gear train

is a set or system of gears arranged to transfer rotational torque from one part of a mechanical system to another.

Gear trains consists of:

• Driving gears - attached to the input shaft

• Driven gears - attached to the output shaft

• Idler gears - interposed between the driving and driven gear in order to maintain the direction of the output shaft the same as the input shaft or to increase the distance between the drive and driven gears. A compound gear train refers to two or more gears used to transmit motion.