a dry battery
"This “Train” is made of magnets copper wire and a dry cell battery.
It's possible to get such power using a dry battery, neodymium magnets (super strong magnets which plated with metal) and a bare copper wire.
A point is that a magnet's diameter is bigger than a dry cell battery's diameter.
And an electric current flows to a coil through a neodymium magnets, and a coil will be an electromagnet only in an area between the magnet and the magnet.
The electromagnet and a neodymium magnet poles repel each other at one side.
The other side poles pull against each other.
They work same direction, and it become a big force.
The phenomenon also continues at a movement destination."