What is meant by "balustrade" in escalator design?

In escalator design, the term "balustrade" refers to the enclosing structure along the sides of the escalator that contains handrails. This component is vital for passenger safety and accessibility, providing support and stability as individuals use the escalator. The presence of handrails allows passengers to maintain balance and grip while ascending or descending, thereby reducing the risk of accidents.

The balustrade also serves an important aesthetic function, as it can be designed in various styles to complement the environment in which the escalator is installed. Its structural design ensures that it can withstand the forces exerted during use, highlighting the importance of safety standards in escalator design. The other options refer to components that play different roles in the overall function and operation of the escalator, but none align with the specific definition of "balustrade."