What must the system support according to the design criteria?

• A. Must support system loads and environmental changes.
• B. Must support only the color coding of components.
• C. Must support user preferences.
• D. Must support unlimited speed.

Answer: (A)

The design criteria require the system to accommodate changing loads and environmental conditions. Escalators and moving walks experience varying passenger traffic, which changes forces, moments, and dynamic loading on the structure, drive system, and safety devices. They also face environmental factors like temperature swings, humidity, dust, moisture, and vibration that can affect material properties, lubrication, clearances, and overall reliability. Designing for these variations means setting acceptable stresses, deflections, thermal expansion, and safety margins so the system remains safe and functional under all expected conditions. The other options don’t reflect engineering requirements: color coding is cosmetic labeling, user preferences aren’t a design criterion for safe operation, and unlimited speed conflicts with safety, performance limits, and control system capabilities.