When approaching an interlocking scheduled for a diverging route, what signal should be displayed?

The correct signal when approaching an interlocking scheduled for a diverging route is green or yellow over yellow. This signal indicates to the train operator that the train must prepare for a diverging aspect, meaning it will be taking a route that branches off from the main track. The presence of either a green or yellow aspect over yellow serves as a warning that the train must be prepared to reduce speed as it enters the diverging route.

In this context, the green aspect allows the operator to proceed, while the yellow indicates caution and suggests that there may be a need to slow down for the upcoming diverging path. This is crucial for operational safety, as diverging routes typically require the train to navigate curves, which necessitates a different speed profile compared to straight track approaches.

Other signals mentioned are designed for distinct conditions and rules of the railroad. For example, a red over green usually indicates that a train should stop at a signal, while blue signals are typically used in maintenance of way scenarios to indicate work zones. A white signal can denote various operational statuses or authorizations but is not relevant in the context of diverging routes at interlockings. Understanding the meaning of each signal is critical for safe and efficient train operations.