Which fuse designation corresponds to the description: Low air pressure alarm stick relay?

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

Answer: (C)

In fuse designations, the label usually names the device and its function. If the description specifies a device that is a low air pressure alarm paired with a stick relay, the designation will be exactly that phrase. So the fuse label that matches the description is "Low air pressure alarm stick relay" because it directly identifies the component and its purpose. The other options point to different relays or systems (approach locking, automatic train operation, normal switch/route selection with specific initiation), which do not describe the low air pressure alarm function, so they aren’t the correct designation for this description.