During acceleration on level or ascending grade, throttle may only be advanced to the next higher position after which action?

During acceleration on level or ascending grade, throttle may only be advanced to the next higher position after which action?

• A. After allowing the locomotive load meter to stabilize
• B. Immediately when the throttle is moved
• C. After the train reaches a designated speed
• D. After applying dynamic braking

Answer: (A)

Throttle progression during acceleration must follow the locomotive’s traction response as shown by the load meter. The load meter reflects the actual traction load (torque/current) the locomotive is delivering to the wheels. After you move the throttle to a higher position, you wait for that load reading to stabilize at a new steady value before increasing again. This ensures the brakes and adhesion remain consistent, preventing wheel slip and excessive stress on the propulsion system, especially on level or ascending grades. Pushing to the next notch immediately can cause slip or overload; waiting for a set speed isn’t the requirement here, and applying dynamic braking is a separate action that doesn’t govern when you advance the throttle.

Throttle progression during acceleration must follow the locomotive’s traction response as shown by the load meter. The load meter reflects the actual traction load (torque/current) the locomotive is delivering to the wheels. After you move the throttle to a higher position, you wait for that load reading to stabilize at a new steady value before increasing again. This ensures the brakes and adhesion remain consistent, preventing wheel slip and excessive stress on the propulsion system, especially on level or ascending grades. Pushing to the next notch immediately can cause slip or overload; waiting for a set speed isn’t the requirement here, and applying dynamic braking is a separate action that doesn’t govern when you advance the throttle.