What is defined as a mechanical device used to guide trains from one track to another?

A rail switch is a mechanical device designed to guide trains from one track to another. It consists of movable tracks that can be positioned to allow a train to easily divert from its current path onto a different track. This is crucial for managing train movements, enabling trains to change directions or routes safely and effectively. The functionality of the rail switch is vital in rail operations, particularly at junctions and stations where multiple tracks converge.

In contrast, a crossover track involves two rail switches positioned near each other, allowing trains to move from one track to another. A signal box is used to control railway signals and ensure safe train operations, but it does not have the mechanical function of guiding trains. A track junction refers to the point where two tracks meet but does not specify the mechanism used to guide trains between them. Thus, the emphasis on the mechanical nature and specific function of the rail switch clarifies why it is the correct choice in this context.