Which fuse designation corresponds to the description: Low air pressure alarm push button?

• 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. Low air pressure alarm stick relay.

Answer: (C)

Understanding fuse designations: the label on the fuse points to the exact device or function it protects or activates. A designation that reads “Low air pressure alarm push button” directly identifies a push button used to trigger or acknowledge an alarm when air pressure is low. That precise match makes it the correct choice, because the other options describe different components—route control elements like normal switch position route selection relays with directional initiation, or a low air pressure alarm stick relay—that are not push buttons. In other words, the designation should reflect the actual device described, and a push button for a low air pressure alarm is exactly that.