Children's car tracks with electric cars

Electric motor

— usually, in this case, it means an electric motor installed directly in the car, although there are more specific options (like a mechanism with a pair of rotating rollers installed on the track and giving a pulse to the car every time it passes through it). Note that the built-in electric motor is often powered not by batteries, but by a supercapacitor, and before starting to move, the car must be installed on a charger in order to accumulate energy in the supercapacitor.