Which of the batteries do you think will be the fastest ? You can be very surprised at the result. If you like trains, then the simple electric train will be very enjoyable for you .The electromagnetic track is very fun. you need these three parts to making the track. 1. copper wire raw 2. battery ( AAA, AA or C ) 3. and two neodymium magnets ( it must be larger in diameter than battery ) If you have all the components so fun can start.