What does the key on "W" signify?

The key on "W" signifies the east of the key switch on track G. This designation is crucial for train operations and safety, as it indicates the specific location of the key switch relative to track G. Understanding the layout and terminology is vital for train engineers, as it helps ensure proper navigation and control of the train systems throughout the network. The east side of track G might have specific operational rules or conditions that differentiate it from other areas, making this information particularly relevant for safe train maneuvers.

The other options relate to geographical or operational aspects of the railway but do not accurately describe the specific significance of the "W" key as indicated in the context of track G. Therefore, focusing on this designation is essential for maintaining clarity in train operations and adhering to protocols.