The Great Outdoor Duplo Train Track - Made From Pallets

I used to work at LEGO, as a Technology Scout. Before I joined, I wondered why you don't often see LEGO advertised being used outdoors. It turns out, there are many good reasons why the company does not advise getting your bricks dirty outdoors: Firstly they can be fiddly to clean. Secondly, if left outside for days at a time in bright sunlight, this will make the plastic brittle (UV rays damage many plastics). So this instructables is not 'the done thing', but as a enthusiastic dad, I realised my son was wanting new challenges with his Duplo set, and so I wanted to 'blur the lines' of where the play indoors ended - and building larger projects outdoors began! Safe to say you can bring the Plastic Train and Coaches back indoors (to avoid UV degradation and dirt), and leave the wooden tracks outside. So this seems a fair compromise of extending the play of Duplo to be more 'advanced' for your kids, whilst not damaging the plastic.

I've written a good number of Instructables, and I would say I allow my son to use technically adult tools like drills, under heavy supervision (example). Safe to say, please only do this if you feel totally confident that you're happy to assess and accept the risk as a parent or guardian. I cannot accept any responsibility for any injury.

With that legal bit over, if you do elect to have a go at this - it is huge fun, and really allows for some interesting 'mash-ups' of the very precise and predictable world of your Train riding on plastic Duplo (little goes wrong as everything has been pre-validated), whereas the home-made wooden tracks throw up all manner of curve-balls, perfect for the inquisitive and problem solving mind! I've written content for companies like the Design & Technology Association UK (link) and Primary Engineer (link), and consistently the emphasis has been to equip kids with problem solving skills, and to be comfortable with 'failure' as part of the process of incremental innovation (and life!).

Indeed, if you've read any of my other projects (also on IG), they are part DIY, and part Philosophical Musing on what parenting can be, if we accept a little risk, and a bit of unpredictability. Certainly, this project didn't 'go right' first time, and my son and I spent considerable time sanding, sawing, drilling, adjusting, etc. - all to 'debug' and 'fine-tune' the build. Often a slope was too steep, or the transition between one ramp and another caused the train to 'beach' itself and get stuck, or it might detail of a twig obstructed it's way. Splinters happened, (but less than you think). Thumbs got hit with hammers, but there were no tears. There were many 'crashes' of the train - much the amusement of my son!

All in all, it seems that the fallibility of the project (and perhaps of me attempting it) was the most valuable thing to my son. To persist and explore together. To continually be problem solving and testing. Learning to learn. We had a great time - I hope you do too. Be safe, take your time, and build cool projects - and fond memories!

~

A Surprise TV appearance.

This train track design was originally devised as part of a Heath Robinson (aka Rube Goldberg) 'machine', as part of Sir David Jason's Great British Inventions, on Channel 4, UK. Scroll to the end if curious to see the final contraption in action, which was made in 2 days, and closed the 4-part series. That in turn inspired me to make this in our garden, as I was rather pleased at how well the wooden tracks worked out! I had also borrowed my son's train, so after a week away for filming, it was a nice way to thank him for his contribution to TV.

Pallets - I suspect you're familiar with sourcing pallets (being on Instructables). But if not, do check out some previous work (link) - which goes into details about how to get nice ones (not all pallets are created equal or clean/safe to use!).

Plywood - For the corners, you want to avoid wood with a 'single grain direction', so Plywood solves thsi problem. I used 12.5mm (1/2inch) Marine Ply.

Edge Cutting - I used a mini-router or 'Laminate Trimmer' (link). I should point out - I did not use this with my son around, as it's very noisy (wear ear defenders) and operates a very high speed, so in a blink of an eye, it'll do a lot of damage, in an accident. You could use a circular saw to do similar cuts in planks of pallets if you don't have a Router.

Clamps - Essential to keep the wood in place and avoid needing to hold with your hand. 'Quick Grip' clamps are cheap and very useful beyond just this project. (link). If you have a workbench (link) do also use that.

PPE - As mentioned the router is very high speed, so goggles are essential. Ear Defenders are highly recommended. There are two schools of thought on whether you should use gloves - I'd personally don't as this can risk you becoming 'tangled' and pulled into the blades, cutting / breaking bones. I suggest following any safety instructions with said tools if not sure. I highly recommend getting kids goggles also! (link) - I've written more about kids and tools here (link) if interested.

General Cutting - I've used a Circular Saw (link) for cutting straight cuts.

Wood Stain - I used Fence Paint/Stain, which is water based, and non-toxic (link). Although not 'recommended for kids', it all washed off in the bath!

Duplo Train - Classic (shown here), and updated fancy techy one (here). I'd say the new one is much cheaper - and has some fun elements you could play around with, using coloured 'Action Bricks'! (link).

I allowed my son to use a 'Stubby Hammer' (link) - although levering the nails out of the pallets is tricky. It should also be said, pallets do contain nails which may protrude. Rusty nails can be a Tetanus risk, so do be careful. I tended to 'pre-check' everything before allowing my son to have a go.

You may also find a 'Nail Punch (link) useful to drive in any nails which cannot be pulled out.

I used a scrap of card to allow me to set up the saw as shown, so it was 52mm wide.

I suggest you may want to use a workbench/clamp for safety.

The goal here is to have the overall width of the 'planks' being 54mm, with a raised section in the middle 32mm wide - so the 'cuts' either side were ~11mm each side (done by the router), and about 5.5-6.0mm deep.

Bear in mind that tools and wood will have inaccuracy, so better to start off a bit 'generous' (and remove more material), and then dial-in the best setting to fit. The Router may be placed 5.24mm deep, but actually ends up cutting less or more, depending on a variety of factors (including your way with the tools)...so take your time and proceed with care.

After much routing noise, and sawdust piles (also good for 'treasure hunts' by marking trails in the forest), I had a good number of straight 'tracks' made. Test that the Duplo Train works nicely on them.

Note - too deep, and the train 'beaches' and does not move / wheels spin. Too shallow, and any wobble or bump, and the train jumps the track. So the goal is to get it close to the Duplo size as possible...LEGO has evidently 'fine tuned' this, so best to follow their lead!

This is indeed the tricky bit! However, the main thing is to trust that the routing tool is intended for 'profiling', so a gradual corner is what it's made for!

Begin by marking out a '90 degree' turn (three pieces of bent track), cutting this out of Plywood. Clamp in place on a table or bench. Then using the guide, route the outside and then inside edge as shown. Sorry I didn't take any photos of this step, but you get the idea.

Any rough edges or missed bits, you can 'tidy up' with a hand rotary tool.

Test it can go round in a circle, as shown!

This is where my son could really participate again, as we made the various 'levels' of the track at different heights. The elevations were made from 1.5x1.5inch lengths of wood we found in a skip, and were cut to height, and a point cut to allow it to be hammered into the ground.

Upon this, the tracks could be fixed. I suggest if you use small 'blocks' like this, you may want to add a intermediary piece to join two planks (straight-straight or straight-bent or bent-bent) together with screws. I suggest screws (not nails) as you may change your mind and want to reposition - we did often! (Part of the fun, arguably).

As shown, my son agrees one should 'pilot' a hole before inserting a wood screw. This is to avoid the wood splitting.

Again, any splinters - remove with a scalpel or rotary tool.

Measure Twice; Cut Once - as they say, so we checked how this would look around our garden plants, before we hammered in stakes and screwed things in place.

This was a lot of fun, and even though some cutting is needed, it's quite a fast an iterative process of 'design and fit' with the various pieces of wood now.

This is a great way to learn about 'real world physics' - test and retest.

I look back at my childhood and lot of the 'learning' was 'trail and error', with these sorts of open-ended tasks. As you can see, it's a dry day, so the train wheels have a particular friction [coefficient] with the wood. This may change with age, humidity, debris - who knows! So I'd suggest finding the 'absolute max angle' you can drive up (it's more than you think!), and then reduce that by say 25%.

Also consider how many carriages you want to pull up said hill... we agreed on just one.

Interestingly, when going down hill - the speed is fast, so you need to consider this if covering immediately at the bottom, as we did.

Much of what schools teach may give the impression of being more 'advanced' than this, with F = μN equations, but frankly, nothing beats getting a 'hands on' feel for when something looks right, and no textbook will teach you that. If you are a kid who's wanting to get into design/engineering (or a parent) - this is what often differentiates people in the workplace - it starts as 'childsplay' but ultimately evolves into 'tacit knowledge' and whether you're Lovelace or Babbage, you need to visualise not just the idea, but the idea working in reality. Anyway, rant over for now!

As mentioned before, a lot of refinement is required when working with natural materials, which will throw-up unpredictable elements like splinters, knots, warps, and will need filing-down, bending back into position, and more.

As much as LEGO is a great tool/toy - it perhaps can be 'too perfect' sometimes, and that can end up being its own limitation, as kids need to build a resilience to know that most things in life don't 'click together like LEGO' and need tweaking and fiddling around with to get right.

We perhaps spent 2 hours actually building, and 2 hours (collectively) on preparing / debugging / fine-turning. One of the nice aspects was watching it go wrong - and then getting my son to speculate as to why... that led to us sometimes following his idea, only to realise it failed again, and again - but over time - we fixed it. I wonder why schools do not really have this methodology as much these days. So much of life is dogged persistence, rather than a quick win.

There is a nice 'closure' or 'crescendo' to work, which I'd not fully appreciated until being a parent - painting often represents both the 'we did it' - and also an anticipation to play with it the next day. Luckily we did this in summer, so it was dry in about 1 hour (after dinner) so he got to play before bedtime!

Arguably gloves would have been better, in hindsight but all washed out okay.

The small camera used was a 'Spy Cam', and is useful for video, even if sound is pretty terrible. (for example: link)

Hope you enjoy it!

Jude

https://www.judepullen.com/

https://www.linkedin.com/in/judepullen/

https://www.instructables.com/member/Hey%20Jude/instructables/

I feel very lucky to have worked with Sir David Jason on this TV show, staring alongside him, as his 'workshop assistant' - as we build various historic prototypes of Great British Inventions, using modern-day items - e.g. making a Lightbulb from a jam jar and mechanical pencil 'leads' (graphite), and a replica of the Bell Telephone using plumbing supplies and kitchen utensils. Do go watch the show! (link).

To round off the series, I was asked to make a Heath Robinson Contraption (Robinson's (English) work predated Rube Goldberg's work (American) - although Rube arguably took it to a wider global appeal!). This was done in 2 very long days, and we had two takes only to get it right - amazingly it worked first take! If you've ever done anything like this - that's a very high expectation on what is notoriously unpredictable.

As part of this crazy sequence, this is were I devised the train track 'hack', using wood, as it was cheaper and more efficient than buying a lot of plastic tracks and screwing them to wood. So with the help of farmer Richard, who owned the lovely rural barn used for filing, we built about 7m of track in the roof beams!

Hope you enjoy the video, but to break it down, some of the stills may help...

1. David lights the candle, and sets the water to boil on the portable kettle/stove to bre the tea he later drinks.
2. The candle is placed near the hemp string, which burns, and released a weight which pushed down on a plunger.
3. This plunger is a nod to the hydraulics which power the JCB digger. The plunger pulls some string to switch on the light (Joseph Swan who also invented the lightbulb at the same time as Edison - link).
4. The digger tips over a heavy spanner, which flips the Phone (Scottish), into a Rugby Ball (English).
5. This starts the Bike (English) rolling, which spins the globe, with the Wright Brother's plane (Americans) - but this has a moving story of how Percy Pilcher would have been the first (English) person to fly a powered plane (link).
6. The train is of course tribute to Stephenson's Rocket (link)...(English - you get the idea!).
7. The train passes by a Chandelier, which is a in-joke to Del Boy's mishap in Only Fools and Horses.
8. The Tennis (English) ball then is 'replaced' by a Cricket (English) ball, before triggering a Tank.
9. Books fall over, around a Davey Lamp.
10. Finally a heavy pully is released to pull the kettle, which then pours water into the teapot, which then pours tea into the teacup, which Sir David - committed to the role! - drank some of, despite being about 2 days old (sorry, Sir David! We thought you'd mime it).

Anyway, for any young inventors out there on Instructables, I'd highly recommend doing some prop making for TV. I've written about this a little more (here), and spoken about BBC Big Life Fix also (here). Wise Owl Films were just amazing to work with - and many thanks to the team there also!

Anyway - enjoy the show! https://www.channel4.com/programmes/david-jasons-great-british-inventions

Many thanks again to Richard, who was there with me at the crack of dawn, to late at night, offering suggestions, and helping me not injure myself whilst up a step ladder! Richard was technically not 'TV crew', but just helped out, and I wouldn't have done it without him. Thanks Richard!