What is the primary function of a Distant Signal?

The primary function of a Distant Signal is to govern the approach to an interlocking signal. Distant signals provide advance warning to train operators about the status of the upcoming interlocking signal, allowing them to adjust their speed and prepare for the action required at the interlocking, such as stopping or proceeding at a reduced speed.

This system enhances safety by ensuring that train crews have adequate information ahead of time to make informed decisions. It plays a crucial role in the overall signaling system by ensuring that trains operate smoothly and safely through complex track configurations, which may involve switches or crossings.

Other options, while relevant in the broader context of rail operations, do not capture the specific purpose of a Distant Signal. The display of a Stop indication, for instance, is typically the role of a standard signal at the interlocking itself, rather than a distant signal. Indicating train speed limits is usually managed by speedboards or other speed control systems rather than by distant signals. Informing passengers of train arrivals relates more to station signage and announcements, which are not functions of signaling equipment tailored for train operation.