Routed Track Build

Routed Track Build

I am going to serialise the basic construction of a routed track from scratch, over the next however many newsletters it takes.
Instead of using some flash track from an expert, you get mine. Partly because I already documented it more-or-less anyway, so I get to cheat and re-use something I already have, but mainly because I am an "office boy" I was born with 10 thumbs, and failed "shop" at school. I learned by reading how others did it, and applying the most basic of self-taught carpentery skills from watching a friend who helped us renovate a couple of houses.
You get to see the mistakes, and the fixes. So, the idea is, if I could do it, so can you.


Anyway, here's Part 1.
I wanted a lightweight frame, to keep the weight managable for me to lift. I planned to have a system where the track could be stored on edge against one garage wall, so that we can still put the big cars away, and hopefully I can raise and lower it by myself. I worked out the dimensions for the top, which were 4.5 metres by 2.1 metres; being the largest size I could fit along the wall, and also the widest that I could reach to the middle from either side. I had also worked out the basic layout on paper, allowing for lane widths and "runout" for the tails to swing a bit on the outside of the corners. I made the frame just a little smaller in each direction. Not sure what you call this interlocking wood thing, but that's what I did. I cut all the runners for each direction as a group, to make life easier.

Once I had all the lengths cut, I cut a channel half depth along the length of the lengthways runners, then half depth cut on the runners for the cross direction.
I had worked out the spacings on grid paper first, so I knew what spacings to measure and cut . . "measure twice, cut once" they told me . . . I still made one mistake. No matter, cut in the right place, and glue and brace the weak area at the wrong "notch" later when the frame is assembled....
Put it all together like a jigsaw puzzle.

The reason the frame has those open sections at each corner, is because I will later cut rounded corners off the MDF top, so that hips don't take a whack all the time as people walk around the track.
Next up, I cut 3 "MDF sheet legs" Here I am test fitting them to be sure I got the dimensions right. The large radius cut out of the back of them is a pure 90 degree, and the entire track will later "roll" onto it's back edge using these as the 3 rollers. So that each edge will sit flush with the rear edge of the track. They stop 300mm shy of the front edge of the track, as there is sufficient support to tuck them away from getting kicked by feet standing at drivers stations. That, along with the oval holes cut out, serves to lighten the legs, and shift the weight balance of them towards the rear of the frame, lessening the eventual "dead lift" weight.

Finally for this stage, I test fitted these legs on hinges, with wood-arm braces to make them steady. The braces are secured by long bolts with wingnuts at the end, and can be removed easily when storing the track. The legs themselves are hinged, and simply fold flat for storage.
I then removed the legs, so the frame would later sit flat on the ground for fixing the MDF top.

Tech Section - Building a Routed Track Pt. 2
Picking up from last month

The cutout ovals in the legs, and having the legs stop 200mm from what will be the front of the track acheives a few things.
1) It keeps weight down
2) It moves the balance centre of leg the weight towards the back of the track, which moves the "tipping point" towards the rear
3) Having legs recessed back from the front will avoid having people inadvertantly clip them with their feet as they move about.

Then on to the marking out. Last time I just roughly marked and cut one lane, then used a pin guide to cut the other 2. That resulted in some unforseen tightness in one lane at a certain point, so this time I forced myself to be a bit more patient, and marked out the whole circuit including run-offs, keeping in mind the idea that I will have a direction flip switch for each lane, and be able to run it both directions. Therefore it needs to have wide "run-offs" for sliding cars, which work for travel in both directions.

At the right hand end there are two loops/u-turns. I cut two sheets of MDF in a sort of zig-zag shape right hand side, so that all the "U-turn" of track at each side of that end would be within a sheet, rather than it crossing over onto the other sheet. That just made it easier to keep the track surface flat and smooth, -and less joins to hold even. You can see the zig zag cut near the right hand end of the 1.2metre rule.


The layout lines don't show up too good on the pictures, so below is the layout as I originally did it using plastic track design software. 
I have 100mm lane centres except the squeeze at around 50mm in the hairpin which is top right, (ie, 100mm between the 2 outer lanes), for which the logic is giving centre lane the most grief, which might even up lap times, or at least make them more interesting and less predictable.

The main difference in the actual wood cut is that the underpass is moving outwards (upwards in this picture) as it runs to the right, getting closer to the track edge, and with that the esses are a little different. It also means that the underpass is in the middle of a straight, so that is it very seldom we will need to marshal under the bridge.


The tightest curve is the hairpin squeeze. Inside lane is 200mm radius 400mm diameter, middle is 500mm, outside is 600mm.
Wiidest curve is the outer one at left.
Curve diameters there are
1,450mm, 1,650mm and 1,850mm for the outside lane, so it will be possible to carry some nice speed around there.
I left most of the curves as fixed radius, with my logic being, that the people using it will do so just occasionally, or be not expert drivers, so I wanted to make it easier to learn and less technical than I would have if the same guys were to be racing on it week in and week out. Everything is a compromise.

I made up a thing they tell me is called a trammel or trammal, or camel, or something. I just thought it was a cunning plan for cutting constant radius curves. It looks like this. I thought I had become a genius, now I find people have been using these things to make curves since the pyramids.

and I used it like this

The result was surprisingly good, apart from a wee bit of "operator error" that will need filling.

I cut all the constant radius curves with it, and then cut the straights. Some of the straights stop short of the main curve, so that I can create a very gentle radiusing (is that a word), as a transition from one to the other.

For the odd joining bits,and the curves that aren't constant radius, I planned to use my trusty hose of a thousand nails like last time, but due to summer heat it was soft, and the router just dug into it, and the cuts turned to custard.

In the end I made my 3 zillionth trip to the hardware store, and bought a strip of aluminium, 20 mm high 1.6mm thick, 1.8 metres long and glued wood blocks on one side of it, so I could screw down to the track.
The cheap expoy I used didn't work very well, so back to the hardware store AGAIN for some better stuff, that cost me another day. @^%@&$% (dash and darn)

Then I found the wood blocks at 180mm centres were too far apart, and the strip would STILL flex when the router ran between the blocks. This meant more filling and sanding, and more muttering. In the end, I just banged in a 50mm brad half way between each block, and that made it work fine. You can see it at the top of the picture above, where it is set up to cut the esses leading into/out of the squeeze hairpin.

I put the side-cut bit into the router to cut the side-slot indents for the braid. It has a centre pin, which is 1/8th inch (3.2mm), that acts as a guide. I routed using a 3.2mm bit (generous 1/8th) instead of 3mm like last time, so that I could make use of this special bit for the braid depressions. I have since begun making these handy side-cut bits in 4 variants, as the nearest source was USA or Canada.

I fiddled a bit to get the depth right, then made a test cut to see how well it would track along the main slot, and how easy it would be to actually drive.
It went so well I cut a bit more, and a bit more. An hour later the whole track was done. I could not believe how easy cutting side slots for braid would be with it. One of my major concerns gone in an hour.

Tech Section - Building a Routed Track Pt. 3

Lifted the sections up onto the frame. Screwed down the non-elevated bits, pin tacked the rest a little, and tested the roll-against-wall for dead-lift weight [yep, I can do it easily], max 25kg as calculated. There's a bit of flex, owing the the fairly lightweight frame and overall dimensions, but it feels stable.

Started building elevations. Found that I can get some flex from the MDF (it's meant to be 9mm, but is closer to 10mm.) Pulled a 5 degree camber into the big sweeper and the rising turn at the other end of the front straight.

As you can see, I have filled a few errors, then re-routed. I used plaster to fill in places - DO NOT DO THIS
It doesn't set hard enough. Use builder's bog or similar, it sets as hard as the MDF then you can route again without fear of bits chipping do I know . . .  guess.

Now it's time to remove part of the top, and cut and fit the underpass. I didn't take any pics of this, but basicaly, I cut a piece a bit bigger than required in both dimensions, and laid it over the gap and tacked it both ends to hold it steady. I marked above the width it would be, and exactly where the slots must join with the main part of the track, then underneath I marked where the main track ends, and the undernath of the insert-tto-be could be seen. Then I cut it to size, and tacked down a bit of MDF offset from each slot by the width of the router base-plate and cut each slot individually. Miraculously - it all lines up for size and slots....

Insert for underpass done, and paint on. Now it's starting to feel like a track.

The paint looks all patchy in the photo due to random light relections, much better "in the flesh"

Next up, clear coat then paint the lane colours in the slots. THese shots are from my previous track. If you ar ebraiding, it doesn't matter whether the track or the slots are done first really, as any overlap is hidden under the braid-recess.
I do the slot painting as below pics.
Put paint into small squeeze bottles, so I can squirt it into the slots.
I get a bit of firm cardboard or strip of 2mm wide plastic, squirt a bead of paint into about half a metre of track, rub the card/sheet back and forth a couple of times . . repeat until done. 18 metres should only take around 30 minutes a lane, and there is very little over wash if you get into a decent rhythm.

In the pics below, I did red lane, then yellow, then finished with blue. - As you see, I got less messy as I went on. The whole thing took not much over an hour for 3 lanes, average 12 metres on my previous track.
Best part is, you get a liberal covering which soaks into the MDF and will stand up to years of guide-abuse.
As I had copper taped this first track, by doing my slots before I painted the main surface, any mess was covered by the tape or main track paint.
By the time I have painted the main surface, I also have enough paint onto the area under the braid/copper tape, that it is ready for laying the conductor.


Clear coat and lane colours done, braid laid - what a back-breaking task, 12 hours solid of braiding over 4 days, wired the driver stations as I went. Pretty simple just a 3 pin XLR plug, and a direction reversing switch. I now offer pre-wired driver stations for sale on the site!

Ready for cutting and painting and attaching the barriers now.

What surprises me most is the grip. I used the same paint and clear as on my first routed track, but seem to have more grip. I think I got the clear coat on smoother, with less "texture", so I am guessing tyres are locking in better. Most stock tyres work okay, and silicons have so much grip you can roll a car before the tyres let go.

From the south end

Tech Section - Building a Routed Track Pt. 4

The barriers are nearly all just 3mm MDF cut in strips to the width which gives the height I want. I went 50mm on the outside, for car safety, but 30mm on the inside which represents a wall approximately a metre high.
For the inside of the track I had previously routed an extra slot with my 3.2mm bit when I was routing the slots. The barrier on the inside of the track at the north end is simply press fitted into it. The outside barriers are screwed to the edges of the framing.
3mm MDF is quite flexible, and it is not difficult to bend it around a corner with a 200mm radius.
For the "wall between the upper and lower levels of track at the "north" end (left side in picture below), and centre of the track I had to estimate the height, and do a bit of fancy cutting and correction to fit it. There is only a token 15mm wall on the inside of the upper level sweeper turn, and in practice, I don't think a car has ever crashed and fallen from the top to the bottom.
I used a small amount of plastic fencing from my Ninco track on the rise up the hill, but I'd probably not do that again, it looks too artificial.

The track is running slightly faster lap times in one direction to the other - about 1 and 1/2 tenths naturally faster, but is easier to learn and be smooth driving, when running the other direction.

The scenery thing is still a bit of a challenge, and I'm probably going about it back to front, but I started with the things I KNEW I wanted in the finished artilce, and actually know how to do. So I made up a timing gantry, and the IR based timing bits, and got that working. It went pretty smooth. Apart from wiring the first sensor back to front, it worked straight away. The gantry was made from a couple of bits of old plastic curtain track top and bottom, with waste bits of clear plastic left over from making the router base and copper tape tool. Sprayed it up grey, and fitted the electronics, then covered over the front panel with a printed sheet for the track name and double sided tape.

Made up the trays for the cars to sit in under the main straight. Stores about 70 cars for easy access.
The trays go under this main straight at top of picture.

I made up and fitted the "street lights" to the base level of the circuit. I used "grain of wheat" bulbs inside 4mm aluminium tube I bent using a purpose bought "spring former" from our local model shop. Copying an idea from someone else on the forum, I used the heads of plastic teaspoons, cut and moulded, and glued on. Sprayed them with grey primer, which gives a matt, textured finished I liked, and coated the inside of each spoon head with aluminium cooking foil to distribute the heat and light down. Otherwise it shines through 8 coats of spray paint!

The amount of light from these is almost bang on, and they give a warm yellow glow, rather than being stark bright, again, the sort of effect I wanted.
I also lit up a model railway control tower I bought, I think it was "O"  or "G"scale, but near enough to 1:32 for effect. It was too high for the fold-away of the track, so I used it in 2 parts, and put a false roof on the lower level using a printed texture of old planks. Also put a layer of tinfoil underneath that to deflect the light down.

The lights are on 2 circuits, one for the street lights, one for the rest of the buildings, static vehicles etc. It iwll be easy to add a couple of heavy "pots" later if I want to be able to dim either circuit. Likewise, easy to add extra circuits if I want. The power to these is on illuminated switches, near one driver's station; so I can find the little beggars in the dark.

Put in a few road markings, and some tyre walls from Slot Scenics in the UK. Have roughly cut and fixed some wall filler foam in a couple of places ready for hills . . . all that and it seems like I've only just begun the scenery . . . . whew.

By day

And by night