What is the name of a track that is designated by timetable upon which movements are authorized?

The correct answer is the Main Track. This term is specifically defined within railroad operations and is intended to indicate a track where movements are authorized entirely based on the timetable. It is the primary track for train movements and usually allows for the operation of trains in both directions unless otherwise specified by operational controls or signals.

Main Tracks are essential for ensuring the safety and efficiency of train operations, as they require careful scheduling and adherence to operational rules. This designation also implies that trains have the right of way and that all movements, including those of subordinates, must yield to trains on the Main Track.

In contrast, Secondary Track, Branch Track, and Auxiliary Track are terms that refer to other types of tracks that generally have different operational purposes, such as serving as sidings or for specific service functions, and do not have the same level of authority for movements as a Main Track does. Understanding these distinctions is crucial for safe railway operation and navigation of the rail network.