting the sides. In the previous design the two main parts of the model were mostly held together as a friction fit, but only along two small surfaces (the back and front of the top piece fit against the front buffer beam and the front of the driver area). In theory this was enough, but often the parts would warp ever so slightly during the printing process and although they would hold initially would spring apart just by sitting there. Also if viewed from low down there was a slight visible gap between the two parts above the wheels.

I've solved the problem by adding more material to both parts to increase the surface area of the interlocking sections. This means there is now a block on the bottom of the upper part that slots between two of the supports in the bottom half to keep the flat rear area flat. To make sure the front part stays together, and to get rid of the slight gap, I've extended the body sides upwards so that they fit inside the top half by a couple of mm. This seems to work so well that once the parts are together they require a fair amount of force to separate. Combined with the retaining screws it looks as if it will be a nice solid model once I've built it up.

Talking of building it, this model is going to be a little different to every other one I've built as once it's running it will be packed up and shipped off to it's new owner. When I was visiting ExpoNG I spent a very enjoyable evening drinking beer and talking railways with David John the builder of the wonderful O14 layout Rhyd. He was really taken with the first prototype of the Clayton and has asked me to build one to run on the quarry tramway. Normally I'd have waited and built up another print rather than what is in essence a prototype model, but as it is destined to be one of David's Christmas present I don't have time to order more parts. It will also be heading to David unpainted as I feel that my loco painting skills (wave an aerosol can at it) fall well below that of the other locos on the layout. Anyway David has kindly agreed that I can document the build and hopefully at some point there will be photos of it earning it's keep on Rhyd.

I've really enjoyed working in O14 building the Clayton loco, but if I want somewhere to run the loco that isn't a simple straight bit of track I'm going to need to build some points. When I was at ExpoNG I picked up both the Type 1 and Type 2 crossing jigs from KBscale in preparation for this but it took until this weekend to find time to have a go. Even with a jig to help hold all the parts it's still quite tricky (or maybe I just haven't had enough practice). The first problem is finding a reliable way of cutting/filing the ends of the rails at 15 degrees. In the end I built a small jig from styrene which seems to do the job but it feels like there should be an easier way. Once all the rails have been cut and fitted to the jig the problems don't end. Because the jog is metal it's impossible to get enough heat into the join with my soldering iron as it just soaks into the jig instead. The trick is to use the kitchen blow torch (usually used for creme brulee) to pump in lots of heat.


Once it's cooled and cleaned up it looks as if it will do the job nicely. Unfortunately I then cut the rails back but measured badly so they are too short for the type 1 turnout I was trying to build. Not to worry though as the practice was well worthwhile. Unfortunately I seem to be almost out of the PECO IL-115 rail so will have to order some more before I can have another go. Also looking at the instructions I'm not sure I like the suggestions for hinging the switch rails (a wire down through the sleeper). I'm wondering if I can just do without a hinge and rely on the slight flex of the rail, but that experiment will have to wait until I get some more rail.

The way I produce the models that I 3D print allows me to work down to an accuracy of 0.001mm. Of course it's highly unlikely any printing process will be so accurate but so far when I've printed models in multiple pieces they have always fitted together perfectly. I was surprised therefore when I tried to put some of the second Clayton prototype together to find that I didn't have a perfect fit. The problem was that once I'd fitted the bearings to the FUD print the stainless steel keeper plate wouldn't fit without distorting the body. You can see this in the left hand photo.


What confused me was that the stainless steel part measured out at exactly 9.10mm on my digital callipers which matched the 3D model perfectly. As I mentioned before the stainless steel is seriously tough and it took ages, even with a diamond file, to reduce the width sufficiently to allow things to fit better (the right hand photo). Altering the 3D model to narrow the steel part slightly for future models is easy but I wanted to work out not only how much to narrow it by, but why I needed to.

When I develop a new model I produce virtual copies of all the other parts (wheels, bearings, motor, etc.) that I'll use to help me visualise how everything will fit together and to ensure adequate clearances etc. On this occasion though it appears I managed to wrongly measure the flange on the wheel bearings. My model of the bearings has the flange at 0.1mm, turns out having remeasured them that they are actually 0.2mm which means that the keeper plate is 0.2mm two wide. I know 0.2mm doesn't sound like much but I suppose that just goes to show how accurate the 3D printing process is.

After the mostly successful completion of the 1st prototype of the Clayton locomotive I made some changes to the design to solve the problems I encountered as well as to make the loco easier to assemble. The parts for this 2nd prototype turned up today. As you can see I've doubled the number of components from two to four and not everything is printed in FUD.


One of the main design changes was to allow the axles to be completely assembled before fitting to the model which led me to the idea of a keeper plate, which also has the advantage of stopping the axles from shifting sideways which is what was causing the jumpy motion on the last prototype. Now I could have had the keeper plate printed in FUD but instead I've had it printed in stainless steel as this nicely adds weight to the loco; 7g of extra weight to be precise. The only problem is that the steel is exceptionally tough and the holes for the screws that will hold it in place ended up printing slightly under size. Opening them out has caused me to break a drill bit, draw blood, and I now have a blister but.... everything now seems to fit together!

I also made the control box as a separate piece so that not only is it easier to paint the model but it can hide the nut that holds the upper and lower parts of the model together. Unfortunately the footplate is still a little bowed and while I did make the fit tighter at the front it's still not perfect so unless I can flatten the part out a little (soak in hot water then hold flat while it dries) I might need to think about a better fixing at the front as well (harder as the pulley for the drive belt is in the way).

I've had to start packing most of my modelling stuff away as we are having family to stay at the weekend so I'm not sure when I'll get to try and put this together but hopefully I'll be able to find some time to at least assemble the axles and make sure the keeper plate works properly.

Other than adding the makers plates I've finished the first build of the Clayton loco I've been working on. As I mentioned before there are more things wrong with the current version than right but it's still assembled into a passable model.


I've rally enjoyed modelling on O14 as the larger scale has really let me go to town on the details. Not only do we have the brake lever from a previous post, but individual wires and a bell among other details that would have been difficult or impossible in OO9. Now a static model is one thing but you all probably want to see it move.


You'll probably notice two things from that video. Firstly the working lights are missing as I discovered that there was no way of routing the wires through the current print (another thing to add to the list of bits needing a redesign). Secondly the movement isn't very smooth. For some reason it looks as if they wheels are sticking during part of their revolution. It must be the wheels and not the layshaft as it's at the same point every time. You can see it more clearly in this video.


I've not figured out exactly what the problem is yet but I'm guessing that maybe one of the axles is slightly out of line leading to a tight spot. I'll try and investigate further but it may just be an issue with printing that will go away after some of the bits are redesigned anyway.

So not perfect, but I'm more than happy with my start in O14.