What should be done immediately after shearing if the rail temperature is 60°F and there's light rain?

Applying a weld cooling cover immediately after shearing is essential when working with thermite welding, particularly under the circumstances described—specifically, a rail temperature of 60°F and light rain. The purpose of a weld cooling cover is to assist in controlling the temperature of the weld and promote proper solidification. This is particularly important because the light rain could potentially introduce moisture and cooling variations that might affect the weld quality.

When the rail temperature is around 60°F, it is close to the lower acceptable limit for optimal welding conditions. Moisture from the rain could also interact with hot metal, leading to issues such as steam generation, which can compromise the integrity of the weld. The cooling cover helps maintain consistent conditions around the weld area, preventing rapid cooling or thermal shock that could lead to defects.

Options suggesting stopping all welding operations or rechecking the rail temperature may not actively address immediate concerns regarding the weld area, and waiting for the rain to stop could delay necessary processes without enhancing the quality of the weld. Thus, applying a weld cooling cover is the most proactive and effective choice to ensure the integrity and durability of the weld in these environmental conditions.