Which statement correctly describes MU locomotives?

Which statement correctly describes MU locomotives?

• A. To control trailing units by automatic signaling
• B. To connect cable and hose connections between locomotives, allowing control of trailing units from the lead locomotive
• C. To control the headlights of all units
• D. To regulate air pressure across the consist

Answer: (B)

Multiple-unit operation is about having more than one locomotive controlled from a single lead unit. This is made possible by connecting locomotives with MU cables and air hoses. The cables carry control signals—throttle, direction, and braking commands—from the lead locomotive to the trailing units, while the hoses supply brake pipe air so braking is coordinated across all units. Because of these connections, the crew can run several locomotives as a single power unit, improving traction and efficiency on long or heavy trains. Other choices miss the main idea: automatic signaling isn’t governed by MU cables, headlights aren’t controlled through MU in the way described, and regulating air pressure across the entire consist isn’t the purpose of MU—the system distributes control signals and brake commands across the locomotives.

Multiple-unit operation is about having more than one locomotive controlled from a single lead unit. This is made possible by connecting locomotives with MU cables and air hoses. The cables carry control signals—throttle, direction, and braking commands—from the lead locomotive to the trailing units, while the hoses supply brake pipe air so braking is coordinated across all units. Because of these connections, the crew can run several locomotives as a single power unit, improving traction and efficiency on long or heavy trains.

Other choices miss the main idea: automatic signaling isn’t governed by MU cables, headlights aren’t controlled through MU in the way described, and regulating air pressure across the entire consist isn’t the purpose of MU—the system distributes control signals and brake commands across the locomotives.