The document discusses the components that make up the control system of an escalator. It begins by providing background information on escalators generally, including that each stair contains wheels that run on two rails and how the rails are configured at the top and bottom to allow for easier boarding and disembarking. It then describes some key components of an escalator's control system, including the floor plate passengers stand on, the comb plate that connects the stationary floor to the moving steps, and the truss, which is the hollow metal structure bridging the upper and lower landings and carrying the track sections.