Regardless of how simple or complex the model train layout is, all model train operation follows one basic principle. The train speed and direction is controlled by varying the voltage and polarity of the electricity reaching the motor.

Electrical currents are not the same in every country. It is important to know what voltage system operates. A local electricity supplier, or a local electrical contractor can supply the required voltage information. The high voltage circuit in the wall socket can cause injury or death. Also, it pays to carefully read any safety instructions that are included with most train sets before getting started.