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

• A. Normal switch position route selection relay, northward initiation, "A" end of crossover.
• B. Normal switch position route selection relay, southward initiation "A" end of crossover.
• C. Low air pressure alarm push button.
• D. Prefix for positive DC energy ( high voltage ).

Answer: (B)

Fuse designations in signaling encode what the fuse protects and how the circuit is energized. The description here specifies a normal switch position route selection relay and initiation from the south, at the A end of a crossover. The designation that names exactly that combination is the one that includes both the normal switch position route selection relay and southward initiation at the A end of the crossover, matching all the described elements.

The other options describe different things: one uses the opposite (northward initiation), another points to a distinct device altogether (low air pressure alarm push button), and the last describes a general prefix for positive DC energy rather than a turnout-related fuse.