What is indicated by the 'Doors to Open' signal during station stops?

The 'Doors to Open' signal during station stops indicates which doors are enabled to open. This signal is crucial for both train operators and passengers, as it directly informs them where they can safely disembark or board the train. When the signal is activated, it ensures that only the designated doors will open, promoting safety and efficiency during the boarding process. This signal allows train crew members to manage the flow of passengers effectively, ensuring a smooth and orderly station stop.

While other options may describe various operational conditions or safety protocols, they do not accurately reflect the specific function of the 'Doors to Open' signal. For instance, indicating that the train is out of service or that it will continue without stopping pertains to different operational statuses. Emergency procedures would relate to safety responses to incidents rather than standard boarding operations. Understanding the specific function of the 'Doors to Open' signal is critical for the safe and efficient management of passenger flow at stations.