What does a green flag signify to train crews?

A green flag signifies that the speed restriction has ended and that train crews can resume normal operations. This signal is a clear indication that it is safe for crews to proceed at higher speeds, as they are no longer in a restricted area. Understanding the meaning of the green flag is crucial for maintaining safe and efficient train movement, allowing crews to operate within the parameters set for their journey.

The other options reflect different signals or scenarios that do not align with the meaning of a green flag. For instance, a speed restriction would be indicated by other signals, while indications of oncoming trains or track conditions would involve different colored flags or lights to communicate such information effectively.