When can crew members exceed the speed shown on a permanent speed restriction sign?

Answer: C — The rear of the train has passed a permanent resume speed sign.

Crew members can exceed the speed shown on a permanent speed restriction sign specifically after the rear of the train has passed a permanent resume speed sign. This procedure is crucial because it signals that the train has safely cleared the speed restriction zone and is now allowed to operate at higher speeds again. The resume speed sign indicates that the speed limit has returned to normal or is higher than the previous restriction. This ensures that all crew members remain in compliance with safety regulations and follow established protocols for changes in speed limits. Understanding this procedure helps maintain the safety of train operations, as exceeding a speed limit before confirming clearance could lead to unsafe conditions. In contrast, the other options describe conditions that are not sufficient for safely exceeding the speed restriction. For example, simply passing a proceed indication does not necessarily mean that the speed restriction has ended, nor does just traveling a mile past the sign. Likewise, waiting for a command from the dispatcher introduces unnecessary delays and does not align with standard operating procedures that allow for automated clearance indicators like the permanent resume speed sign.