Which fuse designation corresponds to the description: Normal switch position route selection relay, northward initiation, "B" end of crossover?

• A. Normal switch position route selection relay, northward initiation, "B" end of crossover.
• B. Normal switch position route selection relay, northward initiation, "A" end of crossover.
• C. Low air pressure alarm push button.
• D. Automatic train operation system.

Answer: (A)

Fuse designations identify the exact circuit by naming the device protected, the action or direction, and the physical location. The description given calls out three specifics: the device is the normal switch position route selection relay, the direction is northward initiation, and the location is the B end of the crossover. Only a designation that lists all three elements together matches this circuit precisely, so that one is the correct fuse designation. The other options point to a different end of the crossover (A end) or to unrelated equipment (low air pressure alarm push button, automatic train operation system), so they don’t fit the description.