What type of signals are defined as being controlled by time factors?

Grade Time Signals are defined as being controlled by time factors, which means they are typically used to manage the timing of train movements at specific locations such as grade crossings or station stops. These signals help to ensure that trains are appropriately timed to maintain safety and efficiency, especially in areas where tracks might converge or where there are potential hazards.

For instance, Grade Time Signals often operate based on predetermined intervals to either prevent collisions or to allow for the safe passage of trains through junctions or crossing points. The timing aspect of these signals is crucial, as it regulates not only the train schedules but also the interactions with other traffic, providing a systematic way to manage train flows through complex areas.

Marker Signals, Approach Signals, and Dwarf Signals do not primarily focus on the timing control aspect, which clearly sets Grade Time Signals apart in this context.