Which track holds a moveable curtain that can serve to hide the stage or function as a backdrop?

The moveable curtain that serves to hide the stage or function as a backdrop is associated with the tab track. In theatrical settings, tab tracks allow curtains to move horizontally across the stage, enabling the configuration for varied scenes and transitions. This movement can effectively reveal or conceal the action taking place on stage, making the tab track an essential component in stage design for managing visibility and enhancing the storytelling experience.

By contrast, other options serve different functions: a wipe typically refers to a technique in lighting or video transitions rather than curtain movement; a traverse track is similar but is more specific to curtains that travel along the line, often seen in modern staging but not defined solely by its ability to hide or reveal the stage; and a thunder sheet is a sound effect device rather than a curtain mechanism. This understanding emphasizes the role of the tab track in creating dynamic visual environments in theater.