Which component is essential for the movement of the escalator's step?

The step chain is critical for the movement of an escalator's step because it is the component responsible for connecting the individual steps to the escalator's drive mechanism. When the escalator is in operation, the motor turns the drive wheel, which engages the step chain. As the step chain moves, it pulls the steps along the stair tracks, enabling the escalator to transport passengers smoothly between different levels.

Each step is linked to the step chain, allowing for synchronized movement and ensuring that they maintain a consistent pitch and alignment as they travel up or down. This mechanism is vital for safety and efficiency, as it guarantees that passengers can walk on a stable, flat surface without interruption. Understanding the role of the step chain highlights its importance in the overall functionality of the escalator compared to components like the handrail, which, while important for passenger support, does not contribute to the step movement itself.