Engineering Excellence - Crank-Operated Cart

This design (at the top of the folio) shows how to transmit motion to the axle of a wagon. When the crank is turned, the toothed wheel moves and engages a sprocket. This drives the axle which turns the wheel.
Motion is transmitted to only one of the wheels so that the other wheel can move at a different speed when the wagon is turning.
A car differential fulfils the same function today.