What is necessary before a reverse movement can occur at a restricted speed?

Before a reverse movement can occur at a restricted speed, it is crucial that a crew member precedes the movement. This practice is essential for ensuring safety, as the individual in advance can alert the crew to any potential hazards or obstructions on the tracks. By having someone at the front, they can monitor the conditions and ensure that the path is clear for the reverse movement, thereby allowing for any necessary adjustments or stops to be made if they encounter an unexpected situation.

The other options, while they may involve safety protocols, do not specifically address the requirement for a crew member to ensure safe navigation during a reverse movement at a restricted speed. Having the last signal indication clear or obtaining authorization from the Dispatcher are important procedures in their own right, but they do not directly replace the need for a crew member to precede the movement, which is specifically mandated for safety during such operations.