ClipArt ETC
"A combination of wheels and axles, as shown, is called a train. The wheel in a train to which motion is imparted from a wheel on another shaft by such means as a belt or gearing, is called the driven wheel or follower; the hweel that imparts the motion is called the driver." —Hallock 1905

Train

"A combination of wheels and axles, as shown, is called a train. The wheel in a train to which motion…