What indicates the points at which coasting is required under normal conditions for train operators?

The correct answer highlights the importance of signs along the route, which are specifically designed to inform train operators of critical information, including where coasting is required under normal conditions. These signs serve as visual cues that indicate to operators when to reduce speed or allow the train to coast without applying power. This practice is essential for maintaining control of the train when transitioning between stations or approaching areas where speed restrictions are necessary.

Signs are standardized and placed in key locations along the route, ensuring that all operators are aware of the required actions without needing real-time instructions or additional communication from outside sources. This leads to a more consistent and safe operation of trains across different runs and conditions, as operators can rely on the established markers that have been put in place based on prior assessments of the track and operational needs.