If a locomotive has flat spots on wheels longer than 2 1/2 inches, what action should be taken?

When a locomotive has flat spots on its wheels that exceed 2 1/2 inches, the appropriate response is to set it out at the first available point and limit the speed. Flat spots can indicate potential issues with the wheel's integrity and can lead to increased wear and tear on the rail infrastructure, as well as create unsafe operating conditions for the locomotive itself.

Allowing the locomotive to continue operation at regular speed could exacerbate the problem, leading to further damage and risking both safety and equipment. By setting the locomotive out, crews can prevent additional strain on the wheels and address the issue properly before resuming normal operations. Limiting speed is crucial to minimize the impact of the flat spots while ensuring the locomotive can still be moved safely to a maintenance area for inspection and repair.

The other options do not adequately address the potential risks and could lead to greater long-term issues, making the chosen action the most responsible and safety-conscious decision.