Which rule indicates that signal indication will authorize a train to operate with the current of traffic?

The rule that indicates a signal indication will authorize a train to operate with the current of traffic is related to the concept of track signaling in one direction. In scenarios where tracks are signaled for operation in one direction only, the signals are specifically designed to ensure safe passage for trains moving in that prescribed direction. This establishes a clear understanding for train crews regarding their authority to proceed, as well as the requirement to adhere to signal indications that authorize such movement.

In a one-directionally signaled track environment, signal aspects provide distinct permissions to proceed, stop, or slow down based on the direction of travel, which is essential for maintaining safety and effective operations. By following the signals that indicate the current of traffic, train crews can confidently operate their trains knowing they are within safe parameters sanctioned by the signaling system. This helps prevent conflicts and collisions that could arise if trains attempted to travel against the signaling indications.

The other options involve different signaling contexts—such as two-directional signaling or various forms of authority—which do not specifically address the authorization for trains to operate with the current of traffic in a one-directional scenario. Thus, focusing on the specific lane of operation defined by one-directional signals clarifies the nature of train movement authorization under those rules.