At what point is a train allowed to resume maximum speed after passing a stop indication in CTC?

The correct choice indicates that a train is allowed to resume maximum speed after it has traveled two miles or when the leading wheels pass the opposing distant signal after passing a stop indication in a Centralized Traffic Control (CTC) system. This rule ensures that the train has had sufficient distance to verify that the track is clear ahead and that signals are indicating a safe operating condition.

When the leading wheels pass the opposing distant signal, it signifies that the train has moved far enough beyond the stop signal that it can be confident no conflicting movements are present. The two-mile distance is mainly a safety buffer that provides time for the crew to verify signals and track conditions. This approach emphasizes safety and is in line with operational protocols that prioritize the well-being of passengers and the integrity of the rail network.

In contrast, options suggesting that the train may resume speed based on confirmations from the next signal or checks of routes do not provide the specific conditions necessary to ensure safety in the context of CTC systems. This reinforces the importance of a clear understanding of signals and track conditions before resuming high speeds.