When should train brakes not be released after a stop when further movement is delayed?

The correct answer emphasizes that train brakes should not be released until operating conditions permit safe movement. This guideline is crucial for ensuring the safety of the train and its operation. When train brakes are released prematurely, it could lead to potential risks such as unintended movements or collisions if the train is not adequately controlled.

Operating conditions may include factors such as track conditions, visibility, weather, and the overall safety of the surrounding environment. By ensuring that the brakes remain engaged until it is safe to proceed, the crew can maintain control and prevent accidents. Therefore, it is the responsibility of the train crew to assess these conditions before deciding to release the brakes.

In contrast, releasing brakes only when the train arrives at the next station, at the discretion of the conductor, or when an emergency signal is given may not adequately account for the current safety conditions and could compromise safe operations. Each of these options lacks the flexibility that is often necessary to adapt to real-time conditions encountered during train operations.