Pneumatic systems use vacuum technology to move the elevator cab between floors. Turbines at the top of the elevator shaft draw air out of the tube, and this causes the cab to be pulled upward. When the cab reaches the designated level, steel brakes secure it at the landing. When the cab goes down, the turbines turn on briefly to lift the cab off the brakes. Once the turbine shuts off, the cab drifts slowly and quietly to the desired floor, where the brakes will engage once again. For more appli