What must an assistant conductor do when their assignment is adjusted to work between 12:01am and 3:59am?

When an assistant conductor's assignment is adjusted to work during the hours of 12:01am and 3:59am, it is essential that they stop performing covered service no later than 11:55pm. This is crucial because it ensures that there is a clear transition period before the new assignment takes effect. By stopping covered service at this designated time, the assistant conductor is aligning with operational protocols that aim to maintain safety, schedule adherence, and appropriate handover of responsibilities.

The timing is significant in the context of rail operations, as it allows for proper coordination and transition between crews. If the assistant conductor were to continue service past this cut-off time, it could lead to potential confusion, safety issues, or disruptions in the service schedule. Thus, stopping covered service at 11:55pm is a necessary procedural step to facilitate an orderly shift to the new assignment.