What is the significance of "West End Ave" in train operations?

The correct choice relates to the historical and operational importance of West End Ave as a location of a train depot. This means it serves as a critical facility for the storage, maintenance, and management of trains. Depots are essential nodes in rail operations as they not only house the trains but also enable servicing and repairs, ensuring that the rolling stock is safe and ready for operation.

In contrast, the other options may describe various features associated with rail operations but do not encapsulate the primary significance of West End Ave as a facility primarily focused on the functionality and management of train operations. For example, while an identified signal is crucial in directing train movement and preventing collisions, it does not reflect the comprehensive role that a depot plays. Similarly, a street crossing pertains to where road traffic intersects with train tracks, and while a residential area may be located near train stations, it does not carry the operational implications of rail service management that a depot does.