How to Build a Tiny Cardboard Train That Actually Works!

Cardboard is a versatile, lightweight, and easy-to-work-with material, perfect for creating all kinds of creative projects.

In this instructable, I will guide you step by step to build a fully functional miniature train using cardboard and glue.

The best part of this project is that the entire set is approximately the size of a CD case, making it ideal for display in small spaces or as a unique decorative piece.

Additionally, this is an excellent way to exploring basic principles of mechanics and design (no need for electronics or batteries 😉)

You will need a bit of patience and creativity to bring your own tiny train to life that actually moves.

Let’s get started and make this train come to life on its tracks! 🚂✨(here link video)

Supplies:

1. Gray cardboard sheet 3 mm.
2. Gray cardboard sheet 1,5 mm.
3. White cardboard 0,5 mm.
4. 6 (six) neodymium magnets Ø5 mm x 1 mm thickness (*)
5. 6 (six) neodymium magnets Ø3 mm x 1,5 mm thickness (*)
6. Wooden dowel Ø6 mm.
7. Super Glue.
8. White Glue.

(*) You'll need to zoom in on the photo to see the magnets, as they're very small compared to the rest of the materials and tools ( Check the bottom left corner)

Tools:

1. Metallic ruller.
2. Pencil.
3. knife pen (cutter) or Scissor.
4. Cutting mats green (or similar).
5. Laser cutter (or access to laser cutting services)
6. A3 color printer + A3 sheet self-adhesive paper or access to one (recommended).
7. Wax (or candle).
8. Cotton rag.
9. Embossing tool (metallic/plastic circular ball diameter 1,5 or 2 mm).

The modern globalized and hyperconnected world allows us to discover the work of incredible artists across numerous disciplines. This instructable was inspired by Brad Litwin's work: "MechaniCards Desktop Kinetic Sculpture."

As a true fan of the well-known ROKR puzzles myself, I drew additional inspiration from their traditional mortise-and-tenon joint system.

This miniature automaton replicates the operation of a tiny train: a locomotive and two wagons that travel in a circular motion.

I used only cardboard and printed self-adhesive paper for the design of an automaton that operates through the movement of a crank. This crank drives a pair of gears, which, with the help of neodymium magnets, simulates the circular motion of the tiny train completing its circular track.

The dimensions match those of old Compact Disc cases: 152 x 145 mm.

The entire set is stored inside a sliding drawer cardboard box 40 mm in height.

For the design, I used the following software:

1. Geargenerator (for the gear design)
2. Autodesk fusion 360 (for the complete 3D design of the set)
3. Lightburn (for prepare parts and export the files for laser cutting)
4. Adobe Ilustrator (for design the colored self-adhesive parts attached to the cardboard)
5. Pacdora (for the design of the cardboard box that covers the set)

I used my CREALITY FALCON 2 (22W) laser cutter.

If you don't have one, don't worry, you can request the cutting service at a local shop that offers it.

The first step is to cut the cardboard sheets using a utility knife (or box cutter) or scissors, marking the measurements in advance with a metal ruler and pencil:

1. Gray cardboard 3mm: Cut a rectangle of H=350mm x W=250mm.
2. Gray cardboard 1.5mm: Cut a rectangle of H=250mm x W=250mm.
3. White cardboard 0.5mm: Cut a rectangle of H=400mm x W=250mm for the sliding drawer, and another rectangle of 400mm x 400mm for the box body.

Laser cutting parameters:

1. Gray cardboard 3mm: Cutting layers at a speed of 500mm/min - Power 80%.
2. Gray cardboard 1.5mm: Cutting layers at a speed of 700mm/min - Power 50%.
3. White cardboard 0.5mm: Cutting layers at a speed of 1000mm/min - Power 30%.

I've attached here the LightBurn's files to download and use for laser cutting. And here the svg files.

💡You can adjust the speeds and parameters according to your laser machine or your preferences and usual practices.

Once the pieces are cut with the laser machine, you will see that each one is labeled with an identification (a letter followed by a number).

For assembly, follow the explanations included in the attached sheets (they are all self-explanatory). In addition to that, I’ve included some illustrative random photos and two videos showing the test runs that should be done at different stages of the model.

Carefully remove each piece as you progress with assembling the set.

You can do it in most cases with your hands or with the help of an embossing tool (metallic/plastic circular ball with a diameter of 1.5 or 2 mm).

In my design in LightBurn, I added tabs: to remove small pieces, first cut the tabs with a utility knife.

If you find any excess material or edges, remove them with cutter or with sandpaper.

Clean the excess charcoal from the sides of each piece.

Before applying glue, double-check that you are not making any assembly errors.

Keep in mind that if you make a mistake, separating the parts will be very difficult with cardboard, as it could damage the pieces.

On the 3 mm, 1.5 m cardboard sheets, you’ll notice there are extra pieces for some positions—especially the smaller ones—in case any break or if you make a mistake while gluing. These are spares.

I recommend using small portions of glue when adhering the parts.

Below is a step-by-step detailed explanation with images:

1. The instructions include symbols indicating when parts need to be glued or when wax should be applied to lubricate rotating components (See photos).
2. Each image displays the part numbers in the top left corner. Letter A refers to all 3 mm parts, and B to the 1.5 mm parts.
3. 💡Before starting the assembly, take a quick look at 100% of the explanatory sheets.

1) Start by assembling the gearbox. Take the 3 mm base (part A1), build the shafts for two gears, and glue them onto the base.

2) Assemble the sides of the gearbox using the mortise joint system. The tightness of the fit will depend on the "kerf" setting you use according to your laser cutting machine. If you choose the right parameter, glue may not be necessary to join all the parts.

3) Glue two washers in place over the gear shafts.

4) Assemble the largest gear, which will hold six 5 mm diameter neodymium magnets, and place it onto its shaft.

5) Assemble the smaller gear, which will house the crank-arm system, and place it onto its shaft.

6) Assemble the crank-arm system.

7) Place the crank-arm system into the cross-shaped hole of the smaller gear and perform the first functionality test. Check out the animated GIF at the top of this step or or view here in youtube—you’ll see the gearbox starting to run! 😀

8) Once the previous steps are completed, close the gearbox with the 1.5 mm thick cardboard cover. A die-cut self-adhesive sheet with the train track design, etc., will be glued on top of this cover later. Since we are still in the testing phase, do not glue the cover yet—just make sure it is properly positioned.

9) Assemble a box around the area of the smaller gear.

10) Perform a second functionality test of the assembly.

Check out the animated GIF at the top of this step to see the gearbox assembly fully running with its cover on, or view here in youtube.

Follow the same instructions as in the previous step, but pay special attention to working with even smaller pieces.

In this part, you will need to sharpen your patience to work with very tiny pieces. Once assembled, you can proudly say that you built a locomotive just 1 cm long 😎

1) Assembling the locomotive (train engine):

2) Assembling the train cars:

We need to assemble 2 (two) identical train cars.

3) Assembling the train station building:

Take all the pieces indicated in the image and carefully glue them in the order that seems most appropriate based on the final model.

Now comes one of my favorite parts: applying the printed, satin-finish, self-adhesive paper (see here on youtube).

It's already die-cut to make it easier to place on the gearbox cover, the train, and the train station building.

References:

stickers C1,C16,C17 to be applied to gearbox.

stickers C2,C3,C4,C5,C6,C7,C8,C9 to be applied to train station building.

stickers C10,C11,C12,C13,C14,C15 to be applied to train and train cars.

In this step, I’ve attached the Adobe Illustrator file so you can print it at a specialized shop, or by yourself if you have a printer and cutting machine combo.

Suggested application method: remove the backing and carefully position the sheet at one end of the surface to be covered.

Slowly apply it, making sure to avoid air bubbles and wrinkles.

Once applied, use a cloth to ensure a smooth adhesion.

In my case, I also used a rubber roller, pressing firmly.

Starting with 0.5mm white cardboard, which we die-cut using the laser cutting machine, you will see how to assemble it next.

First of all proceed to mark the lines that require folds (see diagrams with red lines). You can do this using a ruler and the help of an object that allows you to apply pressure on the white cardboard.

To build the sliding drawer box that protects the whole project, simply follow the short video tutorial provided GIF above or here youtube.

Use glue only when necessary.

Before starting this step, carefully check the polarity of the neodymium magnets Ø5 mm and Ø3 mm.

Placement on the large gear: Place the largest gear on a flat surface and position the Ø5 mm neodymium magnets in each of the holes. Use a punch to press until the magnet reaches the stop and is flush with one of the surfaces.

Placement on the train: On the bottom of each part of the train (locomotive and wagons), there are pre-designed holes to place the Ø3 mm neodymium magnets. In this case, also use a small amount of glue to ensure fixation.

💡 All hole measurements are designed to allow the magnet to be held in place by pressure on the cardboard. However, secure with a small amount of glue. And only do this when you are completely sure of the polarities, because once glued it will be impossible to change them due to the very small size of the pieces.

Given the small dimensions and low weight of the assembly, I experimented with several ideas to solve the mechanism.

I eventually chose a traditional shaft-driven system, where the shaft drives a small gear.

At the end of this gear, there's an arm with an eyelet that allows for the vertical insertion of a lightweight wooden handle made from a 6 mm diameter dowel.

To build the handle, cut the dowel to approximately 10 cm in length and sand down the final centimeter of the tip, reducing its diameter to 4 mm. This way, it can fit into the arm’s eyelet.

Place the train station building in a location similar to the one in the figure or wherever you prefer (I decided to glue the handle instead of leaving it removable). Here link video.

Position the locomotive and wagons in the same relative position where the magnets of the gear wheel are located.

Turn the set with the crank and enjoy watching the train come to life and operate!

Once you see that everything is functioning smoothly, permanently glue the upper lid gently.

Take the gearbox with your hands and insert it into the lower interior of the sliding white cardboard drawer (see photo).

Your work is finished, congratulations!🎉 (here link video)

Let the imaginary passengers hop on the train, crank the connecting rod, and enjoy watching the train and wagons go around the tracks...

....................

I hope you enjoyed it like I did. 😊

If you have any question ask them in the comments below!

I would also love to hear what you think about the project.

Happy making!

cfb70 - Instagram @cfb70ok

PS: If you want to see my other works on instructables look here:

https://www.instructables.com/member/cfb70/instructables