What should the T/O verify before coupling into another car?

Verifying that the coupler is aligned is essential before coupling into another car because proper alignment ensures a safe and efficient connection between the cars. When the coupler is aligned correctly, it allows for a smooth engagement, reducing the risk of damage to the coupler mechanism or the cars themselves. Proper alignment also helps to ensure that the train can operate effectively once coupled, as misalignment could lead to issues during operation.

In contrast, while applying the brakes and ensuring the lights are functioning are critical safety checks, they do not directly pertain to the mechanical process of coupling the cars. Additionally, both cars being in motion would be contrary to the procedure because coupling requires both cars to be stationary to ensure safety and accuracy in the connection process. Therefore, ensuring the coupler is properly aligned is the most critical step to facilitate a safe and effective coupling.