The ground wheel and the axle of the Ferris wheel were connected to each other by a massive chain that wrapped around them both. The ground wheel and the axle both had a band of raised pieces around them, called sprockets. The links of the chain fit over the sprockets and held the chain in place. As the steam from the boilers forced the ground wheel to rotate, the chain was pulled along the sprockets. This caused the axle above to rotate as well. The axle then turned the Ferris wheel. A series of brakes and other control devices regulated the energy input to keep the wheel's movement smooth and steady.