What does a Switch Point Indicator do?

A Switch Point Indicator plays a vital role in railway safety and operations by showing that switch points fit properly during movement. When a switch is properly aligned and secured in the position for the intended track, the indicator provides a visual confirmation to the train crew that it is safe to proceed. This helps prevent derailments caused by misaligned switches, ensuring that trains can transition smoothly from one track to another without encountering obstacles or discrepancies.

The other options focus on aspects unrelated to the primary function of the Switch Point Indicator. For instance, while speed limits and types of trains might be relevant in a broader operational context, they are covered by different signals and signage on the railway system. Similarly, signaling the train's arrival time is handled by other tracking and timing systems, not the Switch Point Indicator. Thus, focusing on its primary function of verifying the fit of the switch points during movement underscores its critical role in maintaining safe train operations.