When the conductor announces "going between," what must the engineer do in response?

When the conductor announces "going between," it indicates that work is being done in a position where personnel will be placing themselves between cars. Therefore, the proper response for the engineer is to fully apply the independent brake and center the reverser. This action is critical for ensuring safety, as it prevents unintended movement of the train while the crew is working between the cars.

The application of the independent brake stabilizes the train and secures it in place, while centering the reverser prevents any possibility of the train moving in either direction. This is a safety measure to safeguard the crew and allows them to perform their duties without the risk of being struck or caught by unintended train movement.

Other responses would not adequately ensure the safety of all personnel who may be working in that area since they may either create movement or fail to respond adequately to the hazard posed by working between the cars.