In which circumstance would you encounter a CAB Signal?

Answer: B — In an engine control compartment

The correct scenario for encountering a CAB signal is in an engine control compartment. CAB, which stands for Centralized Automatic Block signaling, is used primarily in train control systems. The signal provides the engineer with information about track conditions and system status directly in the engine compartment. This enables the conductor to receive real-time updates and ensure safe operation of the train. In contrast, a CAB signal would not typically be found on the platform during passenger boarding, since this area is more focused on passenger safety and boarding procedures rather than train control signals. Nearing a station exit does not involve communicating train operational data, as this area pertains to passenger flow and safety. Lastly, controls of an interlocking are more concerned with the management of track switches and signals between different rail lines rather than the specific CAB signaling system, which is dedicated to train operational data within the locomotive itself.