When conducting a back up movement, what must the crew ensure regarding the train’s integrity?

In the context of a backup movement, ensuring the train's integrity is crucial for safety and operational efficiency. The correct approach requires that the train is intact and verified visually or by device. This means that all cars in the train must be connected properly and that there are no breaks in the train that could lead to derailments or accidents during the movement.

The verification process may include visual checks or the use of technical devices to confirm that all couplings are secure, and the train has not experienced any disconnections. This comprehensive verification is essential because, during a backup movement, the crew needs to be confident that every part of the train is functioning together as intended.

Other options may suggest less thorough methods of verification, focusing on parts of the train or disconnection scenarios that would not sufficiently guarantee operational safety. Ensuring that the entire train is intact minimizes risks and allows for smoother and safer operations.