How to make your own electric train

This activity is part of our Science Lab series. Check out the ANU Science Lab for more experiments! In this activity, you will build a DIY electric train using a battery, neodymium magnets, and a copper coil to explore magnetic fields, electromagnetism, and linear propulsion. Watch the video above to see how it is done.

DIY electric train materials & ingredients

For this activity:

• 1 AA or AAA battery
• 4 strong neodymium disc magnets or 2 rare earth sphere magnets (slightly larger in diameter than the battery)
• Copper wire
• A cylindrical object (such as a marker, pipe, wooden spoon handle or dowel to wind the wire around)

Safety Note: Strong magnets can pinch fingers - be careful when handling.

How to make a DIY electric train: Step-by-step instructions

Step 1: Create the copper wire track

1. Wrap your bare copper wire tightly and uniformly around a pipe to create a long, spring-like coil. The coil should be slightly larger than the battery and magnet diameter, but not too much bigger.
2. Ensure the coils sit close together without touching too tightly, then slide the finished copper tunnel off the tube.

Step 2: Prepare the train engine

1. Attach two neodymium magnets to the positive (+) terminal of your battery and two magnets to the negative (-) terminal. Or just 1 magnet to each end if using the sphere magnets.
2. Ensure the outer poles of the magnets oppose each other so that both ends have matching magnetic polarities pointing outwards.

Step 3: Launch your train

1. Insert your battery train assembly into one end of the copper coil tunnel.
2. Watch as magnetic forces pull the train into the coil and push it through to the other side! If it repels, simply flip the battery train around.

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How a DIY electric train works: The science explained

This simple setup functions as a linear homopolar motor, demonstrating how electric currents and magnetic fields interact to create movement:

• Creating an electromagnet: When the conducting neodymium magnets touch the copper wire, they complete a circuit. Electric current flows from the battery through the magnets and into the section of copper coil surrounding the battery, converting that segment of wire into an electromagnet.
• Magnetic attraction and repulsion: The electromagnetic field generated by the coil interacts directly with the permanent magnetic fields of the neodymium magnets on either end of the battery.
• Propulsion force: By orienting the neodymium magnets correctly, the magnet at the front is pulled forward by magnetic attraction, while the magnet at the back is pushed forward by magnetic repulsion. This dual push-pull force drives the train continuously through the copper tube.

Science fair projects & taking it further: Experimenting with variables

• Coil tightness: Test how the spacing of the copper loops affects train speed. Does a tightly wound coil push the train faster than a loosely stretched one?
• Coil loops and tracks: Connect multiple copper coils together to build a longer track, incline, or full circuit loop to test how far your train can travel.

Enjoyed this experiment? Explore more hands-on activities on the Science Lab ANU YouTube channel.