Which activity requires maintaining at least 100 feet of separation?

• A. Entering the engine cab.
• B. Walking between cars.
• C. Adjusting a knuckle.
• D. Operating the horn.

Answer: (C)

The key idea is staying out of the path of moving equipment during coupling-related tasks. When you’re adjusting a knuckle, you’re right at the connection point between cars where movement can happen suddenly as cars couple, decouple, or shift even a little. If a car lurches or the knuckle engages unexpectedly, anyone nearby could be struck or squeezed by pinch points. Keeping at least 100 feet of separation creates a safe buffer, giving you space to react and reducing the risk of contact with moving parts.

Other tasks don’t carry this same immediate risk from a coupling action, so they don’t require this particular distance. For example, entering the engine cab or operating the horn involve different safety steps and are not defined by a 100-foot separation in the same way as a knuckle adjustment. Walking between cars also exposes you to hazards like gap injuries and moving equipment, but the specified 100-foot rule is specifically tied to coupling operations where a car could move unexpectedly.