What type of cover is fastened to the header to prevent dirt from accumulating on the door tracks?

The type of cover that is fastened to the header to prevent dirt from accumulating on the door tracks is referred to as a hanger. This component plays a crucial role in the overall functionality of the elevator door system. By providing a barrier, it helps maintain cleanliness and reduces the likelihood of debris interfering with the door's operation.

Hangers are designed to fit snugly at the top of the door frame and work in conjunction with the door tracks, ensuring smooth movement and preventing the accumulation of dust and dirt that can lead to malfunction or increased wear over time. Proper installation and maintenance of the hanger cover are essential in preserving the longevity of the elevator door system.

In this context, while protective, casing, and shield might suggest some form of coverage or safety, they do not specifically refer to the component that is primarily responsible for keeping the door tracks clean. The term "hanger" accurately identifies the function of this cover in an elevator system.