Which doors must be opened during peak hours at key stations?

During peak hours at key stations, all doors on the platform must be opened to facilitate quick and efficient boarding and alighting of passengers. This approach helps reduce congestion and allows for swift passenger flow, which is crucial during busy times when many people are entering and exiting the train. Opening all doors provides access for passengers across the entire train, ensuring that boarding can happen simultaneously at multiple points, minimizing delays and improving overall service efficiency.

In this context, options that limit access to only specific doors or sections of the train would hinder the movement of passengers, potentially leading to longer wait times and overcrowding at certain entrances. For example, only opening the front doors would funnel all passengers through a single entry point, which can create bottlenecks. Therefore, opening all doors on the platform is a clear and effective way to manage the volume of riders during busy periods.