A gear train is a mechanical system that consists of two or more gears working together to transmit motion and force. Gears are circular objects with teeth that interlock, allowing them to transfer rotational energy from one gear to another. This system is commonly used in various machines, such as clocks, vehicles, and industrial equipment, to control speed and torque. The arrangement of gears in a gear train can vary, affecting the output speed and direction of rotation. For example, when a smaller gear, known as a pinion, drives a larger gear, it increases torque while reducing speed. Conversely, a larger gear driving a smaller one will increase speed but reduce torque.